{"preview":true,"note":"Response shape only. The paid GET /rpc-capability-probe takes a JSON-RPC endpoint URL and reports whether archive state is readable and which of four methods are available. It first asks for a method that cannot exist, so that a refusal can be told apart from a fault - the same HTTP 403 means two different things depending on that control. Demand for this route is not measured.","example":{"endpoint":"https://arb1.arbitrum.io/rpc","reachable":true,"chain_id":"0xa4b1","latest_block":"0x1a2b3c4","archive":"no","archive_evidence":"missing trie node","refusal_style":"jsonrpc_error","methods":[{"method":"eth_getLogs","verdict":"supported","rpc_error_code":null,"http_status":200,"note":null},{"method":"trace_block","verdict":"not_supported","rpc_error_code":-32601,"http_status":200,"note":null}],"actionable":true,"detail":"Archive access: no. 2 of 4 probed methods are unavailable. This endpoint refuses unknown methods via a JSON-RPC -32601 error, which is how the results above were read.","checked_at":"2026-08-16T07:00:00.000Z"}}