Multi-chain RPC — one endpoint, every chain

Standard JSON-RPC 2.0 access to 40 blockchains through a single endpoint. No account, no API key, no monthly plan — pay $0.003 per call in USDC over x402. Built for AI agents that read on-chain data across many chains from one wallet.

BlockRun proxies upstream RPC gateways with x402 settlement, so an agent can query any supported chain without onboarding to a node provider.

The problem it solves

Traditional RPC providers (Alchemy, Infura, QuickNode) make you sign up, manage an API key, and pick a monthly plan with rate-limit tiers — per chain. An agent that needs Ethereum and Base and Solana and Polygon ends up with four accounts and four keys. BlockRun gives you one endpoint for 40 chains, paid per call, with on-chain settlement receipts.

Endpoint

POST /api/v1/rpc/{network}

Swap {network} for the chain. Body is a standard JSON-RPC 2.0 request; the response is returned verbatim from the upstream node. EVM (eth_*) and non-EVM (getSlot, …) methods both work. A JSON-RPC batch (array body) is priced per element. Upstream calls time out after 20 seconds.

Flat price: $0.003 per call ($0.002 base + the $0.001 transaction fee). No payment header → HTTP 402 quoting the exact price; add an x402 payment header (a wallet signature) → the result, settled in USDC on Base. Hot, low-volatility reads (eth_chainId, eth_getTransactionReceipt, getTransaction, …) are served from a short TTL cache — the X-Cache: HIT|MISS response header tells you which; writes and time-sensitive reads (eth_sendRawTransaction, eth_gasPrice, getLatestBlockhash) are never cached.

Supported networks (40)

EVM and non-EVM, one path each. A selection:

…and more. Slugs are case-insensitive. A malformed {network} (anything other than [a-z0-9-], up to 41 chars) returns 400 with the full curated list in supportedNetworks. A well-formed slug that is not in the curated list is still attempted as <slug>-mainnet against the upstream gateway (forward-compatible with newly added chains); if the chain does not exist there, the upstream 404 is relayed to you and nothing is charged. The live list is in /openapi.json, /.well-known/x402, and on /services/rpc.

Example

# Ethereum block number
curl -X POST https://blockrun.ai/api/v1/rpc/ethereum \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_blockNumber","id":1}'
# → 402 with price $0.0030 + Base USDC payment instructions
# Re-send with the x402 X-Payment header → {"jsonrpc":"2.0","id":1,"result":"0x..."}
#   response headers: X-Network: ethereum · X-Cache: HIT|MISS · X-Payment-Receipt: <tx hash> · X-Payment-Response: <base64>

# Solana slot
curl -X POST https://blockrun.ai/api/v1/rpc/solana \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"getSlot","id":1}'

Solana-only endpoint

There is also a cheaper Solana-only passthrough to public mainnet-beta:

POST /api/v1/solana/rpc

Same JSON-RPC body and x402 flow, $0.0015 per call ($0.0005 base + the $0.001 transaction fee), batches priced per element, 15-second upstream timeout. /api/v1/rpc/solana ($0.003) routes through the multi-chain gateway instead; either works for standard Solana JSON-RPC.

Errors

Every non-2xx body states "Payment was NOT charged" where it applies; settlement only happens after the upstream returns 2xx.

MCP

Via the BlockRun MCP server, agents call the blockrun_rpc tool: { network, method, params }.

What's next?