x402-data-api

Grey Ridge Signals — Agent-Native x402 Data & Security APIs

Pay-per-call crypto, DeFi, prediction-market, and on-chain data for AI agents — plus MCP security scanning — over the x402 payment protocol on Base mainnet.

No account, no API key, no subscription. An agent pays inline in USDC (from $0.001/call) and gets the data back in the same request. Every data endpoint has a free preview so an agent can taste the payload before paying.

• Base URL: https://x402-data-api.sigrunner.workers.dev

• MCP endpoint (streamable-http): https://x402-data-api.sigrunner.workers.dev/mcp

• Canonical domain: https://x402-data-api.sigrunner.workers.dev (same API)

• Discovery: /.well-known/x402 · /openapi.json · /llms.txt

• Network: Base mainnet (eip155:8453), USDC. Settles via the non-custodial xpay facilitator — no Coinbase/CDP account needed. Also listed on the CDP x402 Bazaar.

Two flagships — what agents actually pay for

1. MCP server security scan (/scan/mcp, $0.05) — a prompt-injection / tool-poisoning audit of an MCP server's tools (OWASP LLM01/LLM08). Zero-egress: for private/OAuth-gated servers you POST only the tools/list JSON — nothing else leaves your side. There is no free equivalent for this (unlike token-safety, where free multi-chain scanners exist). Free preview: POST /scan/mcp/preview. CI gate: uses: rezearcher/x402-data-api/actions/mcp-scan@main.

2. Pre-trade decision gate (/gate/swap, $0.008 · /chain/token-report, $0.01) — a decision (GO/HOLD/BLOCK, SAFE/CAUTION/AVOID) sized to your trade, not raw flags your agent has to interpret. Base-native; if you trade other chains, keep your multi-chain scanner and use this on Base.

Everything below is the full catalog (crypto/DeFi data, on-chain reads, LLM, enrichment). Measured reliability at /status (not an SLA).

Endpoints

Crypto & DeFi data

Base on-chain (JSON-RPC read primitives)

Base-native, multi-provider RPC with automatic failover (never fails a paid call on one provider's rate limit).

Agent trading gates (new)

Security

Free previews: GET /crypto/prices/preview, /crypto/funding/preview, /defi/yields/preview, /chain/block-number/preview, /chain/gas-price/preview (full live data, not truncated), /scan/mcp/preview?url=. Zero-egress MCP scan (for private/OAuth-gated servers): POST /scan/mcp/preview with {"tools":[…]} is the free counts-only preview; POST /scan/mcp with the same body is the paid itemized scan — nothing leaves your side. One-liner: examples/mcp-scan-preview.sh.

MCP server (the pull channel)

Add one remote MCP server and your agent gets the whole toolset. initialize and tools/list are free so agents can discover the tools; paid tools/call returns an x402 challenge.

tools/list advertises 22 tools: crypto_prices, crypto_funding, defi_yields, pm_markets, chain_block_number, chain_gas_price, chain_balance, chain_token_balance, chain_tx, chain_wallet, chain_token_security (paid Base RPC + data, EIP-7702 delegated-EOA aware), crypto_prices_preview, crypto_funding_preview, defi_yields_preview, pm_markets_preview, chain_block_number_preview, chain_gas_price_preview, chain_token_security_preview (free), and scan_mcp_server, scan_mcp_preview, enrich_tech_risk, enrich_domain (security).

// add to your MCP client config
{
  "mcpServers": {
    "grey-ridge-x402": {
      "type": "streamable-http",
      "url": "https://x402-data-api.sigrunner.workers.dev/mcp"
    }
  }
}

MCP client (mcp-client/ — the stdio companion)

For stdio-only MCP clients (Claude Desktop, Cursor, CLI agents), the repo ships a companion package, x402-data-api-mcp, in mcp-client/. It runs on the agent's own machine, speaks MCP over stdio, and proxies to the same Worker /mcp endpoint — it adds no data surface, just a transport + x402 payment shim so stdio-only clients can reach the same tools (22 tools, including paid ones when a wallet key is configured).

Install / run (local path). The package is not yet published to npm, so run it from the repo:

cd mcp-client
npm install
npm run build          # tsc → dist/server.js
node dist/server.js    # start (or: npm start)

Intended path (once published): npx x402-data-api-mcp (the package's bin target is dist/server.js, so npx runs the same server).

Configuration. Copy mcp-client/.env.example to .env in mcp-client/: WORKER_BASE_URL defaults to the deployed Worker (set it only to point at your own mirror), and X402_WALLET_PRIVATE_KEY is optional — set it to auto-settle paid tools (HTTP 402) via x402; leave it empty to run only the free/preview tools. The client reads both straight from process.env at startup.

// stdio client config (local path)
{
  "mcpServers": {
    "grey-ridge-x402-local": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-client/dist/server.js"]
    }
  }
}

Call it (HTTP)

BASE=https://x402-data-api.sigrunner.workers.dev

# free preview — real sample, no payment
curl -s "$BASE/crypto/funding/preview"

# paid — returns HTTP 402 with an x402 payment-required challenge until you attach payment
curl -i "$BASE/crypto/funding?limit=10"

Any x402-capable client (e.g. the x402 libraries) handles the 402 → sign → retry automatically.

Measured status

Uptime and latency per safety route are measured from a probe cron and published in docs/STATUS.md (regenerated hourly; window stated in the file, not an SLA).

How it runs

A single Cloudflare Worker implements every HTTP endpoint and the MCP server behind a method-aware x402 gate. All upstreams are free/keyless public APIs (DefiLlama, Hyperliquid, OKX, Polymarket Gamma, Base JSON-RPC, NVD/EPSS/CISA-KEV, crt.sh/RDAP/DoH); every address/hash/domain input is validated and SSRF-guarded (fixed upstream hosts, no user-supplied targets except the explicitly-scoped /scan/mcp and enrichment endpoints).

License

MIT — see LICENSE.

Agent-framework examples

Pre-trade token guard (/gate/swap, $0.008 USDC via x402 on Base). Free sample: curl "https://x402-data-api.sigrunner.workers.dev/gate/swap/preview?token=degen"

• Node: docs/examples/swap-gate/gate.mjs

• LangChain.js tool: docs/examples/langchain/swapGuardTool.mjs

• ElizaOS action: docs/examples/elizaos/swapGuardAction.mjs