OpenAPI Spec Directory

Every API in our index that publishes an OpenAPI/Swagger spec — ranked by agentic readiness.

4191
Sites Indexed
35
Avg Score
498 entries in this directory
LLM Pulse — All-in-One AI Search Visibility & Reputation Platform
llmpulse.ai
LLM Pulse is your radar in the world of generative AI. Track your key prompts over time and see how AI sources are referencing your brand.
llms.txt OpenAPI API Schema.org ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
A
PanchangaAPI — The Deepest Vedic Astrology Engine. Built for Machines.
api.moon-bot.cc
32 tools. Swiss Ephemeris precision. MCP-ready. Pay $0.03/call with NOWPayments crypto or Telegram Stars. The deepest Vedic astrology API for AI agents and developers.
ai-plugin OpenAPI API MCP data
65
+20 ai-plugin +20 OpenAPI missing +25 llms.txt
UtilsForAgents — AI Agent Utility API | x402 Pay-Per-Call
utilsforagents.com
Pay-per-call AI agent utilities plus a free feedback endpoint: JSON diff, EXIF extraction, metadata scrubbing, HTML-to-Markdown, URL fetching, and feature-request collection. $0.003/call for paid utility routes via x402 on Base or Solana.
llms.txt OpenAPI API AI bots ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Fathom Analytics: A Better Google Analytics Alternative
usefathom.com
Ditch complex, intrusive analytics for Fathom - a better Google analytics alternative. Experience ease of use, forever data retention & full legal compliance.
llms.txt OpenAPI API Schema.org security
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Unmarkdown™ - Markdown Converter & Publishing Platform
unmarkdown.com
AI tools output markdown. Your apps don't understand it. We fix that instantly. Convert markdown to perfectly formatted text for Google Docs, Email, Word, Slack, OneNote, and more.
llms.txt OpenAPI API Schema.org developer
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
unulu™ — Create Link-in-Bio Sites via AI, MCP, or API
unulu.ai
Build and publish a link-in-bio page in seconds. Talk to any AI agent — Claude, ChatGPT, Gemini — and get a live site on unu.lu. Free, no signup. MCP server and REST API for developers.
llms.txt OpenAPI API Schema.org developer
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
PropertyScoop - More Facts, Fewer Surprises
propertyscoop.us
Power lines, wetlands, noise, natural light, privacy, schools, neighborhood, facing, digital TV coverage, celltower radiation, radon gas, wildfire, flooding, natural hazard risks, toxic cleanup sites, underground storage tanks, slope, crime, sex offenders, zoning code, permit history and more details.
llms.txt OpenAPI AI bots Schema.org MCP data
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
picoads — sponsored recommendations for AI agents
picoads.xyz
llms.txt OpenAPI API AI bots ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
A
AgentBroker — Trade Every Meme Coin. Purpose-Built for AI Agents.
agentbroker.polsia.app
Your AI agent's crypto exchange. 50+ pairs including every pump.fun meme coin. New tokens listed in seconds. No KYC, no browser — pure machine-native API access.
ai-plugin OpenAPI API MCP ai-tools
65
+20 ai-plugin +20 OpenAPI missing +25 llms.txt
Desearch - Live Search APIs for AI Agents
desearch.ai
Connect AI agents to live web search, AI summaries, clean crawl extraction, and real-time X data through one developer-friendly API layer.
llms.txt OpenAPI API AI bots ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
The Gold Standard of Fixed Income Math | Standard Securities Calculation Methods (SSCMFI)
api.sscmfi.com
Standard Securities Calculation Methods (SSCMFI) RESTful APIs and MCP Server. Industry-standard bond math for quants, developers, and AI agents.
llms.txt OpenAPI API Schema.org data
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Monarch Initiative
monarchinitiative.org
The Monarch Initiative integrates, aligns, and re-distributes cross-species gene, genotype, variant, disease, and phenotype data.
llms.txt OpenAPI API Schema.org health
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
BizToc
biztoc.com
The Entire Business World on a Single Page with the Web's Most Comprehensive One-Stop Finance News Hub.
ai-plugin OpenAPI API AI bots Schema.org news
65
+20 ai-plugin +20 OpenAPI missing +25 llms.txt
AgentMail | Email Inbox API for AI Agents
agentmail.to
AgentMail gives AI agents real email inboxes. Create, send, receive, and search messages via REST API — built for autonomous agents and agentic workflows.
llms.txt OpenAPI API Schema.org ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Tianji = Website Analytics + Uptime Monitor + Server Status | Tianji
tianji.msgbyte.com
All-in-One Insight Hub. Tianji = Website Analytics + Uptime Monitor + Server Status
llms.txt OpenAPI API Schema.org developer
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
LLMrefs - Generative AI Search Analytics - LLM SEO Tracker
llmrefs.com
Track brand visibility, rank, citations. Benchmark competitors & optimize for keywords across ChatGPT, AI Overviews, Perplexity, Claude, Gemini + more generative answer engines
llms.txt OpenAPI API Schema.org ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Welcome to Val Town | Docs | Val Town
docs.val.town
Deploy agents, APIs, static sites, apps, and crons with JavaScript
llms.txt OpenAPI API AI bots developer
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Healthcare Data APIs for Agents and Apps | FHIRfly
fhirfly.io
llms.txt OpenAPI API Schema.org health
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
B2B Company Data Enrichment and Contact Emails | DataMerge
datamerge.ai
Enrich B2B leads with verified company data and contact emails. 375M+ companies, 20+ data providers combined. Pay-as-you-go from $15/month.
llms.txt OpenAPI API Schema.org ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Certman - Certificate Authority That Scales
certman.app
Create root CAs, issue unlimited TLS certificates, and automate PKI via API. PKI for any scale, from home lab to business of any size.
llms.txt OpenAPI API Schema.org security
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Open Source Chart Image API | QuickChart
quickchart.io
Create a chart image with one API call and embed it anywhere. Send charts in email and other platforms. Open source, no watermarks, used by thousands of developers.
llms.txt ai-plugin OpenAPI developer
65
+25 llms.txt +20 ai-plugin missing +15 structured API
Inlay — Get Inlaid Into AI Answers
inlay.dev
SEO gets you into search results. Inlay gets you into AI answers. Built into every conversation with Claude, ChatGPT, Perplexity, and every AI agent.
llms.txt OpenAPI AI bots Schema.org MCP ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
VAT Sense - Free UK & EU VAT Number Validation API, EU VAT rates API
vatsense.com
VAT number validation API for UK, EU and worldwide. Global VAT and GST rates API, currency conversion, invoicing API. Trusted by thousands. Free plan available.
llms.txt OpenAPI API AI bots finance
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Sellm - AI Search Tracker | Monitor Your Brand on ChatGPT, Perplexity & Claude
sellm.io
Track your brand visibility across AI search engines. Monitor mentions on ChatGPT, Perplexity, Claude, Gemini & Grok. Get actionable insights for Generative Engine Optimization (GEO).
llms.txt OpenAPI API Schema.org ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
RAE API - Diccionario RAE
rae-api.com
API no oficial del diccionario de la Real Academia Española
llms.txt OpenAPI API Schema.org developer
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
I
402 Index
402index.io
Protocol-agnostic directory of paid APIs (L402, x402, MPP) for AI agents. Indexed, verified, and searchable.
llms.txt OpenAPI API Schema.org ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
D
docs.perplexity.ai
docs.perplexity.ai
llms.txt OpenAPI API AI bots ai-tools
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
ReqRes | Free REST API for developers | ReqRes
reqres.in
Free REST API for testing and prototyping with real responses, no signup needed. Or build your own backend with collections, auth, and logs at app.reqres.in.
llms.txt OpenAPI API Schema.org developer
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
QuizAPI - Developer-First Quiz Platform
quizapi.io
Create, share, and embed quizzes with a powerful REST API. AI-powered quiz generation, leaderboards, and gamification built in.
llms.txt OpenAPI API Schema.org education
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin
Real-Time API for Public Social Data — Affordable, No Limits
twitterapi.io
Affordable real-time API for public social data. Read user feeds, search posts, and publish with predictable per-call pricing — no minimums, no rate limits.
llms.txt OpenAPI API Schema.org security
65
+25 llms.txt +20 OpenAPI missing +20 ai-plugin

Wire NHS into your agent — MCP server

Add Not Human Search as an MCP tool. Your agent can call search_agents, get_site_details, get_stats, and submit_site at runtime.

Claude Code
claude mcp add --transport http nothumansearch https://nothumansearch.ai/mcp
Other clients: point any MCP-compatible tool at https://nothumansearch.ai/mcp (streamable-http transport).

Use NHS via REST

Prefer plain HTTP? Hit the search endpoint directly.

Search API
curl "https://nothumansearch.ai/api/v1/search?q=payment+API"
Agent Docs
llms.txt OpenAPI spec ai-plugin.json

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