Authentication

Version 1 is open and read-only — no API key or token is required. Make GET requests directly against https://apis.io/api/v1.

Code
curl "https://apis.io/api/v1/search?q=sms"

This matches APIs.io's open-discovery mission: the catalog is public, and there is no endpoint that mutates it.

API-key-ready

The OpenAPI contract defines an ApiKeyAuth security scheme that is not enforced in v1. It is declared so metering or higher rate tiers can be introduced later without a breaking change — if and when keys are required, they'll be sent as a header and documented here.

CORS

The API is served same-origin with apis.io, and responses are browser-friendly, so you can call it directly from web apps and from the agent surfaces.