Doc Extract API MCP server

doc-extract-api

Document-to-structured-JSON extraction API. Takes a PDF/PNG/JPEG and returns clean JSON. Four fixed document types (invoice, receipt, contract, resume) get a matched schema plus domain-specific validation; /extract/custom accepts any JSON Schema, so a caller isn't limited to those four types. Built for autonomous AI agents: no signup, no API key, no human checkout — an agent discovers the price and pays per call via x402 v2 (USDC), entirely over HTTP, and can find this service programmatically via the x402 Bazaar discovery catalog. Also published as an MCP server (doc-extract-api-mcp on npm, and on the official MCP Registry) — but that's a client for the same paid API, not a free alternative: every MCP tool call is a real x402 payment from a wallet you supply, not a locally-run, unmetered extraction. There is no free path to this service.

Why x402, not Stripe

Stripe Checkout is built for humans — it collects a card through a UI, and its payment button actively resists non-trusted, programmatic (agent-driven) submission. x402 revives the HTTP 402 Payment Required status code: hit a paid endpoint with no payment, get back a 402 whose PAYMENT-REQUIRED header carries a complete, machine-readable manifest (price, network, receiving address, asset, and — via the Bazaar extension — a full input/output schema with a real example). Retry with an X-PAYMENT header carrying a signed USDC transfer authorization, and the request goes through. No account, no key, no human in the loop — the discovery step and the payment step are the same HTTP round trip.

Payment is only settled after the extraction succeeds — @x402/hono's middleware verifies the payment signature before running the handler, but only executes the actual on-chain transfer if the handler returns a non-error status (confirmed: this project's paymentMiddlewareFromConfig call skips settlement whenever the wrapped route responds ≥400). A failed extraction costs the caller nothing.

Discovery: the x402 Bazaar

The Bazaar (GET {facilitator}/discovery/resources) is a live, queryable catalog of x402 services — ~15k listings as of this writing, searchable by agent clients (client.extensions.bazaar.search({ query: "..." })). Getting listed isn't a submission form: a facilitator catalogs a resource automatically the first time it processes a real payment that echoes the route's declared bazaar extension. src/lib/discovery.ts declares that extension for all four routes — full input schema (multipart form-data, a file field) and a real, verified output example — so once a route's first live mainnet payment lands, it becomes findable in the catalog with enough detail for an agent to integrate correctly without reading any docs. As of this writing the /extract/invoice catalog entry is still showing a stale pre-migration record rather than this rich content — see git history / ask for status; /extract/receipt, /extract/contract, and /extract/resume haven't had a mainnet payment yet so aren't catalogued at all.

Positioning (from surveying the live Bazaar before writing the listing copy): generic OCR competitors are free but return raw unvalidated text; generic structured-extraction competitors charge ~$0.10/call and require the caller to already have plain text, not a raw file. This is the only listing found doing both — raw PDF/image in, a fixed validated schema out. Pricing (see wrangler.toml) is matched per-route to the lowest verified live-402 price from a direct competitor in that category, not set independently — $0.02 for invoice/receipt/resume/custom, $0.03 for contract (its real comparable is a cent higher). See src/lib/discovery.ts for the exact listing copy and each route's tags (serviceName/tags/description).

Architecture

Shortened. The full README is on GitHub.