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damien os
damien os

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Building SQLite x402 Gateway: Turn Any SQLite Database into a Pay-Per-Query API

#node #web3 #ai #opensource

Over the past few days, I've been exploring Coinbase's x402 protocol — a simple yet powerful standard for machine-to-machine micro-payments using HTTP 402 Payment Required.

The result is SQLite x402 Gateway, a lightweight open-source tool that lets you transform any existing SQLite database into a monetized API in minutes.

Why This Project?

Most developers already have SQLite databases—whether for personal tools, internal CRMs, product catalogs, research data, or side projects.

The idea was to make it trivial to expose this data via an API that can be paid for on a per-query basis, especially by autonomous AI agents.

No more building custom payment logic or manually creating API routes for every table.

Core Features

  • Automatic schema introspection

    • Scans your SQLite database and generates API routes automatically.

  • x402 protocol support

    • Full implementation (simulation + real testnet).

  • Simulation mode

    • Test everything locally with zero blockchain setup.

  • Real testnet mode

    • One-command setup for Base Sepolia with actual USDC test payments.

  • Admin dashboard

    • Track requests, revenue, popular routes, and toggle free mode.

  • Security-first

    • Only SELECT queries are allowed by default.

How It Works

1. Demo / Quick Start 

npm install
npm start
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A sample database with fake data is created automatically.

2. Monetize Your Existing Database 

node scripts/monetize.js /path/to/your/database.db
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The script:

  • analyzes your tables,
  • suggests pricing based on data volume,
  • updates the configuration automatically.

3. Enable Real Payments

Generate a wallet, switch to real-testnet mode, and you're ready to receive micro-payments.

Technical Stack

  • Node.js
  • Express
  • Native node:sqlite
  • x402 protocol (simulation + real adapter)
  • Simple HTML/JavaScript admin interface

The project is intentionally lightweight (around 70 dependencies in simulation mode) compared to full blockchain SDKs.

Current Limitations (Transparency First)

  • Only SELECT queries are supported for security reasons.
  • Simulation mode is ideal for development but is not a replacement for blockchain verification.
  • Mainnet deployments require a proper x402 facilitator and production configuration.

Future Ideas

I'm considering adding:

  • Pagination with dynamic pricing
  • Query parameter whitelisting
  • Rate limiting per wallet address
  • Improved analytics
  • Authentication plugins
  • Cached paid queries
  • OpenAPI/Swagger generation

GitHub Repository

👉 https://github.com/damienos61/SQLite-x402-Gateway

If you find the project interesting, feel free to leave a ⭐.

I'd Love Your Feedback

What do you think about this approach?

  • Would you use something like this in your own projects?
  • What use cases do you see for pay-per-query SQLite APIs?
  • Any security or architecture suggestions?
  • What feature would you add first?

Contributions are welcome—the project is released under the MIT License.

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