# CheapAIAPI for coding agents

CheapAIAPI is a prepaid HTTP generation API. There is no public SDK, CLI, OAuth flow, or anonymous sandbox. Integrate the documented HTTP contract with a bearer API key.

## Start here

- [Agent index](https://cheapaiapi.org/llms.txt)
- [Agent instructions](https://cheapaiapi.org/agents.md)
- [OpenAPI specification](https://cheapaiapi.org/openapi.json)
- [Starting prices as JSON](https://cheapaiapi.org/pricing.json)
- [Starting prices in Markdown](https://cheapaiapi.org/pricing.md)
- [API documentation](https://cheapaiapi.org/docs)
- [Request an API key](https://cheapaiapi.org/contact)

## Authentication

Send `Authorization: Bearer sk_cheap_...`. Do not invent, log, commit, or expose a key. Do not make a live request until the user supplies `CHEAPAIAPI_KEY` and explicitly asks for one.

Unauthenticated `/v1/*` requests return HTTP 402 with an `access` object and `Link` headers pointing at starting prices and contact. Invalid or revoked keys return HTTP 401. The 402 response is not a cryptocurrency payment quote and does not include on-chain payment headers.

## Billing

CheapAIAPI uses a prepaid API balance. Public starting prices are available without a quote. Lower account-specific volume pricing and account access start at contact.