1
Get an API Key
Create a free API key with a single request — no account or credit card needed.
Response
2
Try Sandbox Mode (Free)
Test the API without using real data sources or quota by adding the sandbox header:Sandbox returns deterministic mock data — same input always gives the same output. No real data sources are called and no quota is consumed.
3
Make a Live Entity Check
Remove the sandbox header for real results against 8 data sources:
Response
4
Try a Quick Risk Score
For fast risk-only assessment (2 sources, cheaper):
Response Quality Tiers
Control cost vs. freshness with theX-Response-Quality header:
Next Steps
Authentication
API keys, x402 USDC payments, and sandbox mode
Pricing
Full pricing table for all endpoints and tiers
Error Handling
Complete error catalog with causes and fixes
AI Agent Integration
How AI agents discover and use LimitGuard