Callmeter

First paid job: parse a receipt → structured JSON for ~$0.10 (prepaid credits or x402 USDC on Base). Try the public demo https://api.callmeter.dev/demo/receipt-to-json then pay on tools/call. tools/list is free.

CallMeter is an MCP / API gateway of useful machine work for AI agents — jobs like receipt → JSON, schema transform, schema breaking-change detect, structured extract, screenshots, PDF text, invoice parsing, and durable webhook ingress/replay.

Pay per successful call with prepaid credits or x402 USDC on Base (enabling property, not the product).

This repository is documentation and client config only. It does not contain proprietary kernel source.

Receipt → JSON (Campaign DOC-RECEIPT)

Turn till slips, POS printouts, and mobile-money confirmations into merchant / date / currency / total / line_items JSON your agent can book.

Fail-closed: empty/garbage input → null merchant, total 0, empty line_items (no invented money). Africa-tuned (NGN ₦/kobo, KES M-Pesa, GHS MoMo, ZAR VAT, OPay, PalmPay, Paystack, Verve POS).

Related MCP server: navi-x402-mcp

Schema breaking-change detect

Compare two OpenAPI or JSON Schema documents and report producer-compat breaking changes. Deterministic — no LLM.

Body: {before, after, mode?: auto|json-schema|openapi, include_nonbreaking?: true}
Out: {mode, breaking, breaking_count, nonbreaking_count, changes[], summary}

Quick start — MCP clients

Claude Desktop

Add a remote MCP server using Streamable HTTP. Example claude_desktop_config.json fragment:

{
  "mcpServers": {
    "callmeter": {
      "url": "https://api.callmeter.dev/mcp",
      "headers": {
        "x-api-key": "YOUR_API_KEY"
      }
    }
  }
}

Replace YOUR_API_KEY with your prepaid key. Leave the header out to explore tools/list (unauthenticated); paid tools/call will return 402 for x402 flow.

Cursor

In Cursor MCP settings, add a Streamable HTTP server:

{
  "mcpServers": {
    "callmeter": {
      "url": "https://api.callmeter.dev/mcp",
      "headers": {
        "x-api-key": "YOUR_API_KEY"
      }
    }
  }
}

Same URL works for any MCP client that supports Streamable HTTP (POST JSON-RPC to the MCP endpoint).

Smithery / Glama

• Config schema: config-schema.json (apiKey → x-api-key)

• Config / metadata: smithery.yaml, server-card.json

• Notes: SMITHERY.md

• Glama: glama.json

Auth & billing

• Human checkout: mint an API key and buy min $10 / 1000 credits via Paystack at https://api.callmeter.dev/signup

• initialize / tools/list → 200 without a key

• tools/call unpaid → 402

• Bad key → 401

Credit peg: 1 credit = $0.01, min top-up $10. See pricing.md.

MCP tools (canonical)

extract.structured_data · extract.webpage · transform.json_schema · detect.schema_breaking_changes · capture.screenshot · extract.pdf · parse.receipt · parse.invoice · relay.webhook · replay.webhook

Underscore aliases remain accepted on tools/call for one release.

Example curls

See examples/ for scripts. Placeholders only — never commit real keys.

tools/list (no key)

curl -sS -X POST https://api.callmeter.dev/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}'

Unpaid tools/call → 402 (x402)

curl -sS -i -X POST https://api.callmeter.dev/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"transform.json_schema","arguments":{"mode":"draft","sample":{"a":1}}}}'

Expect HTTP 402 with payment-required details when no prepaid key is sent.

Prepaid schema call

curl -sS -X POST https://api.callmeter.dev/mcp \
  -H 'content-type: application/json' \
  -H 'accept: application/json, text/event-stream' \
  -H 'x-api-key: YOUR_API_KEY' \
  -d '{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"transform.json_schema","arguments":{"mode":"draft","sample":{"a":1}}}}'

Docs in this repo

License

MIT