"QuickBooks - Accounting and Financial Software" matching MCP connectors:

Detect breaking changes, generate changelogs, diff, and validate OpenAPI specs.

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

Apideck Unified API MCP — 330 tools across 200+ SaaS connectors (accounting, CRM, HRIS, ATS).

Discover, pay for, execute, and publish APIs through Apiosk.

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

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

Deploy production REST APIs from JSON schemas in seconds. Manage projects, schemas, and deployments.

End-to-end API testing — generate and run tests from OpenAPI, curl, Postman, or real user traffic.

40+ developer tools from Context7, Code Runner, Python Execute, NPM Sentinel, PlantUML, and Microsoft Learn. Docs lookup, code execution, security scanning. Starts at $0.01/call. Get your API key at app.xpay.sh or xpay.tools

Swagger Petstore API (v1.0.27) as MCP for testing and prototyping powered by the HAPI MCP server

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

Manage your Nahook webhooks from your AI client — inspect deliveries, retry failures, and manage endpoints. Connects over OAuth, no API keys

Verify x402 endpoints and prepare agent-catalog listings before agents pay.

MCP server and REST API for querying OpenAPI specs. Endpoint-level extraction, schema resolution, 100+ APIs indexed.

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

Free *.pntr.dev dev subdomains — register subdomains, manage DNS and wildcard records, receive email on disposable inboxes, and capture HTTP requests for webhook debugging. OAuth sign-in; free tier.

Monitor MCP servers, API contracts and AI outputs for schema drift. Alerts on breaking changes.

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.

AI-callable tools for API mocking, testing, monitoring, security, and automation.