Show HN: X402 Inspector (Find misconfigurations in your x402 API)

A developer tool called X402 Inspector launched on Hacker News to validate x402 payment challenges on paid API endpoints, checking the HTTP 402 response shape, USDC amount encoding, and Base, Base Sepolia, Solana, and Stellar address formats and flagging spec deviations in plain language. The tool is one of 11 free live utilities from the same site, which also includes an AI Agent Protocol Inspector that scans URLs for MCP, A2A, and ARD support, an ERC-8004 Inspector for on-chain agent identity and reputation, and an Agent Commerce Gate that combines ERC-8004 identity with x402 payment-challenge validation into an allow/warn/block decision. All tools are free, with a $5/month tier for PNG, SVG, and PDF exports and shared links.

Engineer your AI's context — visually. Is your site ready for AI agents? Scan any URL for MCP , A2A , and ARD support — live handshake, agent card, and catalog checks in seconds. Compare 20+ models → https://contextiq.trango-compute.com/dashboard/token-inspector 11 live tools · free · no sign-up on public tools Token Inspector Compare token counts and costs across GPT-4o, Claude, Gemini, and 20+ models. Know your monthly bill before you commit. AI Agent Protocol Inspector Enter any URL and detect MCP, A2A, and ARD support. Live MCP handshake with tools/list, agent card parsing, and ai-catalog.json discovery. RAG Chunk Inspector See exactly how any document splits into chunks. Compare tiktoken, sentence, and paragraph strategies with a live LLM context preview. Agent Workflow Visualizer Paste a GitHub URL — instantly see your agent graph. Supports LangGraph, CrewAI, AutoGen, Google ADK, and OpenAI Agents SDK. Agent Trace Inspector Paste an OTLP JSON trace from LangSmith, Langfuse, or OpenTelemetry and see the full agent graph — with per-node token attribution for LangGraph, CrewAI, and OpenAI Agents. Memory Architecture Visualizer Design agent memory layers as a DAG. Map episodic, semantic, and procedural memory with token budgets and data flows. HyDE Visualizer See why hypothetical document embeddings retrieve better. Compare all-MiniLM-L6-v2 cosine scores for direct query vs HyDE across your corpus chunks. OIDC Inspector Scan any domain for OpenID Connect configs. Detects Google, Microsoft, Auth0, Okta, and more across 11 subdomains. DNS Inspector See every DNS record for any domain — A, MX, NS, TXT, CAA — plus SPF/DMARC verdicts and DNS host / mail provider detection. x402 Inspector Paste a paid endpoint and validate its x402 payment challenge — HTTP 402 response shape, USDC amount encoding, and Base/Base Sepolia/Solana/Stellar address formats. Flags spec deviations in plain language before you ship. ERC-8004 Inspector Enter an agent ID and look up its on-chain identity and reputation — live reads from the ERC-8004 Identity and Reputation registries on Ethereum, Base, Arbitrum, Polygon, Avalanche, and BNB Chain. Beta. Agent Commerce Gate Combines ERC-8004 identity/reputation with x402 payment-challenge validation into a single allow/warn/block decision — check a counterparty before your agent pays it. Pro. Start building better AI systems. Free to use. $5/month to export. All tools free forever. Upgrade for PNG, SVG, PDF exports and shared links. No credit card required.