Monetize your APIs
for AI Agents and Bots
A low-code middleware framework that lets developers charge AI agents micropayments in crypto to access protected routes. Drop it into Express or Next.js in under 2 minutes.
How it works
The x402 payment loop — from first request to verified access.
AI Agent / Bot
Crawling content or querying an endpoint
Your API + Centinel
Validates on-chain signatures & manages sessions
Built for production
Everything you need for machine-to-machine micropayments, out of the box.
Replay protection
In-memory signature deduplication and on-chain transaction age checks prevent double-spending. Each signature can only be used once.
Multi-chain, multi-token
Accepts USDC, SOL, and ETH across Solana and Base L2. Agents pay with whatever token they have — you get paid either way.
Flexible billing
Choose per_request for pay-as-you-go access or per_session for timed JWT tokens. Set different prices per route.
Rate limiting
Built-in per-IP rate limiter blocks signature spamming after 5 failed attempts, protecting your RPC nodes from abuse.
Zero config
The CLI auto-detects your framework, language, and directory structure. One command scaffolds everything you need.
Edge-ready
Next.js middleware runs at the edge with Web Crypto — no cold starts, no Node.js SDK dependencies. Works on Vercel out of the box.
Who is this for?
If bots are consuming your resources for free, Centinel lets you charge them.
Publishers & Bloggers
AI crawlers like GPTBot and ClaudeBot are training on your articles, recipes, and reporting. Centinel lets you charge them per-page instead of blocking them entirely with robots.txt.
API & SaaS Providers
Instead of requiring agents to sign up, enter a credit card, and commit to subscriptions, charge them fractions of a cent per call. No accounts. No onboarding friction.
AI Compute Hosts
Running GPU models or fine-tuned nets? Charge executing agents exactly what the inference costs. Per-request pricing that matches your actual compute spend.