Arabic Pipeline MCP Server

Arabic Pipeline API

Pay-per-call utilities for Arabic text, audio and documents, sold over x402 in USDC on Base.

No API key. No account. No subscription. The first request returns 402 Payment Required; the client signs a payment and retries; the money lands in the provider's wallet. That is the whole protocol — and it is why this service can pay a provider directly, with no payment processor in between.

url https://payapi.market/mcp

Live endpoints

The MCP server exposes the same four capabilities as tools, each behind its own x402 payment (text_metrics, text_normalize, audio_transcribe, doc_extract).

Endpoints

POST /text/normalize accepts a mode:

• light — lossless: whitespace, digit unification, bidi cleanup only.
• search — light + tashkeel removal + letter folding (أإآ→ا, ى→ي, ة→ه).
• index — search + punctuation stripped (use as a dedup / index key).

Try it

# 1. Any paid route answers 402 with a payment challenge
curl -i https://arabic-pipeline.arabic-pipeline.workers.dev/text/normalize \
  -H 'content-type: application/json' \
  -d '{"text":"مُحَمَّدٌ عَلِيّ","mode":"search"}'

# 2. Free routes (no payment needed)
curl https://arabic-pipeline.arabic-pipeline.workers.dev/openapi.json
curl https://arabic-pipeline.arabic-pipeline.workers.dev/

How x402 payment works (for agents)

1. Call the route with no payment header → 402 Payment Required.
2. The response carries a base64 PAYMENT-REQUIRED header and, in the body, accepts[] entries describing how to pay (network, asset, price, payTo).
3. Pick one entry, sign a payment for it, and retry the request with the PAYMENT-SIGNATURE header (base64 payment payload).
4. The server verifies and settles the payment (via the facilitator) and returns the real result plus a PAYMENT-RESPONSE header with the receipt.

The full machine-readable contract — including per-operation x-payment-info — is at GET /openapi.json.

Settlement

• Network: Base mainnet (eip155:8453), asset USDC (0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913).
• Payments are verified and settled by a public x402 facilitator (https://x402.dexter.cash — no account, no fees). The facilitator only executes the buyer's signed payment; it never holds funds.
• Settlement destination: 0x05523af5bd166816D1418Ebf7D6371e1fFB1D2e6.

Model endpoints

/audio/transcribe uses gemini-3.5-transcribe; /doc/extract uses gemini-3.6-flash with a JSON response schema. Both model names are configurable (GEMINI_TRANSCRIBE_MODEL, GEMINI_VISION_MODEL). The two text endpoints are pure computation and cost nothing to serve.

Local development

npm install
cp .dev.vars.example .dev.vars   # then add GEMINI_API_KEY
npm run dev                       # wrangler dev
npm test                          # vitest
npm run typecheck

Deployment

See DEPLOY.md. The short version: npm run login → npm run secret → npm run deploy → register the listing.

Two Workers are deployed from this repo:

npm run deploy              # REST API  -> arabic-pipeline.arabic-pipeline.workers.dev
npx wrangler deploy -c wrangler.mcp.toml   # MCP server -> arabic-pipeline-mcp.arabic-pipeline.workers.dev

Licence

MIT.