Polski · HTML · llms.txt · catalog.json

AI Agents Accessible APIs

A curated, machine-readable encyclopedia of third-party APIs and MCP servers that AI agents can call on a user's behalf.

This article is about services an AI agent can operate programmatically, not AI products used by humans through a web UI.

AI Agents Accessible APIs is an open, bilingual (English/Polish) catalog of 331 services (each with a last-checked date) in 29 categories that an autonomous AI agent — such as Claude, ChatGPT, Gemini or a custom LLM agent — can use without a human in the loop, after a one-time human step: registering an account and handing the agent an API key, an OAuth token, or a connection to an MCP (Model Context Protocol) server. Every entry records the documentation URL, the authentication method, the availability of an official or community MCP server, and the free tier. The list is not a directory of products with “AI” in their name; the criterion is agent operability, not branding.

Contents

1. Machine-readable access (for AI agents)
2. Inclusion criteria
3. Legend
4. Web search (14) · Web scraping and browser automation (18) · Knowledge and research data (16) · Image generation and editing (10) · Video generation and editing (14) · Speech and audio (13) · Music generation (6) · 3D generation and assets (6) · Architecture, CAD and BIM (8) · Diagrams and software architecture (8) · Design and UI (6) · Documents, OCR and presentations (14) · Translation and language (6) · Code execution sandboxes (10) · Developer platforms and DevOps (12) · Cloud and hosting (10) · Databases (12) · Vector search, memory and RAG (9) · Email, team chat and notifications (10) · SMS and messaging apps (10) · Voice agents and telephony (9) · Productivity and workspace (17) · CRM, support and marketing (8) · Social media (10) · Maps, geolocation and weather (18) · Finance, payments and market data (16) · E-commerce (8) · Automation and integration platforms (15) · Model APIs and inference (18)
5. Related directories and registries
6. Contributing
7. See also
8. References

Machine-readable access (for AI agents)

AI agents should not parse this page. Fetch one of these stable files instead:

Recommended agent workflow: (1) pick the category file, (2) filter by auth and mcp.type, (3) read docs (or llms_txt / openapi when present), (4) ask the user for the credential named in auth_hint.

MCP server

The catalog is also an MCP server with four tools: search_apis (filters: query, category, mcp (official/remote/any), no_auth, free_tier, no_card, auth), get_api, get_reviews (user reviews with pros and cons) and list_categories. No key needed. Add it to your MCP client:

{
  "mcpServers": {
    "ai-agents-api-library": {
      "command": "npx",
      "args": ["-y", "ai-agents-api-library"]
    }
  }
}

Claude Code: claude mcp add ai-agents-api-library -- npx -y ai-agents-api-library

No install: remote endpoint (Streamable HTTP, no key) https://ai-agents-api-library.vercel.app/mcp, e.g. claude mcp add --transport http ai-agents-api-library https://ai-agents-api-library.vercel.app/mcp. Listed in the official MCP Registry as io.github.eater2/ai-agents-api-library.

Claude skill and plugin

The skill tells Claude when to reach for the catalog and how to pick a service. The plugin bundles the skill with the MCP server:

• Claude Code plugin (skill + MCP server):
  Code

  Copy

  /plugin marketplace add eater2/ai_agents_api_library
  /plugin install ai-agents-api-library@eater2
  

• Skill only, Claude Code: copy skills/ai-agents-api-library/ to ~/.claude/skills/ (all projects) or .claude/skills/ (one project).
• Skill only, claude.ai / Claude Desktop: download the skill zip and upload it under Settings → Capabilities → Skills.

Inclusion criteria

• The service exposes a public, self-serve programmatic interface (REST, GraphQL, SDK) or an MCP server.
• A human needs to act at most once — sign up and create a key or approve OAuth. After that the agent works unattended.
• The interface is documented and currently active (links last checked on the date shown in the infobox).
• Consumer-only apps, waitlists, sales-gated enterprise products, agent frameworks and IDEs are excluded — they are agents or tools for building agents, not services an agent calls.

Legend

• MCP ✅ — official MCP server maintained by the vendor
• MCP ◐ — community-maintained MCP server
• MCP — — no MCP server known; use the REST API
• 🆓 — free tier or free usage without payment
• ★ (date) — proof under the service name: SourceForge rating and review count, GitHub stars, Smithery uses — linked, with the date fetched

Web search

Search engines and answer APIs that return fresh web results, snippets or full page content in agent-friendly formats. — 14 services. JSON: catalog/web-search.json

Web scraping and browser automation

Crawl, scrape and convert pages to Markdown/JSON, or drive a remote headless browser (clicks, forms, logins). — 18 services. JSON: catalog/web-scraping-browser.json

Knowledge and research data

Encyclopedias, academic papers, news, computational knowledge and up-to-date library documentation. — 16 services. JSON: catalog/knowledge-research.json

Image generation and editing

Text-to-image, image editing, inpainting, upscaling and background removal. — 10 services. JSON: catalog/image-generation.json

Video generation and editing

Text/image-to-video models, talking avatars, programmatic video rendering and video hosting. — 14 services. JSON: catalog/video-generation.json

Speech and audio

Text-to-speech, speech-to-text, voice cloning, dubbing and audio intelligence. — 13 services. JSON: catalog/audio-speech.json

Music generation

Generate songs, instrumentals, loops and sound effects from prompts. — 6 services. JSON: catalog/music-generation.json

3D generation and assets

Text/image-to-3D mesh generation, texturing and 3D asset libraries. — 6 services. JSON: catalog/3d-generation.json

Architecture, CAD and BIM

Building information models, CAD geometry, construction management and GIS platforms with programmatic access. — 8 services. JSON: catalog/architecture-cad-bim.json

Diagrams and software architecture

Render or edit diagrams (Mermaid, PlantUML, C4), whiteboards and architecture models. — 8 services. JSON: catalog/diagrams-software-architecture.json

Design and UI

Read and write design files, generate branded graphics and publish websites. — 6 services. JSON: catalog/design-ui.json

Documents, OCR and presentations

Parse PDFs and scans, convert file formats, generate slides and collect e-signatures. — 14 services. JSON: catalog/presentations-documents.json

Translation and language

Machine translation, grammar and style checking. — 6 services. JSON: catalog/translation-language.json

Code execution sandboxes

Isolated cloud environments where an agent can run code, shells and whole dev environments safely. — 10 services. JSON: catalog/code-execution-sandbox.json

Developer platforms and DevOps

Source control, CI/CD, monitoring, error tracking, incident management and package registries. — 12 services. JSON: catalog/developer-devops.json

Cloud and hosting

Cloud providers, serverless and edge platforms, and site hosting an agent can deploy to and manage. — 10 services. JSON: catalog/cloud-hosting.json

Databases

Managed SQL, NoSQL, key-value and analytics databases an agent can create, query and manage. — 12 services. JSON: catalog/databases.json

Vector search, memory and RAG

Vector databases, retrieval (RAG) services and long-term memory layers for agents. — 9 services. JSON: catalog/databases-vector-memory.json

Email, team chat and notifications

Send and receive email, post to team chat (Slack, Discord), send push notifications; manage meetings. — 10 services. JSON: catalog/communication-email-chat.json

SMS and messaging apps

Send and receive SMS and messages on WhatsApp, LINE or Telegram through a messaging provider's API. — 10 services. JSON: catalog/sms-messaging.json

Voice agents and telephony

Place and receive phone calls handled by AI voice agents, real-time audio/video rooms. — 9 services. JSON: catalog/voice-agents-telephony.json

Productivity and workspace

Email, calendars, files, notes, tasks and project management. — 17 services. JSON: catalog/productivity-workspace.json

CRM, support and marketing

Contacts, deals, support tickets and email campaigns. — 8 services. JSON: catalog/crm-support-marketing.json

Social media

Read and publish posts, comments and videos on social platforms. — 10 services. JSON: catalog/social-media.json

Maps, geolocation and weather

Geocoding, routing, places, map tiles and weather forecasts. — 18 services. JSON: catalog/maps-geo-weather.json

Finance, payments and market data

Accept payments, move money, access bank data and query stock, FX and crypto prices. — 16 services. JSON: catalog/finance-payments.json

E-commerce

Manage stores, products, orders and marketplace listings. — 8 services. JSON: catalog/ecommerce.json

Automation and integration platforms

One connection that exposes thousands of third-party app actions to an agent, with managed auth. — 15 services. JSON: catalog/automation-integration.json

Model APIs and inference

LLM, embedding and multimodal model endpoints an agent can delegate sub-tasks to. — 18 services. JSON: catalog/model-inference.json

Related directories and registries

Other machine-readable sources agents can use to discover tools:

• Official MCP Registry — The official Model Context Protocol registry; agents can call its REST API (with OpenAPI spec) to search and list available MCP servers. — machine-readable: https://registry.modelcontextprotocol.io/v0/servers
• public-apis/public-apis — A community-curated GitHub list of 1,400+ free public APIs by category, fetchable as raw Markdown for programmatic parsing. — machine-readable: https://raw.githubusercontent.com/public-apis/public-apis/master/README.md
• APIs.guru OpenAPI Directory — An open, unauthenticated directory of 2,500+ public OpenAPI specs; agents fetch list.json to discover APIs and their OpenAPI definitions. — machine-readable: https://api.apis.guru/v2/list.json
• punkpeye/awesome-mcp-servers — A widely-starred curated GitHub list of MCP servers by category, fetchable as raw Markdown for automated discovery. — machine-readable: https://raw.githubusercontent.com/punkpeye/awesome-mcp-servers/main/README.md
• Smithery — An MCP server registry and hosting gateway (6,000+ servers) whose REST API lets agents search servers and obtain connection URLs. — machine-readable: https://api.smithery.ai/servers
• Glama MCP Directory — A large scanned and scored registry of 90,000+ open-source MCP servers, queryable via a bearer-authenticated REST API. — machine-readable: https://glama.ai/api/mcp/v1/servers
• mcp.so — A community MCP server marketplace and browsable directory site, but it has no publicly documented JSON/REST API for programmatic access.
• PulseMCP — A directory of 21,800+ MCP servers updated daily; its Sub-Registry REST API (API key required) lets agents list and search servers. — machine-readable: https://api.pulsemcp.com/v0.1/servers
• llms.txt convention / directory — An open convention for a root-level llms.txt file giving agents a concise Markdown map of a site's key content; a community directory indexes published files, though it exposes no JSON API. — machine-readable: https://directory.llmstxt.cloud
• Postman API Network — The largest network of public API collections shared on Postman, browsable on the web but with no documented public API for programmatic discovery.
• RapidAPI Hub (Nokia API Hub) — A large third-party API marketplace with growing MCP support for agents, but with no public, unauthenticated catalog endpoint for bulk discovery.

Contributing

Edit only the files in data/ (usually data/catalog.json), run python scripts/build.py to regenerate the English, Polish and LLM files, and open a pull request. Every new entry must link to the vendor's official API documentation. Step-by-step guide: CONTRIBUTING.md.

See also

• Model Context Protocol
• Official MCP Registry
• llms.txt proposal

References

The initial candidate list was compiled from:

1. GetStream — AI Agent Tools Catalog
2. StackOne — AI Agent Tools Landscape 2026
3. Mastra — Best AI agent search tools
4. abitwise — AI-tools
5. Sylus — Top-rated connectors for AI tool integrations

_{Generated from data/catalog.json on 2026-09-25.}