# usefulweb.app

> A network of 234 focused, deterministic tools. Every tool has a human page, a JSON API, an OpenAPI description and an MCP tool that all return the same result (inputs, result, units, assumptions, sources, timestamps).

## Machine interfaces
- Tool catalog (JSON): https://usefulweb.app/api/v1/tools
- OpenAPI (all tools): https://usefulweb.app/openapi.json
- MCP server (all tools + workflows): https://usefulweb.app/mcp
- Pick a tool for a natural-language request: POST https://usefulweb.app/api/v1/tools/prompt-to-tool-router/calculate {"request": "..."}

## Tools
- [HeaderLens](https://headerlens.usefulweb.app/): Is a website down? Multi-region status, redirects, TLS and security headers. API: POST https://usefulweb.app/api/v1/tools/headerlens/calculate
- [Cancellation Navigator](https://cancellationnavigator.usefulweb.app/): Verified steps to cancel Netflix, Spotify, Prime & more, plus a cancellation letter. API: POST https://usefulweb.app/api/v1/tools/cancellation-navigator/calculate
- [Deadline Decoder](https://deadlinedecoder.usefulweb.app/): Find every deadline, required action and consequence in a letter or notice. API: POST https://usefulweb.app/api/v1/tools/deadline-decoder/calculate
- [Decision Simulator](https://decisionsimulator.usefulweb.app/): Compare 2–6 choices by expected value, worst case, best case and minimax regret. API: POST https://usefulweb.app/api/v1/tools/decision-simulator/calculate
- [Form Translator](https://formtranslator.usefulweb.app/): Plain-language help for confusing forms: field-by-field hints and jargon explained. API: POST https://usefulweb.app/api/v1/tools/form-translator/calculate
- [How Long Will It Last?](https://howlongwillitlast.usefulweb.app/): Estimate remaining life of appliances and home components and plan the replacement. API: POST https://usefulweb.app/api/v1/tools/how-long-will-it-last/calculate
- [Is It Worth It?](https://isitworthit.usefulweb.app/): Buy, rent, repair or subscribe? Compare total cost and NPV over the years you need it. API: POST https://usefulweb.app/api/v1/tools/is-it-worth-it/calculate
- [Life Admin Generator](https://lifeadmingenerator.usefulweb.app/): A dated to-do list for moving, marriage, a baby, a new job and other life events. API: POST https://usefulweb.app/api/v1/tools/life-admin-generator/calculate
- [Repair or Replace](https://repairorreplace.usefulweb.app/): Fix it or buy new? The 50% rule plus a cost-per-year check, with a clear verdict. API: POST https://usefulweb.app/api/v1/tools/repair-or-replace/calculate
- [True Cost Calculator](https://truecostcalculator.usefulweb.app/): What a car, pet, appliance, home or gadget really costs per year, month and day. API: POST https://usefulweb.app/api/v1/tools/true-cost-calculator/calculate
- [Bill Detective](https://billdetective.usefulweb.app/): Spot spikes, price changes and calculation errors across your utility bills. API: POST https://usefulweb.app/api/v1/tools/bill-detective/calculate
- [Break-even Explorer](https://breakevenexplorer.usefulweb.app/): When does an investment pay for itself? Payback, NPV and IRR for solar, EVs, heat pumps… API: POST https://usefulweb.app/api/v1/tools/break-even-explorer/calculate
- [Bulk Buy Brain](https://bulkbuybrain.usefulweb.app/): Is the bulk pack really cheaper once waste, storage and tied-up cash are counted? API: POST https://usefulweb.app/api/v1/tools/bulk-buy-brain/calculate
- [Currency Converter](https://currencyconverter.usefulweb.app/): Convert an amount into several currencies at ECB euro reference rates, with rate date and source. API: POST https://usefulweb.app/api/v1/tools/currency-converter/calculate
- [Hidden Fee Finder](https://hiddenfeefinder.usefulweb.app/): Paste a quote, contract or invoice and see every fee, tax, penalty and add-on. API: POST https://usefulweb.app/api/v1/tools/hidden-fee-finder/calculate
- [Historical FX Chart](https://historicalfxchart.usefulweb.app/): Chart exchange rates over time from ECB data: min, max, average, change, volatility and CSV export. API: POST https://usefulweb.app/api/v1/tools/historical-fx-chart/calculate
- [Inflation Time Machine](https://inflationtimemachine.usefulweb.app/): What was money from one year worth in another? CPI-based, 20 countries, World Bank data. API: POST https://usefulweb.app/api/v1/tools/inflation-time-machine/calculate
- [Multi-Currency Invoice Calculator](https://multicurrencyinvoicecalculator.usefulweb.app/): Convert invoice lines in different currencies at ECB reference rates, with VAT, rounding and totals. API: POST https://usefulweb.app/api/v1/tools/multi-currency-invoice-calculator/calculate
- [Price Per Everything](https://pricepereverything.usefulweb.app/): Compare products by price per gram, use, serving, hour or year of life. API: POST https://usefulweb.app/api/v1/tools/price-per-everything/calculate
- [Salary Reality Check](https://salaryrealitycheck.usefulweb.app/): Compare job offers by real net pay per hour, including commute time and living costs. API: POST https://usefulweb.app/api/v1/tools/salary-reality-check/calculate
- [Subscription Stack](https://subscriptionstack.usefulweb.app/): Add up every subscription, spot overlaps and see which ones to cancel and what you save. API: POST https://usefulweb.app/api/v1/tools/subscription-stack/calculate
- [Travel Exchange Fee Calculator](https://travelexchangefeecalculator.usefulweb.app/): Compare what cards, ATMs, DCC and exchange bureaus really cost abroad vs the ECB reference rate. API: POST https://usefulweb.app/api/v1/tools/travel-exchange-fee-calculator/calculate
- [Warranty Value Calculator](https://warrantyvaluecalculator.usefulweb.app/): Is the extended warranty worth it? Expected payout vs. price and break-even failure rate. API: POST https://usefulweb.app/api/v1/tools/warranty-value-calculator/calculate
- [Food Storage Guide](https://foodstorageguide.usefulweb.app/): How long is food safe in the fridge or freezer? Dates from the official FoodSafety.gov chart. API: POST https://usefulweb.app/api/v1/tools/food-storage-guide/calculate
- [Household Chore Rotator](https://householdchorerotator.usefulweb.app/): Fair chore rotation by effort and availability, with per-person totals and a calendar. API: POST https://usefulweb.app/api/v1/tools/household-chore-rotator/calculate
- [Household Maintenance Calendar](https://householdmaintenancecalendar.usefulweb.app/): A dated home maintenance schedule for your appliances and features, as a calendar file. API: POST https://usefulweb.app/api/v1/tools/household-maintenance-calendar/calculate
- [Jet Lag Planner](https://jetlagplanner.usefulweb.app/): A day-by-day sleep, light and caffeine plan to beat jet lag, with calendar export. API: POST https://usefulweb.app/api/v1/tools/jet-lag-planner/calculate
- [Leftover Chef](https://leftoverchef.usefulweb.app/): Turn leftovers and fridge odds and ends into 5 recipe ideas, using what expires first. API: POST https://usefulweb.app/api/v1/tools/leftover-chef/calculate
- [Moving Box Planner](https://movingboxplanner.usefulweb.app/): How many moving boxes, how much tape, which truck and when to start packing. API: POST https://usefulweb.app/api/v1/tools/moving-box-planner/calculate
- [Room Layout Optimizer](https://roomlayoutoptimizer.usefulweb.app/): Auto-arrange furniture in a room around doors, windows and a clear walkway. API: POST https://usefulweb.app/api/v1/tools/room-layout-optimizer/calculate
- [Travel Connection Checker](https://travelconnectionchecker.usefulweb.app/): Estimate your odds of making a flight connection, step by step. API: POST https://usefulweb.app/api/v1/tools/travel-connection-checker/calculate
- [Weekly Meal Planner](https://weeklymealplanner.usefulweb.app/): Turn your pantry and its expiry dates into a 7-day dinner plan and a shopping list. API: POST https://usefulweb.app/api/v1/tools/weekly-meal-planner/calculate
- [Will It Fit?](https://willitfit.usefulweb.app/): Check if a sofa, wardrobe or box fits through doors, corners, stairs and lifts. API: POST https://usefulweb.app/api/v1/tools/will-it-fit/calculate
- [AI Answer Verifier](https://aianswerverifier.usefulweb.app/): Split an AI answer into claims and see which ones your sources actually support. API: POST https://usefulweb.app/api/v1/tools/ai-answer-verifier/calculate
- [Error Message Translator](https://errormessagetranslator.usefulweb.app/): Paste a technical error and get the plain-English cause and troubleshooting steps. API: POST https://usefulweb.app/api/v1/tools/error-message-translator/calculate
- [File Format Doctor](https://fileformatdoctor.usefulweb.app/): Find out what a file really is from its bytes, why it will not open and how to convert it. API: POST https://usefulweb.app/api/v1/tools/file-format-doctor/calculate
- [Privacy Policy Decoder](https://privacypolicydecoder.usefulweb.app/): What a privacy policy says it collects, shares, sells and keeps — with quoted evidence. API: POST https://usefulweb.app/api/v1/tools/privacy-policy-decoder/calculate
- [Prompt-to-Tool Router](https://prompttotoolrouter.usefulweb.app/): Describe your problem in plain words and get the right tools and order to use them. API: POST https://usefulweb.app/api/v1/tools/prompt-to-tool-router/calculate
- [Scam Signal Checker](https://scamsignalchecker.usefulweb.app/): Check a message or link for common scam and phishing warning signs — without clicking. API: POST https://usefulweb.app/api/v1/tools/scam-signal-checker/calculate
- [Screenshot to Steps](https://screenshottosteps.usefulweb.app/): Turn a screenshot of an app or website into numbered steps for what you want to do. API: POST https://usefulweb.app/api/v1/tools/screenshot-to-steps/calculate
- [Website Change Explainer](https://websitechangeexplainer.usefulweb.app/): Compare two versions of a page and see which changes matter: prices, terms, dates, links. API: POST https://usefulweb.app/api/v1/tools/website-change-explainer/calculate
- [Accessibility Fixer](https://accessibilityfixer.usefulweb.app/): Turn WCAG 2.2 problems in your HTML into concrete code fixes, grouped by effort. API: POST https://usefulweb.app/api/v1/tools/accessibility-fixer/calculate
- [Before You Sign](https://beforeyousign.usefulweb.app/): Spot risky contract clauses (renewal, notice, liability, non-compete…) before you sign. API: POST https://usefulweb.app/api/v1/tools/before-you-sign/calculate
- [Digital Estate Organizer](https://digitalestateorganizer.usefulweb.app/): List your online accounts and get a prioritised plan for what happens to them – no passwords needed. API: POST https://usefulweb.app/api/v1/tools/digital-estate-organizer/calculate
- [Disaster Prep Builder](https://disasterprepbuilder.usefulweb.app/): Build an emergency supply list for your household from official Ready.gov or BBK guidance. API: POST https://usefulweb.app/api/v1/tools/disaster-prep-builder/calculate
- [The Compatibility Engine](https://compatibilityengine.usefulweb.app/): Will this charger, cable, version or PC part work together? Rule-based checks with margins. API: POST https://usefulweb.app/api/v1/tools/compatibility-engine/calculate
- [What Changed in This Law?](https://whatchangedinthislaw.usefulweb.app/): Compare two versions of a law or regulation section by section, with changed numbers and deadlines. API: POST https://usefulweb.app/api/v1/tools/what-changed-in-this-law/calculate
- [Accessibility Snapshot](https://a11ysnapshot.usefulweb.app/): Static WCAG 2.2 snapshot of a page: findings by severity, evidence and manual checks. API: POST https://usefulweb.app/api/v1/tools/a11y-snapshot/calculate
- [Browser Compatibility Checker](https://browsercompatibilitychecker.usefulweb.app/): Which browsers support a CSS property, JS API or HTML element? MDN data + Baseline status. API: POST https://usefulweb.app/api/v1/tools/browser-compatibility-checker/calculate
- [CiteShape](https://citeshape.usefulweb.app/): Paste a DOI, ORCID iD, ISBN or arXiv ID: validated, resolved, and formatted as APA, BibTeX and RIS. API: POST https://usefulweb.app/api/v1/tools/citeshape/calculate
- [CyberChef-lite Pipeline](https://cybercheflitepipeline.usefulweb.app/): One-click decoding recipes: JWT, base64 → gunzip → JSON, double URL decode, hex dump. API: POST https://usefulweb.app/api/v1/tools/cyberchef-lite-pipeline/calculate
- [DataFresh](https://datafresh.usefulweb.app/): Is this dataset or API still fresh? Newest record, update cadence check and schema drift. API: POST https://usefulweb.app/api/v1/tools/datafresh/calculate
- [FileFit](https://filefit.usefulweb.app/): Can this app open, edit or convert that file format? Verified facts with sources. API: POST https://usefulweb.app/api/v1/tools/filefit/calculate
- [LocaleKit Country Format Rules](https://localekit.usefulweb.app/): Address form fields, postal-code regex, calling code and date formats for any country. API: POST https://usefulweb.app/api/v1/tools/localekit/calculate
- [Network Speed Tester](https://networkspeedtester.usefulweb.app/): Measure latency, jitter, download and upload speed between your browser and our server. API: POST https://usefulweb.app/api/v1/tools/network-speed-tester/calculate
- [RuleDate Deadline Calculator](https://ruledate.usefulweb.app/): Business-day and deadline maths with public holidays and a step-by-step rule trace. API: POST https://usefulweb.app/api/v1/tools/ruledate/calculate
- [Safe Markdown Preview](https://safemarkdownpreview.usefulweb.app/): Render Markdown with GFM tables and footnotes to sanitised HTML and see what was removed. API: POST https://usefulweb.app/api/v1/tools/safe-markdown-preview/calculate
- [TimeFair Meeting Planner](https://timefair.usefulweb.app/): Find fair meeting times across time zones, with DST-exact local times and rotation. API: POST https://usefulweb.app/api/v1/tools/timefair/calculate
- [Unicode Inspector](https://unicodeinspector.usefulweb.app/): Every code point with name, script and bytes, plus hidden characters and look-alikes. API: POST https://usefulweb.app/api/v1/tools/unicode-inspector/calculate
- [UnitProof Unit Calculator](https://unitproof.usefulweb.app/): Unit maths you can audit: dimension check, exact factors and a full derivation tree. API: POST https://usefulweb.app/api/v1/tools/unitproof/calculate
- [Unix Permission Calculator](https://unixpermissioncalculator.usefulweb.app/): chmod calculator: octal ↔ rwx, setuid/sticky, u+x style changes, umask and ls -l. API: POST https://usefulweb.app/api/v1/tools/unix-permission-calculator/calculate
- [Account Abstraction Explorer](https://accountabstractionexplorer.usefulweb.app/): Decode ERC-4337 bundles: UserOperations, paymasters, gas per op, deployed smart accounts. API: POST https://usefulweb.app/api/v1/tools/account-abstraction-explorer/calculate
- [Blockchain Incident Replay](https://blockchainincidentreplay.usefulweb.app/): Replay an exploit from tx hashes: ordered timeline, fund-flow graph and who profited. API: POST https://usefulweb.app/api/v1/tools/blockchain-incident-replay/calculate
- [Bridge Transfer Tracker](https://bridgetransfertracker.usefulweb.app/): Where is my bridged money? Finds the bridge deposit in a transaction and checks if it arrived. API: POST https://usefulweb.app/api/v1/tools/bridge-transfer-tracker/calculate
- [Cross-Chain Transaction Explorer](https://crosschaintransactionexplorer.usefulweb.app/): Follow one transaction across chains: source tx, bridge deposit and destination fill on a timeline. API: POST https://usefulweb.app/api/v1/tools/cross-chain-transaction-explorer/calculate
- [DAO Governance Explorer](https://daogovernanceexplorer.usefulweb.app/): Snapshot proposals, vote concentration, Governor state and treasury balances in one view. API: POST https://usefulweb.app/api/v1/tools/dao-governance-explorer/calculate
- [DeFi Liquidation Explorer](https://defiliquidationexplorer.usefulweb.app/): Recent Aave V3 liquidations in USD, who liquidated whom, and a live health-factor check. API: POST https://usefulweb.app/api/v1/tools/defi-liquidation-explorer/calculate
- [Gas Fee Intelligence Explorer](https://gasfeeintelligenceexplorer.usefulweb.app/): Live gas on 7 EVM chains: base fee, tips, trend and the USD cost of transfers and swaps. API: POST https://usefulweb.app/api/v1/tools/gas-fee-intelligence-explorer/calculate
- [MEV Explorer](https://mevexplorer.usefulweb.app/): Who extracted value in this block? Sandwiches, arbitrage, liquidations, builder and tips. API: POST https://usefulweb.app/api/v1/tools/mev-explorer/calculate
- [Rollup Batch Explorer](https://rollupbatchexplorer.usefulweb.app/): How L2 transactions reach Ethereum: unsafe → safe → finalized, blobs, batch costs, withdrawal waits. API: POST https://usefulweb.app/api/v1/tools/rollup-batch-explorer/calculate
- [Smart Contract Relationship Graph](https://smartcontractrelationshipgraph.usefulweb.app/): Map a contract's proxy, implementation, admin, owner, deployer/factory and token links as a graph. API: POST https://usefulweb.app/api/v1/tools/smart-contract-relationship-graph/calculate
- [Smart Contract Upgrade Explorer](https://contractupgradeexplorer.usefulweb.app/): Is this smart contract upgradeable, who controls upgrades, and what changed? API: POST https://usefulweb.app/api/v1/tools/contract-upgrade-explorer/calculate
- [Stablecoin Flow Explorer](https://stablecoinflowexplorer.usefulweb.app/): USDC/USDT supply per chain, recent mints, burns and whale transfers, cross-chain totals. API: POST https://usefulweb.app/api/v1/tools/stablecoin-flow-explorer/calculate
- [Token Unlock Explorer](https://tokenunlockexplorer.usefulweb.app/): Model token vesting (cliff, linear, monthly, tranches, TGE) or audit a VestingWallet. API: POST https://usefulweb.app/api/v1/tools/token-unlock-explorer/calculate
- [Transaction Decoder](https://transactiondecoder.usefulweb.app/): See what an EVM transaction actually did: call, events, token transfers, fee, finality. API: POST https://usefulweb.app/api/v1/tools/transaction-decoder/calculate
- [Wallet Permission Explorer](https://walletpermissionexplorer.usefulweb.app/): Who can move your tokens? Allowances, Permit2, NFT operators and EIP-7702 delegation, with risk. API: POST https://usefulweb.app/api/v1/tools/wallet-permission-explorer/calculate
- [ASN Relationship Explorer](https://asnrelationshipexplorer.usefulweb.app/): An autonomous system at a glance: holder, country, BGP neighbours and announced prefixes. API: POST https://usefulweb.app/api/v1/tools/asn-relationship-explorer/calculate
- [BGP Route Explorer](https://bgprouteexplorer.usefulweb.app/): Who announces an IP or prefix in BGP: origin ASes, RPKI validity, visibility and origin changes. API: POST https://usefulweb.app/api/v1/tools/bgp-route-explorer/calculate
- [CDN Behaviour Explorer](https://cdnbehaviorexplorer.usefulweb.app/): Which CDN serves a URL, whether it caches it (HIT/MISS, Age, TTL) and how, from two requests. API: POST https://usefulweb.app/api/v1/tools/cdn-behavior-explorer/calculate
- [Certificate Transparency Explorer](https://certificatetransparencyexplorer.usefulweb.app/): Every logged certificate for a domain: history, issuers, subdomains, wildcards and expiry. API: POST https://usefulweb.app/api/v1/tools/certificate-transparency-explorer/calculate
- [DNS + Certificate Explorer](https://dnscertificateexplorer.usefulweb.app/): DNS records, e-mail security, CAA, live TLS certificate and CT history for a domain. API: POST https://usefulweb.app/api/v1/tools/dns-certificate-explorer/calculate
- [Domain History Graph](https://domainhistorygraph.usefulweb.app/): Registration, DNS, hosting networks, certificates and Wayback captures of a domain as a timeline. API: POST https://usefulweb.app/api/v1/tools/domain-history-graph/calculate
- [E-mail Infrastructure Explorer](https://emailinfrastructureexplorer.usefulweb.app/): MX, SPF lookups, DMARC, DKIM, MTA-STS, TLS-RPT and BIMI for a domain, scored with fixes. API: POST https://usefulweb.app/api/v1/tools/email-infrastructure-explorer/calculate
- [Global DNS Explorer](https://globaldnsexplorer.usefulweb.app/): Ask every authoritative name server and public resolvers: records, propagation, DNSSEC, mistakes. API: POST https://usefulweb.app/api/v1/tools/global-dns-explorer/calculate
- [HTTP Technology Explorer](https://httptechnologyexplorer.usefulweb.app/): Headers, compression, caching, HTTP/2-3 hints, redirects, security and tech stack for a URL. API: POST https://usefulweb.app/api/v1/tools/http-technology-explorer/calculate
- [Internet Outage Atlas](https://internetoutageatlas.usefulweb.app/): Correlate public outage signals (IODA, RIPEstat BGP, live probe) for a country, ASN or domain. API: POST https://usefulweb.app/api/v1/tools/internet-outage-atlas/calculate
- [IPv6 Readiness Explorer](https://ipv6readinessexplorer.usefulweb.app/): Is a domain reachable over IPv6? Web, DNS and mail checks, address classes and a scored report. API: POST https://usefulweb.app/api/v1/tools/ipv6-readiness-explorer/calculate
- [Artifact Provenance Explorer](https://artifactprovenanceexplorer.usefulweb.app/): Verify npm build provenance: Sigstore signature, transparency log, source repo and commit. API: POST https://usefulweb.app/api/v1/tools/artifact-provenance-explorer/calculate
- [C2PA Credentials Inspector](https://c2pacredentialsinspector.usefulweb.app/): Read C2PA Content Credentials in images and videos: actions, AI hints, signer and signature. API: POST https://usefulweb.app/api/v1/tools/c2pa-credentials-inspector/calculate
- [Container Image Explorer](https://containerimageexplorer.usefulweb.app/): Inspect a container image: platforms, layers, base image, root user, labels and cosign signature. API: POST https://usefulweb.app/api/v1/tools/container-image-explorer/calculate
- [CVE Relationship Graph](https://cverelationshipgraph.usefulweb.app/): One CVE or GHSA as a graph: aliases, affected packages, fixed versions, KEV status and EPSS. API: POST https://usefulweb.app/api/v1/tools/cve-relationship-graph/calculate
- [Dependency Vulnerability Explorer](https://dependencyvulnerabilityexplorer.usefulweb.app/): Known vulnerabilities in your dependencies, and the version that fixes each one. API: POST https://usefulweb.app/api/v1/tools/dependency-vulnerability-explorer/calculate
- [OAuth Permission Explorer](https://oauthpermissionexplorer.usefulweb.app/): What an OAuth consent request really allows: scopes, risky combinations and flow problems. API: POST https://usefulweb.app/api/v1/tools/oauth-permission-explorer/calculate
- [Open Source Trust Explorer](https://opensourcetrustexplorer.usefulweb.app/): Is this open-source project maintained and trustworthy? Scorecard, activity and provenance. API: POST https://usefulweb.app/api/v1/tools/open-source-trust-explorer/calculate
- [Package Ecosystem Graph](https://packageecosystemgraph.usefulweb.app/): Who depends on what: resolved dependency graph, duplicates and the blast radius of breaking changes. API: POST https://usefulweb.app/api/v1/tools/package-ecosystem-graph/calculate
- [Passkey & WebAuthn Tester](https://passkeywebauthntester.usefulweb.app/): Test passkeys in your browser and decode WebAuthn responses: flags, AAGUID, signatures. API: POST https://usefulweb.app/api/v1/tools/passkey-webauthn-tester/calculate
- [SBOM Explorer](https://sbomexplorer.usefulweb.app/): Open a CycloneDX or SPDX SBOM: components, licences, dependency tree and known vulnerabilities. API: POST https://usefulweb.app/api/v1/tools/sbom-explorer/calculate
- [SBOM License Checker](https://sbomlicensechecker.usefulweb.app/): Check SBOM licences: SPDX expressions, copyleft class and conflicts with your project licence. API: POST https://usefulweb.app/api/v1/tools/sbom-license-checker/calculate
- [Security Advisory Timeline](https://securityadvisorytimeline.usefulweb.app/): Disclosures, affected ranges, fixes and withdrawals for a package on one timeline, with time-to-fix. API: POST https://usefulweb.app/api/v1/tools/security-advisory-timeline/calculate
- [Security Configuration Scanner](https://securityconfigurationscanner.usefulweb.app/): Passive, graded check of a domain's TLS, security headers, DNS security and security.txt. API: POST https://usefulweb.app/api/v1/tools/security-configuration-scanner/calculate
- [API Explorer of Explorers](https://apiexplorerofexplorers.usefulweb.app/): Search 2,500+ public APIs or summarise any OpenAPI spec: servers, auth, endpoints, changes. API: POST https://usefulweb.app/api/v1/tools/api-explorer-of-explorers/calculate
- [CI/CD Failure Explorer](https://cicdfailureexplorer.usefulweb.app/): Paste CI logs from several runs: root cause per run, grouped signatures, top causes and fixes. API: POST https://usefulweb.app/api/v1/tools/cicd-failure-explorer/calculate
- [Cron Job Explorer](https://cronjobexplorer.usefulweb.app/): Paste a crontab or CronJob YAML: plain-English schedules, DST-exact next runs, herds and overlaps. API: POST https://usefulweb.app/api/v1/tools/cron-job-explorer/calculate
- [Data Lineage Explorer](https://datalineageexplorer.usefulweb.app/): Paste SQL or dbt models: table lineage graph, column lineage and upstream/downstream of any field. API: POST https://usefulweb.app/api/v1/tools/data-lineage-explorer/calculate
- [Distributed Trace Explorer](https://distributedtraceexplorer.usefulweb.app/): Paste an OTLP, Jaeger or Zipkin trace: span tree, critical path, self-time, N+1 calls and errors. API: POST https://usefulweb.app/api/v1/tools/distributed-trace-explorer/calculate
- [Kubernetes Event Explorer](https://kuberneteseventexplorer.usefulweb.app/): Paste kubectl events and get a timeline, reason taxonomy and likely root causes per workload. API: POST https://usefulweb.app/api/v1/tools/kubernetes-event-explorer/calculate
- [OpenAPI Diff Explorer](https://openapidiffexplorer.usefulweb.app/): Compare two versions of an OpenAPI spec and see exactly which changes break clients. API: POST https://usefulweb.app/api/v1/tools/openapi-diff-explorer/calculate
- [Query Plan Visualizer](https://queryplanvisualizer.usefulweb.app/): PostgreSQL EXPLAIN (ANALYZE) or MySQL EXPLAIN JSON → plan tree, hot nodes and index suggestions. API: POST https://usefulweb.app/api/v1/tools/query-plan-visualizer/calculate
- [Serverless Performance Explorer](https://serverlessperformanceexplorer.usefulweb.app/): Lambda REPORT lines → cold-start rate, p50/p95/p99, memory right-sizing and cost per 1M calls. API: POST https://usefulweb.app/api/v1/tools/serverless-performance-explorer/calculate
- [Terraform Plan & Drift Explorer](https://terraformdriftexplorer.usefulweb.app/): Paste terraform show -json: drift, replacement reasons, attribute diffs and risky deletes. API: POST https://usefulweb.app/api/v1/tools/terraform-drift-explorer/calculate
- [Agent Permission Graph](https://agentpermissiongraph.usefulweb.app/): See what your AI agent can reach: MCP servers, commands, files, network and secrets – with risks. API: POST https://usefulweb.app/api/v1/tools/agent-permission-graph/calculate
- [AI Agent Tool Explorer](https://aiagenttoolexplorer.usefulweb.app/): Index of tools AI agents can call: this site, the MCP Registry or your definitions, by capability. API: POST https://usefulweb.app/api/v1/tools/ai-agent-tool-explorer/calculate
- [AI Model Compatibility Explorer](https://aimodelcompatibilityexplorer.usefulweb.app/): Which LLMs take images, audio or files, fit your context and support tools or structured outputs? API: POST https://usefulweb.app/api/v1/tools/ai-model-compatibility-explorer/calculate
- [AI Tool-Call Trace Explorer](https://toolcalltraceexplorer.usefulweb.app/): Paste an agent transcript: see every tool call in order, with errors, timings, retries and loops. API: POST https://usefulweb.app/api/v1/tools/tool-call-trace-explorer/calculate
- [AI Website Readiness Explorer](https://aiwebsitereadinessexplorer.usefulweb.app/): Can ChatGPT, Claude, Perplexity and AI agents read your website? Explainable score. API: POST https://usefulweb.app/api/v1/tools/ai-website-readiness-explorer/calculate
- [LLM Cost Explorer](https://llmcostexplorer.usefulweb.app/): Monthly LLM API cost per model for your workload, with prompt-caching and batch savings. API: POST https://usefulweb.app/api/v1/tools/llm-cost-explorer/calculate
- [MCP Server Explorer](https://mcpserverexplorer.usefulweb.app/): Inspect any MCP server before you connect an AI agent: tools, permissions, risks, changes over time. API: POST https://usefulweb.app/api/v1/tools/mcp-server-explorer/calculate
- [Model Behavior Regression Explorer](https://modelbehaviorregressionexplorer.usefulweb.app/): Compare eval results of two model versions: accuracy, regressions, McNemar p-value, flaky items. API: POST https://usefulweb.app/api/v1/tools/model-behavior-regression-explorer/calculate
- [RAG Citation Debugger](https://ragcitationdebugger.usefulweb.app/): Check a RAG answer's citations against the retrieved chunks: uncited claims, wrong sources, numbers. API: POST https://usefulweb.app/api/v1/tools/rag-citation-debugger/calculate
- [Structured Output Validator](https://structuredoutputvalidator.usefulweb.app/): Validate AI JSON output against a JSON Schema: parse errors with line/column, plain-language fixes. API: POST https://usefulweb.app/api/v1/tools/structured-output-validator/calculate
- [Energy Grid Explorer](https://energygridexplorer.usefulweb.app/): Generation mix, load, renewable share, cross-border flows and power prices for European grids. API: POST https://usefulweb.app/api/v1/tools/energy-grid-explorer/calculate
- [Internet Archive Change Explorer](https://internetarchivechangeexplorer.usefulweb.app/): See how a web page changed in the Wayback Machine: capture timeline plus the changes that matter. API: POST https://usefulweb.app/api/v1/tools/internet-archive-change-explorer/calculate
- [Public Spending Explorer](https://publicspendingexplorer.usefulweb.app/): Search government contracts and grants: who pays whom, totals per agency and vendor. API: POST https://usefulweb.app/api/v1/tools/public-spending-explorer/calculate
- [Satellite Change Explorer](https://satellitechangeexplorer.usefulweb.app/): Compare NASA satellite images of any place on two dates: true colour, NDVI, night lights. API: POST https://usefulweb.app/api/v1/tools/satellite-change-explorer/calculate
- [Software Adoption Explorer](https://softwareadoptionexplorer.usefulweb.app/): Open-source usage signals: weekly downloads, growth and version adoption for npm, PyPI, crates. API: POST https://usefulweb.app/api/v1/tools/software-adoption-explorer/calculate
- [Explorer of Everything](https://explore.usefulweb.app/): Search transactions, contracts, domains, packages, advisories, MCP servers and websites in one box. API: POST https://usefulweb.app/api/v1/tools/explore/calculate
- [Chore Roulette](https://choreroulette.usefulweb.app/): Spin a fair chore rota: random but balanced by effort, with a “not again” rule. API: POST https://usefulweb.app/api/v1/tools/chore-roulette/calculate
- [Elo/Glicko Rating Lab](https://eloglickoratinglab.usefulweb.app/): Rate players from game results with Elo, Glicko-1 and Glicko-2; history chart and win odds. API: POST https://usefulweb.app/api/v1/tools/elo-glicko-rating-lab/calculate
- [Emoji Cipher Playground](https://emojicipherplayground.usefulweb.app/): Turn secret notes into emoji and back: substitution, Caesar shift and base-emoji. API: POST https://usefulweb.app/api/v1/tools/emoji-cipher-playground/calculate
- [Equation Art Studio](https://equationartstudio.usefulweb.app/): Turn math into art: parametric, polar, Lissajous, rose and spirograph curves. API: POST https://usefulweb.app/api/v1/tools/equation-art-studio/calculate
- [Keyboard Heatmap Visualizer](https://keyboardheatmapvisualizer.usefulweb.app/): Paste any text: see which keys and fingers do the work on QWERTY, Dvorak, Colemak & co. API: POST https://usefulweb.app/api/v1/tools/keyboard-heatmap-visualizer/calculate
- [Movie & Series Marathon Planner](https://runtimemarathonplanner.usefulweb.app/): Plan a binge: when each movie or episode starts and ends, total days, and a calendar. API: POST https://usefulweb.app/api/v1/tools/runtime-marathon-planner/calculate
- [Movie Night Consensus Picker](https://movienightconsensuspicker.usefulweb.app/): Everyone ranks the films, vetoes count: Borda, approval, runoff and Condorcet decide. API: POST https://usefulweb.app/api/v1/tools/movie-night-consensus-picker/calculate
- [Padel & Pickleball Scheduler](https://padelpickleballscheduler.usefulweb.app/): Fair Americano or Mexicano doubles rounds with balanced sit-outs, scores and standings. API: POST https://usefulweb.app/api/v1/tools/padel-pickleball-scheduler/calculate
- [Password Entropy Race](https://passwordentropyrace.usefulweb.app/): Race 2–6 passwords or passphrases: entropy, pattern penalties and crack times. API: POST https://usefulweb.app/api/v1/tools/password-entropy-race/calculate
- [Regex Golf Arena](https://regexgolfarena.usefulweb.app/): Match the left list, avoid the right list — in as few characters as possible. API: POST https://usefulweb.app/api/v1/tools/regex-golf-arena/calculate
- [Sports What-If Simulator](https://sportswhatifsimulator.usefulweb.app/): Simulate a match or a small league with a Poisson goal model — and replay “what if”. API: POST https://usefulweb.app/api/v1/tools/sports-what-if-simulator/calculate
- [Tournament Bracket Maker](https://tournamentbracketmaker.usefulweb.app/): Single or double elimination or round robin: seeded brackets, byes, results and downloads. API: POST https://usefulweb.app/api/v1/tools/tournament-bracket-maker/calculate
- [Loan Amortization Calculator](https://loanamortizationcalculator.usefulweb.app/): Annuity, linear or interest-only loans: schedule, extra payments, fixed-rate balance, APR. API: POST https://usefulweb.app/api/v1/tools/loan-amortization-calculator/calculate
- [One-Rep-Max & Plate Loader](https://onerepmaxcalculator.usefulweb.app/): 1RM from any set (7 formulas + average), % and RPE tables, and which plates to load. API: POST https://usefulweb.app/api/v1/tools/one-rep-max-calculator/calculate
- [Percentage & Ratio Calculator](https://percentageratiocalculator.usefulweb.app/): X% of Y, % change, reverse %, percentage points, ratios and aspect ratios, with formulas. API: POST https://usefulweb.app/api/v1/tools/percentage-ratio-calculator/calculate
- [Random Generator](https://randomgenerator.usefulweb.app/): Random numbers, dice, coins, list picks, shuffles, fair teams, dates, strings and UUIDs. API: POST https://usefulweb.app/api/v1/tools/random-generator/calculate
- [Running Pace & Splits](https://runningpacecalculator.usefulweb.app/): Pace, time or distance in km or miles, splits, race predictions, treadmill speed, laps. API: POST https://usefulweb.app/api/v1/tools/running-pace-calculator/calculate
- [Sports Travel-Fatigue Estimator](https://sportstravelfatigueestimator.usefulweb.app/): Travel distance, time-zone jumps, rest and back-to-backs per game as a fatigue score. API: POST https://usefulweb.app/api/v1/tools/sports-travel-fatigue-estimator/calculate
- [Tip & Bill Split Calculator](https://tipbillsplitcalculator.usefulweb.app/): Tip, tax and who pays what: split a bill equally, by shares or by items, rounded up. API: POST https://usefulweb.app/api/v1/tools/tip-bill-split-calculator/calculate
- [Office to PDF Converter](https://officetopdfconverter.usefulweb.app/): Convert Word, Excel, PowerPoint, OpenDocument, RTF and CSV files to PDF with LibreOffice. API: POST https://usefulweb.app/api/v1/tools/office-to-pdf-converter/calculate
- [PDF ↔ Image Converter](https://pdfimageconverter.usefulweb.app/): Turn PDF pages into PNG or JPG images, or combine images into a PDF without quality loss. API: POST https://usefulweb.app/api/v1/tools/pdf-image-converter/calculate
- [PDF Compressor](https://pdfcompressor.usefulweb.app/): Make PDFs smaller with Ghostscript presets or custom image DPI and JPEG quality, with previews. API: POST https://usefulweb.app/api/v1/tools/pdf-compressor/calculate
- [PDF Form & Signature Studio](https://pdfformsignaturestudio.usefulweb.app/): List and fill PDF form fields, and place a visible signature image or typed name on a page. API: POST https://usefulweb.app/api/v1/tools/pdf-form-signature-studio/calculate
- [PDF Merge, Split & Reorder](https://pdfmergesplitreorder.usefulweb.app/): Merge PDFs, split by page count or ranges, and reorder, remove, rotate or duplicate pages. API: POST https://usefulweb.app/api/v1/tools/pdf-merge-split-reorder/calculate
- [Searchable PDF OCR](https://searchablepdfocr.usefulweb.app/): Make scanned PDFs searchable and copyable with OCRmyPDF and Tesseract, optionally as PDF/A. API: POST https://usefulweb.app/api/v1/tools/searchable-pdf-ocr/calculate
- [Secure PDF Redactor](https://securepdfredactor.usefulweb.app/): Black out names, numbers or areas in a PDF for real: the text is removed, not just covered. API: POST https://usefulweb.app/api/v1/tools/secure-pdf-redactor/calculate
- [Audio Cutter & Merger](https://audiocuttermerger.usefulweb.app/): Trim audio, keep or remove ranges, fade in/out, or join up to 10 clips with crossfades. API: POST https://usefulweb.app/api/v1/tools/audio-cutter-merger/calculate
- [Audio Loudness Normalizer](https://audioloudnessnormalizer.usefulweb.app/): Measure LUFS and true peak, then normalise to Spotify, podcast or EBU R 128 targets. API: POST https://usefulweb.app/api/v1/tools/audio-loudness-normalizer/calculate
- [Background Remover](https://backgroundremover.usefulweb.app/): Remove plain backgrounds from product photos and logos (colour-based, no AI) → transparent PNG. API: POST https://usefulweb.app/api/v1/tools/background-remover/calculate
- [Batch Image Resizer & Cropper](https://batchimageresizer.usefulweb.app/): Resize or crop up to 30 images at once: exact size, fit, percentage or 1:1, 4:5, 16:9, 9:16. API: POST https://usefulweb.app/api/v1/tools/batch-image-resizer/calculate
- [Batch Watermark Studio](https://batchwatermarkstudio.usefulweb.app/): Add a text or logo watermark to up to 30 images at once: position, tiling, opacity and angle. API: POST https://usefulweb.app/api/v1/tools/batch-watermark-studio/calculate
- [EXIF Inspector & Cleaner](https://exifinspectorcleaner.usefulweb.app/): See all photo metadata (EXIF, GPS, XMP, IPTC, MakerNotes) and download a cleaned copy. API: POST https://usefulweb.app/api/v1/tools/exif-inspector-cleaner/calculate
- [HEIC/RAW Image Converter](https://heicrawconverter.usefulweb.app/): Convert iPhone HEIC, AVIF and camera RAW (CR2, CR3, NEF, ARW, DNG…) to JPG, PNG or WebP. API: POST https://usefulweb.app/api/v1/tools/heic-raw-converter/calculate
- [Image Compressor](https://imagecompressor.usefulweb.app/): Shrink JPG, PNG, WebP, AVIF or GIF images: convert, resize, strip metadata and compare sizes. API: POST https://usefulweb.app/api/v1/tools/image-compressor/calculate
- [Image Upscaler](https://imageupscaler.usefulweb.app/): Enlarge images 2×, 3× or 4× with classic Lanczos/Mitchell filters and sharpening (no AI). API: POST https://usefulweb.app/api/v1/tools/image-upscaler/calculate
- [MP3 Tag & Cover Editor](https://mp3tagcovereditor.usefulweb.app/): Edit MP3 ID3 tags (title, artist, album, year…) and add, replace or remove the cover. API: POST https://usefulweb.app/api/v1/tools/mp3-tag-cover-editor/calculate
- [Subtitle Studio](https://subtitlestudio.usefulweb.app/): Convert SRT, VTT, ASS and SBV; shift, re-sync, fix overlaps, wrap lines and check CPS. API: POST https://usefulweb.app/api/v1/tools/subtitle-studio/calculate
- [SVG Optimizer](https://svgoptimizer.usefulweb.app/): Shrink and sanitise SVG files: strip editor junk and scripts, round numbers, minify paths. API: POST https://usefulweb.app/api/v1/tools/svg-optimizer/calculate
- [Universal Audio Converter](https://audioconverter.usefulweb.app/): Convert MP3, WAV, FLAC, Ogg, Opus, M4A and AIFF with bitrate and sample-rate control. API: POST https://usefulweb.app/api/v1/tools/audio-converter/calculate
- [Universal Video Converter](https://videoconverter.usefulweb.app/): Convert video to MP4, WebM, MOV or MKV: resize, set quality and fps, or remux losslessly. API: POST https://usefulweb.app/api/v1/tools/video-converter/calculate
- [Vertical Video Reframer](https://verticalvideoreframer.usefulweb.app/): Reframe video to 9:16, 1:1, 4:5 or 16:9 by cropping, a blurred background or bars. API: POST https://usefulweb.app/api/v1/tools/vertical-video-reframer/calculate
- [Video Compressor](https://videocompressor.usefulweb.app/): Shrink a video to a target size (two-pass) for e-mail, WhatsApp or Discord, or by quality. API: POST https://usefulweb.app/api/v1/tools/video-compressor/calculate
- [Video Cutter & Merger](https://videocuttermerger.usefulweb.app/): Trim video, remove a section or join clips: lossless copy or frame-exact re-encode. API: POST https://usefulweb.app/api/v1/tools/video-cutter-merger/calculate
- [Video to GIF Creator](https://videotogifcreator.usefulweb.app/): Turn a video clip into a high-quality GIF or animated WebP with fps, width and dithering. API: POST https://usefulweb.app/api/v1/tools/video-to-gif-creator/calculate
- [Video to MP3 Extractor](https://videotoaudioextractor.usefulweb.app/): Extract a video’s soundtrack as MP3, WAV or FLAC, or copy the original audio losslessly. API: POST https://usefulweb.app/api/v1/tools/video-to-audio-extractor/calculate
- [CSV/Excel Chart Studio](https://csvexcelchartstudio.usefulweb.app/): Turn CSV, TSV or Excel data into line, bar, pie, scatter or histogram charts with SVG/PNG export. API: POST https://usefulweb.app/api/v1/tools/csv-excel-chart-studio/calculate
- [Diagram & Flowchart Maker](https://diagramflowchartmaker.usefulweb.app/): Write flowcharts, sequence diagrams and mind maps as text and get a laid-out SVG/PNG diagram. API: POST https://usefulweb.app/api/v1/tools/diagram-flowchart-maker/calculate
- [Embeddable Chart Builder](https://embeddablechartbuilder.usefulweb.app/): Make a self-contained chart to embed anywhere: inline SVG, standalone HTML, accessible snippet. API: POST https://usefulweb.app/api/v1/tools/embeddable-chart-builder/calculate
- [Geo Data Visualizer](https://geodatavisualizer.usefulweb.app/): Map CSV coordinates or GeoJSON as points, proportional circles, hex-bin heatmaps or choropleths. API: POST https://usefulweb.app/api/v1/tools/geo-data-visualizer/calculate
- [Time-Series Explorer](https://timeseriesexplorer.usefulweb.app/): Resample, smooth and decompose date/value data: trend, R², seasonality, YoY change and anomalies. API: POST https://usefulweb.app/api/v1/tools/time-series-explorer/calculate
- [Big-O Crossover Calculator](https://bigocrossovercalculator.usefulweb.app/): When does c₁·n log n beat c₂·n²? Crossover points, log-log chart and run times. API: POST https://usefulweb.app/api/v1/tools/big-o-crossover-calculator/calculate
- [Erasure-Coding Playground](https://erasurecodingplayground.usefulweb.app/): Reed–Solomon over GF(256): encode data into k + m shards, lose some, rebuild it. API: POST https://usefulweb.app/api/v1/tools/erasure-coding-playground/calculate
- [Floating-Point Explorer](https://floatingpointexplorer.usefulweb.app/): See how IEEE-754 half/single/double store a number: bits, exact value, ULP, rounding error. API: POST https://usefulweb.app/api/v1/tools/floating-point-explorer/calculate
- [Graph Algorithm Visualizer](https://graphalgorithmvisualizer.usefulweb.app/): BFS, DFS, Dijkstra, Bellman–Ford, A*, MST, topological sort and SCCs on your edge list. API: POST https://usefulweb.app/api/v1/tools/graph-algorithm-visualizer/calculate
- [Graphing Calculator](https://graphingcalculator.usefulweb.app/): Plot up to 6 functions or parametric curves with roots, extrema, intersections and SVG/PNG export. API: POST https://usefulweb.app/api/v1/tools/graphing-calculator/calculate
- [Math Workbench](https://mathworkbench.usefulweb.app/): Simplify, factor, differentiate, integrate, solve, take limits, series and plots in one box. API: POST https://usefulweb.app/api/v1/tools/math-workbench/calculate
- [Matrix & Linear Algebra Lab](https://matrixlinearalgebralab.usefulweb.app/): Exact-fraction RREF with steps, determinant, inverse, null space, eigenvalues, LU/QR and Ax = b. API: POST https://usefulweb.app/api/v1/tools/matrix-linear-algebra-lab/calculate
- [Number-Theory Lab](https://numbertheorylab.usefulweb.app/): Primality, factorisation, gcd, modular arithmetic, CRT, φ, π(n), Collatz, continued fractions. API: POST https://usefulweb.app/api/v1/tools/number-theory-lab/calculate
- [Probability & Statistics Studio](https://probabilitystatisticsstudio.usefulweb.app/): Distributions, descriptive stats, confidence intervals and t, chi-square and z tests with p-values. API: POST https://usefulweb.app/api/v1/tools/probability-statistics-studio/calculate
- [Step-by-Step Equation Solver](https://equationsolversteps.usefulweb.app/): Solve linear, quadratic, rational and radical equations or linear systems with every step shown. API: POST https://usefulweb.app/api/v1/tools/equation-solver-steps/calculate
- [Crypto Kitchen](https://cryptokitchen.usefulweb.app/): CyberChef-style recipes: chain encodings, compression, hashes, AES, JWT and more, step by step. API: POST https://usefulweb.app/api/v1/tools/crypto-kitchen/calculate
- [Hash & HMAC Calculator](https://hashhmaccalculator.usefulweb.app/): MD5, SHA-2, SHA-3, BLAKE2, CRC32 and HMAC of text or files, with checksum compare. API: POST https://usefulweb.app/api/v1/tools/hash-hmac-calculator/calculate
- [Key Derivation Lab](https://keyderivationlab.usefulweb.app/): Derive keys with PBKDF2, scrypt, Argon2id and HKDF; compare costs with OWASP advice. API: POST https://usefulweb.app/api/v1/tools/key-derivation-lab/calculate
- [Local File Encryption Studio](https://fileencryptionstudio.usefulweb.app/): Encrypt and decrypt files with AES-256-GCM and a password, locally in your browser. API: POST https://usefulweb.app/api/v1/tools/file-encryption-studio/calculate
- [Password & Passphrase Generator](https://passwordgenerator.usefulweb.app/): Strong random passwords and passphrases, made in your browser, with exact entropy. API: POST https://usefulweb.app/api/v1/tools/password-generator/calculate
- [Private Breach Checker](https://privatebreachchecker.usefulweb.app/): Check if a password appears in known breaches without revealing it (k-anonymity). API: POST https://usefulweb.app/api/v1/tools/private-breach-checker/calculate
- [RSA/ECC Key Inspector](https://rsaecckeyinspector.usefulweb.app/): Inspect PEM, DER, JWK or OpenSSH keys: type, size, curve, fingerprints, thumbprint and weaknesses. API: POST https://usefulweb.app/api/v1/tools/rsa-ecc-key-inspector/calculate
- [Shamir Secret Sharing](https://shamirsecretsharing.usefulweb.app/): Split a secret into n shares so any k recover it, and combine shares, locally. API: POST https://usefulweb.app/api/v1/tools/shamir-secret-sharing/calculate
- [TLS Cipher-Suite Simulator](https://tlsciphersuitesimulator.usefulweb.app/): See which TLS version, cipher and group browsers, Android, Java and OpenSSL get from your server. API: POST https://usefulweb.app/api/v1/tools/tls-cipher-suite-simulator/calculate
- [X.509 / ASN.1 Certificate Inspector](https://x509certificateinspector.usefulweb.app/): Decode X.509 certificates, chains and CSRs: SANs, usages, CT SCTs, chain order and an ASN.1 tree. API: POST https://usefulweb.app/api/v1/tools/x509-certificate-inspector/calculate
- [Animation Exposure Sheet](https://fliplineexposuresheet.usefulweb.app/): Turn drawing holds into a precise animation timing sheet. API: POST https://usefulweb.app/api/v1/tools/flipline-exposure-sheet/calculate
- [Animation Motion Study Generator](https://fliplinemotionstudy.usefulweb.app/): Generate an editable flipbook to compare animation easing curves. API: POST https://usefulweb.app/api/v1/tools/flipline-motion-study/calculate
- [Image Grid Splitter](https://luminaimagesplitter.usefulweb.app/): Slice a photo into numbered tiles without losing edge pixels. API: POST https://usefulweb.app/api/v1/tools/lumina-image-splitter/calculate
- [Image Shape Mask & Feather](https://luminaimagemask.usefulweb.app/): Clip a photo into a soft rectangle or ellipse with PNG transparency. API: POST https://usefulweb.app/api/v1/tools/lumina-image-mask/calculate
- [Kerfwise Cabinet Builder](https://kerfwisecabinetbuilder.usefulweb.app/): Parametric cabinet → every part with cut sizes, edge banding, drilling and hardware. API: POST https://usefulweb.app/api/v1/tools/kerfwise-cabinet-builder/calculate
- [Kerfwise CNC G-code Generator](https://apps.usefulweb.app/tools/kerfwise-cnc-gcode/): Nest parts and get CNC router G-code: compensated profiles, tabs, ramps, drilling cycles, time. API: POST https://usefulweb.app/api/v1/tools/kerfwise-cnc-gcode/calculate
- [Kerfwise Cut List & Cost](https://kerfwisecutlist.usefulweb.app/): Cabinets or a Kerfwise project → cut list, edge banding, hardware, sheets and costs. API: POST https://usefulweb.app/api/v1/tools/kerfwise-cut-list/calculate
- [Kerfwise Sheet Nesting Optimizer](https://kerfwisesheetnesting.usefulweb.app/): Nest rectangular and shaped parts on sheets: kerf, grain, yield, lower bound, offcuts, SVG + DXF. API: POST https://usefulweb.app/api/v1/tools/kerfwise-sheet-nesting/calculate
- [Kinetica Collision Check](https://kineticacollisioncheck.usefulweb.app/): Robot pose + obstacles → collisions, minimum clearance and self-collision between links. API: POST https://usefulweb.app/api/v1/tools/kinetica-collision-check/calculate
- [Kinetica Forward Kinematics](https://kineticaforwardkinematics.usefulweb.app/): DH table or URDF + joint values → TCP pose, every joint frame, Jacobian and manipulability. API: POST https://usefulweb.app/api/v1/tools/kinetica-forward-kinematics/calculate
- [Kinetica Inverse Kinematics](https://kineticainversekinematics.usefulweb.app/): Target TCP pose → all joint solutions found, residuals, joint limits and reachability. API: POST https://usefulweb.app/api/v1/tools/kinetica-inverse-kinematics/calculate
- [Kinetica Trajectory Planner](https://kineticatrajectoryplanner.usefulweb.app/): Waypoints (PTP, LIN, CIRC) + limits → timed joint samples, cycle time and peak velocities. API: POST https://usefulweb.app/api/v1/tools/kinetica-trajectory-planner/calculate
- [Layer Blend Color Mixer](https://luminablendmixer.usefulweb.app/): Preview eight blend modes and opacity for two opaque colors. API: POST https://usefulweb.app/api/v1/tools/lumina-blend-mixer/calculate
- [Layer Transform & Bounds Planner](https://luminalayertransform.usefulweb.app/): Calculate a layer transform, rotated corners and canvas bounds. API: POST https://usefulweb.app/api/v1/tools/lumina-layer-transform/calculate
- [Ohmforge AC Sweep (Bode plot)](https://ohmforgeacsweep.usefulweb.app/): Frequency response of a circuit: Bode magnitude/phase, −3 dB corner and unity gain. API: POST https://usefulweb.app/api/v1/tools/ohmforge-ac-sweep/calculate
- [Ohmforge DC Operating Point](https://ohmforgedcoperatingpoint.usefulweb.app/): SPICE netlist in, node voltages, branch currents, power and overload warnings out. API: POST https://usefulweb.app/api/v1/tools/ohmforge-dc-operating-point/calculate
- [Ohmforge LED Resistor Calculator](https://ohmforgeledresistor.usefulweb.app/): Series resistor for LEDs, rounded to a standard value and checked with a real diode model. API: POST https://usefulweb.app/api/v1/tools/ohmforge-led-resistor/calculate
- [Ohmforge Transient Simulation](https://ohmforgetransient.usefulweb.app/): Simulate a circuit over time: waveforms, Vpp/RMS/frequency, CSV and a chart. API: POST https://usefulweb.app/api/v1/tools/ohmforge-transient/calculate
- [Photo Collage & Image Joiner](https://luminaphotolayout.usefulweb.app/): Make a photo grid or join photos horizontally and vertically. API: POST https://usefulweb.app/api/v1/tools/lumina-photo-layout/calculate
- [Photo Crop & Resize Planner](https://luminaresizeplanner.usefulweb.app/): Plan a precise crop and output size before resizing a photo. API: POST https://usefulweb.app/api/v1/tools/lumina-resize-planner/calculate
- [Photo Histogram & Clipping Analyzer](https://luminahistogramanalyzer.usefulweb.app/): Inspect RGB histograms, clipped channels and tonal percentiles in a photo. API: POST https://usefulweb.app/api/v1/tools/lumina-histogram-analyzer/calculate
- [Photo Palette & Text Contrast](https://luminacoloranalyzer.usefulweb.app/): Check palette luminance and choose readable text for photos and graphics. API: POST https://usefulweb.app/api/v1/tools/lumina-color-analyzer/calculate
- [Photo Print Size Planner](https://luminaprintplanner.usefulweb.app/): Find how large your photo can print at your chosen resolution. API: POST https://usefulweb.app/api/v1/tools/lumina-print-planner/calculate
- [Photo to Animated GIF](https://luminagifmaker.usefulweb.app/): Turn an ordered set of photos into a looping animated GIF. API: POST https://usefulweb.app/api/v1/tools/lumina-gif-maker/calculate
- [Photo Tone Curves & Profile Processor](https://luminatoneprocessor.usefulweb.app/): Apply levels, RGB curves and white balance, or reuse a Lumina photo profile. API: POST https://usefulweb.app/api/v1/tools/lumina-tone-processor/calculate
- [Pixel Art Image Converter](https://fliplinepixelquantizer.usefulweb.app/): Convert images into pixel art with palettes, dithering and retro effects. API: POST https://usefulweb.app/api/v1/tools/flipline-pixel-quantizer/calculate
- [Pixel Grid Transform](https://fliplinepixeltransform.usefulweb.app/): Flip, rotate or shift an indexed pixel sprite without blur. API: POST https://usefulweb.app/api/v1/tools/flipline-pixel-transform/calculate
- [Pixel Palette Format Converter](https://fliplinepaletteconverter.usefulweb.app/): Convert HEX, GIMP GPL and JASC-PAL palettes without changing color order. API: POST https://usefulweb.app/api/v1/tools/flipline-palette-converter/calculate
- [Retro Pixel Art Batch Processor](https://fliplineretrobatch.usefulweb.app/): Apply one retro palette and effect recipe to a ZIP of images. API: POST https://usefulweb.app/api/v1/tools/flipline-retro-batch/calculate
- [Sprite Sheet Layout Planner](https://fliplinespritesheet.usefulweb.app/): Plan an animation atlas with exact frame rectangles and padding. API: POST https://usefulweb.app/api/v1/tools/flipline-sprite-sheet/calculate
- [Threadsmith Design Stats](https://threadsmithdesignstats.usefulweb.app/): Stitch count, colours, trims, thread, bobbin, sewing time and density of a DST/EXP file. API: POST https://usefulweb.app/api/v1/tools/threadsmith-design-stats/calculate
- [Threadsmith Digitizer](https://threadsmithdigitize.usefulweb.app/): Turn shapes, SVG paths, text or a whole project into embroidery stitches with stats and preview. API: POST https://usefulweb.app/api/v1/tools/threadsmith-digitize/calculate
- [Threadsmith Stitch File Writer](https://threadsmithstitchfile.usefulweb.app/): Write Tajima DST or Melco EXP machine files from a stitch list or a Threadsmith project. API: POST https://usefulweb.app/api/v1/tools/threadsmith-stitch-file/calculate
- [Twinworks Bottleneck Analysis](https://twinworksbottleneckanalysis.usefulweb.app/): Find the constraint of a production line and test fixes: ranked bottlenecks with what-if gains. API: POST https://usefulweb.app/api/v1/tools/twinworks-bottleneck-analysis/calculate
- [Twinworks Buffer & Parameter Sweep](https://twinworksbuffersweep.usefulweb.app/): Sweep a buffer size (or any parameter) and get the throughput curve with confidence intervals. API: POST https://usefulweb.app/api/v1/tools/twinworks-buffer-sweep/calculate
- [Twinworks Factory Simulation](https://twinworkssimulate.usefulweb.app/): Simulate a production line: throughput, lead time, WIP, OEE and the bottleneck, with CIs. API: POST https://usefulweb.app/api/v1/tools/twinworks-simulate/calculate
- [Twinworks Line Balancing](https://twinworkslinebalance.usefulweb.app/): Assign assembly tasks to stations for a takt time: efficiency, balance delay and smoothness index. API: POST https://usefulweb.app/api/v1/tools/twinworks-line-balance/calculate
- [Twinworks Queueing Check](https://twinworksqueueformulas.usefulweb.app/): M/M/1, M/M/c, M/D/1, M/G/1 and Kingman waiting times — optionally verified by simulation. API: POST https://usefulweb.app/api/v1/tools/twinworks-queue-formulas/calculate

## Workflows
- [Moving home](https://usefulweb.app/workflows/moving-home): Personalised moving checklist with deadlines, box and van estimate, an optional "will the sofa fit?" check, and a maintenance calendar for the new place. Steps: life-admin-generator → moving-box-planner → will-it-fit → household-maintenance-calendar. API: POST https://usefulweb.app/api/v1/workflows/moving-home/run
- [Is this message a scam?](https://usefulweb.app/workflows/suspicious-message): Analyses a suspicious e-mail/SMS for scam signals, then checks the reachability and security headers of the linked website. Never claims a message is safe. Steps: scam-signal-checker → headerlens. API: POST https://usefulweb.app/api/v1/workflows/suspicious-message/run
- [Subscription clean-up](https://usefulweb.app/workflows/subscription-cleanup): Totals your subscriptions, flags overlaps and poor value, and gives verified cancellation steps for the one you want to cancel first. Steps: subscription-stack → cancellation-navigator. API: POST https://usefulweb.app/api/v1/workflows/subscription-cleanup/run

## Premium apps
Full, free programs that run in the browser (local-first, no sign-up). Each has a landing page, a workspace at /app, tutorials, a documented project file format (/project.schema.json) and its deterministic engine exposed as tools (API + MCP on the app's own host).
- [Kerfwise](https://kerfwise.usefulweb.app/) – Cabinet & furniture CAD: Design cabinets and furniture, get cut lists, optimised sheet layouts, costs and drawings. Workspace: https://kerfwise.usefulweb.app/app · project schema: https://kerfwise.usefulweb.app/project.schema.json · MCP: https://kerfwise.usefulweb.app/mcp · engine tools: `kerfwise_cabinet_builder`, `kerfwise_cut_list`, `kerfwise_sheet_nesting`, `kerfwise_cnc_gcode`
- [Kinetica](https://kinetica.usefulweb.app/) – Robot motion studio: Simulate robot arms in your browser: kinematics, trajectories, collisions, program export. Workspace: https://kinetica.usefulweb.app/app · project schema: https://kinetica.usefulweb.app/project.schema.json · MCP: https://kinetica.usefulweb.app/mcp · engine tools: `kinetica_forward_kinematics`, `kinetica_inverse_kinematics`, `kinetica_trajectory_planner`, `kinetica_collision_check`
- [Threadsmith](https://threadsmith.usefulweb.app/) – Embroidery digitizing studio: Draw or import artwork, turn it into real stitches, and export DST/EXP for your machine. Workspace: https://threadsmith.usefulweb.app/app · project schema: https://threadsmith.usefulweb.app/project.schema.json · MCP: https://threadsmith.usefulweb.app/mcp · engine tools: `threadsmith_digitize`, `threadsmith_stitch_file`, `threadsmith_design_stats`
- [Ohmforge](https://ohmforge.usefulweb.app/) – Virtual electronics workbench: Draw a circuit, switch it on, and measure it with real-feeling bench instruments. Workspace: https://ohmforge.usefulweb.app/app · project schema: https://ohmforge.usefulweb.app/project.schema.json · MCP: https://ohmforge.usefulweb.app/mcp · engine tools: `ohmforge_dc_operating_point`, `ohmforge_transient`, `ohmforge_ac_sweep`, `ohmforge_led_resistor`
- [Twinworks](https://twinworks.usefulweb.app/) – Factory digital twin & production simulation: Model a production line, simulate it and find the bottleneck — free, in your browser. Workspace: https://twinworks.usefulweb.app/app · project schema: https://twinworks.usefulweb.app/project.schema.json · MCP: https://twinworks.usefulweb.app/mcp · engine tools: `twinworks_simulate`, `twinworks_bottleneck_analysis`, `twinworks_line_balance`, `twinworks_buffer_sweep`, `twinworks_queue_formulas`
- [Flipline](https://flipline.usefulweb.app/) – Drawing, pixel art & animation: A few drawings. A little life. Make a flipbook in your browser. Workspace: https://flipline.usefulweb.app/app · project schema: https://flipline.usefulweb.app/project.schema.json · MCP: https://flipline.usefulweb.app/mcp · engine tools: `flipline_exposure_sheet`, `flipline_sprite_sheet`, `flipline_motion_study`, `flipline_pixel_quantizer`, `flipline_pixel_transform`, `flipline_palette_converter`, `flipline_retro_batch`
- [Lumina](https://lumina.usefulweb.app/) – Photo editor & image toolkit: Bring out what you saw. A free photo studio, right in your browser. Workspace: https://lumina.usefulweb.app/app · project schema: https://lumina.usefulweb.app/project.schema.json · MCP: https://lumina.usefulweb.app/mcp · engine tools: `lumina_resize_planner`, `lumina_print_planner`, `lumina_color_analyzer`, `lumina_photo_layout`, `lumina_image_splitter`, `lumina_gif_maker`, `lumina_layer_transform`, `lumina_blend_mixer`, `lumina_image_mask`, `lumina_histogram_analyzer`, `lumina_tone_processor`