Call any frontier model through one endpoint
One OpenAI- and Anthropic-compatible endpoint for every frontier model. Provider list price on tokens, no markup, no subscription, priced before the call runs.
What it does
Send the JSON an OpenAI chat-completions client already sends — model, messages, stream, tools — and pick any model on the rate card by changing the model string. Anthropic-shaped requests go to the Messages-compatible path, and OpenAI's Responses shape has its own endpoint, so an existing client keeps its wire format.
Streaming, tool calls, vision inputs and multi-turn history behave as they do upstream; the response carries the usage the request actually consumed. Every model routes through the same endpoint, so switching models is a one-line change rather than a second integration.
The call
One endpoint, priced in dollars before it runs and settled in USDC. No API key and no account — the request pays for itself.
POST /api/v1/chat/completions
Host: blockrun.aiWhat it costs
Why per call
No seat, no minimum, no contract per vendor. Each request is quoted in dollars before it runs and settles on-chain, so an agent can pay for its own work without a human holding a credit card. How the payment works →
Related tools
Questions
Do I need an API key?
No. Payment is the authentication — a request carries an x402 payment header and settles in USDC on Base or Solana.
Is it OpenAI-compatible?
Yes. Point an existing OpenAI or Anthropic SDK at the base URL and the first call works, with no migration.
What does a call cost?
The provider's published token rate with no markup, plus a flat per-call fee. Every request is quoted in dollars before it runs.
Can I try it without paying?
Yes. Several models are free and need no wallet at all.