metered-api-marketplace

# Metered API Marketplace Provide a production-lean template for: **OpenClaw Skill → Public API Endpoint → Usage Metering → Crypto Payment Gateway → BTC/ETH wallets**. This skill ships a runnable reference server (Fastify + SQLite) that: - Accepts **structured JSON input** - Performs a **high-value transformation** (pluggable “transformers”) - Returns **structured JSON output** - Enforces **signed API key** auth - Checks **prepaid balance**, deducts per call, and logs usage - Accepts **payment webhooks** (Coinbase Commerce / BTCPay Server style) - Applies a **2.5% platform fee** in the ledger (fee addresses configurable) ## Workflow (do this in order) ### 1) Pick the productized capability (the thing people pay for) Choose ONE transformer that is: - high leverage (makes/keeps money) - repeatable (called often) - defensible (data, heuristics, workflow, or automation — not “generic summarization”) Good defaults: - revenue/offer optimizer - ad copy optimizer - lead scoring - contract risk flags If unclear, start with the included `revenue-amplifier` transformer and replace it later. ### 2) Run the reference server locally Use the bundled server in `scripts/server/`. Typical run: - `cd scripts/server` - `npm install` - `cp .env.example .env` and edit - `npm run dev` Set flat launch pricing in `.env`: - `COST_CENTS_PER_CALL=25` # $0.25/call ### 3) Create an API key Use `scripts/server/admin/create_key_pg.js` (or the admin HTTP endpoint) to create a key and starting balance. ### 4) Integrate from an OpenClaw skill / agent Call the public endpoint with: - `x-api-key` - `x-timestamp` (unix ms) - `x-signature` = `hex(HMAC_SHA256(api_secret, `${timestamp}.${rawBody}`))` ### 5) Add real payments Wire a payment processor webhook to `/v1/payments/webhook/:provider`. Providers are adapter-based: - start with “manual” credits (admin script) - then add Coinbase Commerce or BTCPay Server ### 6) Ship Deploy behind TLS (Cloudflare / Fly.io / Render / AWS / GCP). Put rate limiting at the edge + in-app. ## Bundled resources ### scripts/server/ Runnable reference implementation: - Fastify API server (long-running) - Postgres ledger (balances, usage, credits) - Signed API key auth - Rate limiting + basic anti-abuse - Webhook endpoint(s) ### scripts/nextjs-starter/ Vercel-ready Next.js API implementation: - Serverless API routes (no `listen()`) - Postgres ledger (Supabase Transaction Pooler recommended) - Same auth + pricing + webhook concepts ### references/ Read only when needed: - `references/api_reference.md` – endpoint contracts + auth/signing - `references/billing_ledger.md` – pricing, fee logic, idempotency - `references/providers.md` – provider adapters (Coinbase/BTCPay patterns)