HostDeFi › RPC › Arbitrum One

Arbitrum One RPC endpoint

JSON-RPC over HTTPS POST (chain id 42161). The first 50 calls per IP are free — after that, either a flat $25 key (rk1_*, paid once in USDC on Solana or Base, 3,000 calls/min + batch 100) or the machine-payable x402 lane at $0.002/call, where agents pay per request in USDC with no key or signup at all.

Endpoint

https://hostdefi.com/api/rpc/arbitrum

Try it

curl -s -X POST https://hostdefi.com/api/rpc/arbitrum -H 'content-type: application/json' -d '{"jsonrpc":"2.0","id":1,"method":"eth_chainId","params":[]}'

Paid lanes

x402, per-call — POST https://rpc.hostdefi.com/api/v1/x402/rpc/arbitrum answers HTTP 402 with a payment challenge; pay 0.002 USDC and the call is served. Built for agents and machine clients; the endpoint is listed in the x402 bazaar.

curl -s -X POST https://rpc.hostdefi.com/api/v1/x402/rpc/arbitrum -H 'content-type: application/json' -d '{"jsonrpc":"2.0","id":1,"method":"eth_chainId","params":[]}'

API key — GET /api/rpc/keys/checkout returns the USDC payment addresses (Solana and Base); after paying, POST /api/rpc/keys/claim returns an rk1_* key to send as x-api-key on this endpoint. $25, one payment — the key does not expire.

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