API & MCP

Everything a person can do on usefulweb.app, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

• GET https://usefulweb.app/api/v1/tools – catalog
• GET https://usefulweb.app/api/v1/tools/{id} – inputs, output schema, examples
• POST https://usefulweb.app/api/v1/tools/{id}/calculate – run a tool
• GET https://usefulweb.app/api/v1/workflows · POST https://usefulweb.app/api/v1/workflows/{id}/run
• OpenAPI 3.1: /openapi.json · /openapi.yaml
• Errors: application/problem+json; 422 includes per-field errors.

Every result contains

inputs (normalised, defaults applied), summary, result (validated against the published schema), units, assumptions, sources, warnings, computedAt and links.

MCP (Model Context Protocol)

• Streamable HTTP endpoint: https://usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
• Tools: headerlens, cancellation_navigator, deadline_decoder, decision_simulator, form_translator, how_long_will_it_last, is_it_worth_it, life_admin_generator, repair_or_replace, true_cost_calculator, bill_detective, break_even_explorer, bulk_buy_brain, currency_converter, hidden_fee_finder, historical_fx_chart, inflation_time_machine, multi_currency_invoice_calculator, price_per_everything, salary_reality_check, subscription_stack, travel_exchange_fee_calculator, warranty_value_calculator, food_storage_guide, household_chore_rotator, household_maintenance_calendar, jet_lag_planner, leftover_chef, moving_box_planner, room_layout_optimizer, travel_connection_checker, weekly_meal_planner, will_it_fit, ai_answer_verifier, error_message_translator, file_format_doctor, privacy_policy_decoder, prompt_to_tool_router, scam_signal_checker, screenshot_to_steps, website_change_explainer, accessibility_fixer, before_you_sign, digital_estate_organizer, disaster_prep_builder, compatibility_engine, what_changed_in_this_law, a11y_snapshot, browser_compatibility_checker, citeshape, cyberchef_lite_pipeline, datafresh, filefit, localekit, network_speed_tester, ruledate, safe_markdown_preview, timefair, unicode_inspector, unitproof, unix_permission_calculator, account_abstraction_explorer, blockchain_incident_replay, bridge_transfer_tracker, cross_chain_transaction_explorer, dao_governance_explorer, defi_liquidation_explorer, gas_fee_intelligence_explorer, mev_explorer, rollup_batch_explorer, smart_contract_relationship_graph, contract_upgrade_explorer, stablecoin_flow_explorer, token_unlock_explorer, transaction_decoder, wallet_permission_explorer, asn_relationship_explorer, bgp_route_explorer, cdn_behavior_explorer, certificate_transparency_explorer, dns_certificate_explorer, domain_history_graph, email_infrastructure_explorer, global_dns_explorer, http_technology_explorer, internet_outage_atlas, ipv6_readiness_explorer, artifact_provenance_explorer, c2pa_credentials_inspector, container_image_explorer, cve_relationship_graph, dependency_vulnerability_explorer, oauth_permission_explorer, open_source_trust_explorer, package_ecosystem_graph, passkey_webauthn_tester, sbom_explorer, sbom_license_checker, security_advisory_timeline, security_configuration_scanner, api_explorer_of_explorers, cicd_failure_explorer, cron_job_explorer, data_lineage_explorer, distributed_trace_explorer, kubernetes_event_explorer, openapi_diff_explorer, query_plan_visualizer, serverless_performance_explorer, terraform_drift_explorer, agent_permission_graph, ai_agent_tool_explorer, ai_model_compatibility_explorer, tool_call_trace_explorer, ai_website_readiness_explorer, llm_cost_explorer, mcp_server_explorer, model_behavior_regression_explorer, rag_citation_debugger, structured_output_validator, energy_grid_explorer, internet_archive_change_explorer, public_spending_explorer, satellite_change_explorer, software_adoption_explorer, explore, chore_roulette, elo_glicko_rating_lab, emoji_cipher_playground, equation_art_studio, keyboard_heatmap_visualizer, runtime_marathon_planner, movie_night_consensus_picker, padel_pickleball_scheduler, password_entropy_race, regex_golf_arena, sports_what_if_simulator, tournament_bracket_maker, loan_amortization_calculator, one_rep_max_calculator, percentage_ratio_calculator, random_generator, running_pace_calculator, sports_travel_fatigue_estimator, tip_bill_split_calculator, office_to_pdf_converter, pdf_image_converter, pdf_compressor, pdf_form_signature_studio, pdf_merge_split_reorder, searchable_pdf_ocr, secure_pdf_redactor, audio_cutter_merger, audio_loudness_normalizer, background_remover, batch_image_resizer, batch_watermark_studio, exif_inspector_cleaner, heic_raw_converter, image_compressor, image_upscaler, mp3_tag_cover_editor, subtitle_studio, svg_optimizer, audio_converter, video_converter, vertical_video_reframer, video_compressor, video_cutter_merger, video_to_gif_creator, video_to_audio_extractor, csv_excel_chart_studio, diagram_flowchart_maker, embeddable_chart_builder, geo_data_visualizer, time_series_explorer, big_o_crossover_calculator, erasure_coding_playground, floating_point_explorer, graph_algorithm_visualizer, graphing_calculator, math_workbench, matrix_linear_algebra_lab, number_theory_lab, probability_statistics_studio, equation_solver_steps, crypto_kitchen, hash_hmac_calculator, key_derivation_lab, file_encryption_studio, password_generator, private_breach_checker, rsa_ecc_key_inspector, shamir_secret_sharing, tls_cipher_suite_simulator, x509_certificate_inspector, flipline_exposure_sheet, flipline_motion_study, lumina_image_splitter, lumina_image_mask, kerfwise_cabinet_builder, kerfwise_cnc_gcode, kerfwise_cut_list, kerfwise_sheet_nesting, kinetica_collision_check, kinetica_forward_kinematics, kinetica_inverse_kinematics, kinetica_trajectory_planner, lumina_blend_mixer, lumina_layer_transform, ohmforge_ac_sweep, ohmforge_dc_operating_point, ohmforge_led_resistor, ohmforge_transient, lumina_photo_layout, lumina_resize_planner, lumina_histogram_analyzer, lumina_color_analyzer, lumina_print_planner, lumina_gif_maker, lumina_tone_processor, flipline_pixel_quantizer, flipline_pixel_transform, flipline_palette_converter, flipline_retro_batch, flipline_sprite_sheet, threadsmith_design_stats, threadsmith_digitize, threadsmith_stitch_file, twinworks_bottleneck_analysis, twinworks_buffer_sweep, twinworks_simulate, twinworks_line_balance, twinworks_queue_formulas, workflow_moving_home, workflow_suspicious_message, workflow_subscription_cleanup
• Local stdio connector: node src/mcp-stdio.ts

{
  "mcpServers": {
    "usefulweb": { "type": "http", "url": "https://usefulweb.app/mcp" }
  }
}