x402 on Base: the original BlockRun gateway
blockrun.ai settles each x402 payment in USDC on Base: one OpenAI-compatible endpoint for every model, media generation, search and RPC, priced per call, no API keys.
How it works
Base is where BlockRun launched and where the widest set of clients pay by default: the MCP server, the Python, TypeScript and Go SDKs, ClawRouter and the framework plugins all create a Base wallet on first run. A card onramp funds it in one step, so a developer with no USDC can be paying per call within minutes.
The Base gateway's manifest, OpenAPI document and llms.txt are the reference copies of the discovery surface; the Solana and Arc gateways publish the same shape with their own network. Every paid call settles on-chain and is verifiable without trusting BlockRun.
Behind it is the BlockRun catalog: 78 chat models plus image, video, music and speech generation, search, market data and multi-chain RPC, priced per call. 6 open-weight models are free and need no wallet.
Setup
1. Base URL
https://blockrun.ai/api/v12. Discover what is payable
curl https://blockrun.ai/.well-known/x402Questions
- How do I get USDC on Base?
- Send it from an exchange to your wallet on Base, bridge it, or use the one-time card onramp the MCP and SDKs expose.
- Is there a free tier?
- Yes — the open-weight models are free and need no wallet.