"Sort servers by usage in the last 30 days" matching MCP connectors:

Conformance checker for MCP servers. Free, no key, verdicts recomputable and re-measured daily.

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

Check that your AI is being logical. Free tool that mathematically catches contradictions in agent reasoning. No account needed. Also offers paid guardrails that converts natural language to formal verification proofs, that anyone can check succinctly.

A fully free linter for agent skill files: lint_skill validates YAML frontmatter, structure, size budgets, and safety phrasing with a pass/fail verdict; packaging_check validates zip layout against marketplace rules; plus regex_test, json_validate, diff_texts, and cron_explain for skill authors. No license or account required.

Verify scraped data against the live source page. Signed verdicts, $0.01 via x402.

MCP tool observatory: do registry servers answer, and are their answers true? No key.

Give AI coding agents access to your Vynix visual feedback, bug reports, and AI diagnosis.

Accessibility pre-checks (WCAG/BFSG) in a real browser + statement drafts. Pay per call.

Voice-powered bug reporting with 13 MCP tools. Record bugs by talking; let AI find and fix them.

Continuous website testing by Validoria — monitor security, SEO, performance, and accessibility.

Find MCP servers and check whether they actually respond, via live handshake probes.

Grade MCP servers A to F with the open behavioral litmus. npm: full toolset; hosted: lookups only.

Check if your MCP server is ready to publish on the MCP Registry, Smithery, or npm.

Runs your code against a contract; returns HELD or BROKE at the exact input. Deterministic.

One-cent x402 and MCP readiness checks plus fixed-price marketplace launch packs.

Read-only MCP server for the OPERANT AI operating-agent calibration benchmark.

Test the voice agents you run: scored transcripts, pass/fail verdicts, latency and WER metrics.

MCP server for the Fail Modes taxonomy — a knowledge base of AI system failure modes

PQS scores any prompt before the model runs. 8 dimensions. 5 frameworks. Pre-flight, not post-hoc.

The world's first named AI prompt quality score. Score, optimize, and compare LLM prompts before they hit any model. Free tier available. Built on PEEM, RAGAS, G-Eval, and MT-Bench frameworks. x402-native on Base.