Callmeter

Near-term paid hop: draft or validate JSON Schema (transform.json_schema ≈ $0.02) via x402 USDC on Base. Unpaid tools/call → HTTP 402. tools/list is free. Receipt→JSON (parse.receipt ≈ $0.10) remains demo/depth — https://api.callmeter.dev/demo/receipt-to-json. Prepaid fiat (Paystack/Flutterwave) unavailable.

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 x402 USDC on Base (default). Existing prepaid balances still debit if present; new fiat top-ups closed.

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"
      }
    }
  }
}

Leave the header out to explore tools/list (unauthenticated); unpaid tools/call returns 402 for x402. Optional YOUR_API_KEY only if an existing ledger balance remains — no Paystack top-up.

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 fiat checkout / Paystack / Flutterwave: unavailable (FIAT_MIX_CLOSED)

• Signup: https://api.callmeter.dev/signup — mint key only; no card packs

• initialize / tools/list → 200 without a key

• tools/call unpaid → 402

• Bad key → 401

• Credit peg: 1 credit = $0.01 (ledger equivalence; not a buyable pack while fiat closed). 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.

Existing-balance 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