_done

# _done > Actions for AI. Real-world tasks your agent can't do alone. > via x402/USDC on Base mainnet. No accounts, no API keys, no subscriptions. API cost starts from $0.01 per request. To call one: POST JSON to the endpoint, receive HTTP 402 with payment details, sign a USDC authorization, retry with the X-PAYMENT header, get the result. Supports Base and Solana USDC. Every API lives at its own subdomain: https://{api-name}.underscoredone.com Machine-readable discovery: /.well-known/x402.json (all payment-gated endpoints) and /openapi.json (aggregated OpenAPI 3.1 spec). ## APIs - [ASN Lookup](https://underscoredone.com/asn_lookup/): Look up the network operator, country, and address block behind any IP address or ASN number. [OpenAPI](https://asn-lookup.underscoredone.com/openapi.json) - [BIMI Checker](https://underscoredone.com/bimi_checker/): Checks whether a website's email branding setup is correct so its logo shows up in inboxes. [OpenAPI](https://bimi-checker.underscoredone.com/openapi.json) - [CORS Header Checker](https://underscoredone.com/cors_header_checker/): Send a URL and origin, get back exactly which cross-origin permissions that server grants. [OpenAPI](https://cors-header-checker.underscoredone.com/openapi.json) - [US CPI Data & Inflation Report](https://underscoredone.com/cpi_report_us/): Returns the latest, a specific month's, or a historical range of official US inflation (CPI) figures from BLS . [OpenAPI](https://cpi-report-us.underscoredone.com/op […gekürzt]