Multi-chain RPC — every supported chain, one tool

blockrun_rpc POSTs a standard JSON-RPC 2.0 body to /v1/rpc/{network}. Flat $0.0030 per call ($0.002 base + the $0.001 transaction fee). A JSON-RPC batch array charges per element but pays the flat fee only once — $0.002 × n + $0.001, so a batch of 3 costs $0.0070 where three separate calls cost $0.0090. Batch whenever you can. Settlement in USDC via x402. Responses are cached briefly server-side for identical read calls (X-Cache: HIT is free of upstream latency but still billed).

When to use which tool

Networks

EVM (use eth_* methods):

Non-EVM (chain-native methods):

Unknown-but-wellformed slugs pass through to the Tatum gateway untouched — newly added chains work without an MCP update. A bad slug returns HTTP 400 with the supported list (no charge).

Recipes

ERC-20 balance (eth_call):

blockrun_rpc({
  network: "base",
  method: "eth_call",
  params: [{
    to: "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",   // USDC on Base
    data: "0x70a08231000000000000000000000000<ADDRESS_NO_0x_PADDED_TO_32B>"
  }, "latest"]
})

Native balance: method: "eth_getBalance", params: ["0x...", "latest"] Tx receipt: method: "eth_getTransactionReceipt", params: ["0x<txhash>"] Event logs: method: "eth_getLogs", params: [{ fromBlock, toBlock, address, topics }] — keep ranges small; huge ranges are rejected upstream (no charge). Gas: method: "eth_gasPrice" / eth_estimateGas

Solana token account: network: "solana", method: "getTokenAccountsByOwner", params: ["<owner>", {"mint": "<mint>"}, {"encoding": "jsonParsed"}]

Batch (charged per element, flat fee paid once — 3 calls = $0.0070, vs $0.0090 sent separately):

blockrun_rpc({ network: "ethereum", body: [
  { jsonrpc: "2.0", id: 1, method: "eth_blockNumber" },
  { jsonrpc: "2.0", id: 2, method: "eth_gasPrice" },
  { jsonrpc: "2.0", id: 3, method: "eth_chainId" }
]})

Failure semantics

• Upstream timeout / 5xx → no charge, retry safe.
• Malformed body / bad network → HTTP 400, no charge.
• JSON-RPC-level errors (e.g. revert on eth_call) come back inside result.error — the call is charged (the node did the work).