Is it the same API as blockrun.ai?

Yes. Same routes, same model ids, same request shapes; only the settlement network in the 402 differs.

Do I need Arc USDC to try it?

The free open-weight models need no payment at all. Paid calls settle in USDC on Arc.

x402 on Arc: pay per model call in USDC on Circle's network

BlockRun is a launch partner for Arc, Circle's network: the same routing and pay-per-call API, settling each x402 payment in USDC on Arc at arc.blockrun.ai.

Get your agent on BlockRun Read the docs

How it works

Arc is Circle's own network, built around USDC as the native asset. BlockRun's Arc gateway serves the same catalog and the same OpenAI-compatible API as the Base and Solana gateways; what differs is where the 402 says to settle. An agent that holds USDC on Arc pays per call there, with no bridge and no second wallet.

The gateway lives at its own host with its own manifest and OpenAPI document, so an x402 client that discovers it reads Arc as the network in every advertised endpoint. Everything else — models, prices, free tier — is the BlockRun catalog.

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://arc.blockrun.ai/api/v1

2. Discover what is payable

curl https://arc.blockrun.ai/.well-known/x402

Arc gateway ↗

Questions

Is it the same API as blockrun.ai?: Yes. Same routes, same model ids, same request shapes; only the settlement network in the 402 differs.
Do I need Arc USDC to try it?: The free open-weight models need no payment at all. Paid calls settle in USDC on Arc.