---
name: metered-api-marketplace-452518a10431
description: Build and operate a metered public API endpoint ("agent microservice") for OpenClaw skills/agents with API-key auth, per-request usage logging + pricing, prepaid balances, and crypto top-ups (BTC/ETH) via payment-processor webhooks. Use when you want to monetize a capability as a public API, add rate limiting/anti-abuse, implement a credit ledger, or add revenue share / platform fee logic.
---

# 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)


---
Source attribution: modbender
Original project: https://github.com/modbender/skill-library-mcp/blob/d9c8fe903b5b4e82237dbe8d0df8567783022e18/data/metered-api-marketplace/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2025 skill-library-mcp contributors

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: modbender
Original project: https://github.com/modbender/skill-library-mcp/blob/d9c8fe903b5b4e82237dbe8d0df8567783022e18/data/metered-api-marketplace/SKILL.md
Attribution basis: Source repository record

Fields of work: Development & Engineering, Marketing
Roles: Backend Developer, Data Engineer, DevOps / SRE, Growth Marketer, Product Marketer
Specialties: API, Backend
Tools: Btcpay Server, Coinbase Commerce, Fastify, Sqlite
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 4e9114b04d9142332b0aa9088b981151a2779a7537104e778639145c8b6da49a