API Development MCP Servers for HTTP / API

JSONPlaceholder MCP — wraps JSONPlaceholder fake REST API (free, no auth)

One MCP endpoint over 69 public PPN APIs: search_apis to discover, execute_api to call. Free tier.

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Send and receive webhooks, manage customer endpoints, and inspect and retry deliveries.

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Any API, four tools: discover, call with routing and signed receipts, verify, dispute.

Sanctions API docs and request validation, with account-linked synthetic sandbox testing.

AI-native mock API server with MCP. Create REST/SOAP mocks from Claude, Cursor, or Windsurf.

MCP server for AI access to Swagger by SmartBear.

Unified.to MCP server — one API for 500+ B2B SaaS integrations across 28+ categories

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Receive, inspect, replay and deliver webhooks — with signature verification and agent triggers.

Fire-and-forget webhooks for agents with guaranteed, retried delivery and status polling. x402

Keyless webhook endpoints: capture, wait, replay, forward, and generate types from real traffic.

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Discover and call 10,000+ production APIs from one MCP server. Pay-per-call billing for AI agents.

Try 26 utility REST APIs keylessly: NAICS classification, IP geo, email validation, currency.

Discover, rate and compare APIs and providers in the APIs.io catalog; manage a listing you own.