# LimitGuard

## Docs

- [API Reference](https://docs.limitguard.ai/api-reference/introduction.md): Complete reference for all 64 LimitGuard API endpoints
- [Authentication](https://docs.limitguard.ai/authentication.md): API keys, x402 USDC micropayments, and sandbox mode
- [February 20, 2026](https://docs.limitguard.ai/changelog/2026-02-20.md): Documentation site launch
- [Discovery](https://docs.limitguard.ai/discovery.md): Machine-readable discovery for AI agents — MCP, A2A, x402, and llms.txt
- [AI Agent Integration](https://docs.limitguard.ai/guides/ai-agent-integration.md): How AI agents discover and use LimitGuard — MCP, A2A, and x402
- [Error Handling](https://docs.limitguard.ai/guides/errors.md): Complete error catalog with causes and fixes
- [Rate Limits](https://docs.limitguard.ai/guides/rate-limits.md): Rate limit behavior, tiers, and Retry-After headers
- [Trust Architecture](https://docs.limitguard.ai/guides/trust-architecture.md): Zero-access model, data flow, and security architecture
- [Webhooks](https://docs.limitguard.ai/guides/webhooks.md): Real-time event notifications with HMAC signature verification
- [Introduction](https://docs.limitguard.ai/introduction.md): Trust Intelligence API for the Agent Economy
- [Pricing](https://docs.limitguard.ai/pricing.md): Pay only for what you use — USDC per API call
- [Quickstart](https://docs.limitguard.ai/quickstart.md): Get your first trust score in under 3 minutes
- [Sandbox Mode](https://docs.limitguard.ai/sandbox.md): Test the API for free — no wallet or API key required
- [x402 Protocol](https://docs.limitguard.ai/x402-protocol.md): Pay-per-use USDC micropayments for AI agents — no subscription required

## OpenAPI Specs

- [openapi](https://docs.limitguard.ai/api-reference/openapi.json)