"Create React App" matching MCP connectors:

Free platform to test MCP clients without installing anything. Create mock tools with dynamic templates, configurable delays, conditions (if/then), and response sequences. Supports JSON-RPC 2.0 over Streamable HTTP. Built-in text_echo and json_echo tools. Rate-limited tiers: anonymous (5 calls/min, 1 mock tool), registered (10 calls/min, 4 mock tools), premium (60 calls/min, unlimited). Zero setup — no install, no registration required. More info: https://www.testmcp.dev

Signed, offline-verifiable contract-change authorization. Only a granted change can proceed.

Test curl retries locally or inspect remote 429/503 Retry-After traces; optionally share findings.

API Blueprint group count, body discarded

pipeheroA

io.github.pipehero

Debug webhooks from your AI agent: inspect and replay captured webhooks on localhost.

Cloudflare Workers MCP server: api-contract-validator

Cloudflare Workers MCP server: interactive-api-playground

Cloudflare Workers MCP server: api-schema-drift-detector

Cloudflare Workers MCP server: api-payload-auditor

Cloudflare Workers MCP server: api-mock-server

Cloudflare Workers MCP server: api-diff-monitor

dilli-email-validation-api-serverB

com.dillilabs.deva

An MCP server that provides tools to validate an email address using Dilli Email Validation API.

Public benchmark where agents submit Q&A answers and get scored on a leaderboard.

Search millions of x402 APIs for data, finance, validation, security, inventory, sync and automation

Instant no-signup webhook & HTTP-request inspector for testing webhooks and agent tool-callbacks.

API and website monitoring that validates the JSON a response returns, not just its status code. Create endpoint checks, pull incident reports carrying the actual failed payload, and read health scores from your editor.

Simceptor is an AI-native Mock API simulation platform with a built-in MCP server. It enables AI agents to create, inspect, update, and test dynamic mock APIs, conditional response rules, stateful session simulations, and network latency directly from context.

HttpStatus MCP Server — 24 AI-callable tools for API testing, mocking, monitoring, and security. Create and manage API mocks, run chaos engineering rules, validate OpenAPI specs, scan URLs for security issues, check SSL certificates, debug CORS, analyze redirect chains, decode JWTs, inspect HAR files, trace distributed requests, capture webhooks, build automation workflows (including Postman import), and set up uptime monitors — all from your AI assistant.

Send every row of a dataset, file or Google Sheet to any REST API as its own templated request.

API monitoring from your editor. Checks the JSON your endpoints return, not just the status code.