{"uid":"cap_BNrnKFsffRlOxij__xP5u","slug":"riley-craig-x402-agent-store-chain-id-lookup-f98ce32e","name":"Riley Craig x402 Agent Store – Chain ID Lookup","description":"The EIP-155 chain ID for any supported network via eth_chainId — the read multi-chain agents make to confirm which chain an RPC is on before signing. Across Base, Ethereum, Optimism, Arbitrum, Polygon, Gnosis. Free public RPC; 6 chains vs onesource's Ethereum-only coverage.","url":"https://x402-agent-store.rileycraig14.workers.dev/chain/chain-id?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","properties":{"chain":{"type":"string","description":"base|ethereum|optimism|arbitrum|polygon|gnosis (default base)"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"chain_id":{"type":"number"}}}}}}},"responseSchema":{"type":"json","example":{"chain":"base","chain_id":8453}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.001","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.001/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.001","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_Kk_GO3mNHzVTQwbg-8bD3","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.001","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Returns the numeric chain ID for a specified EVM-compatible blockchain network (e.g. Base, Ethereum, Optimism)","exampleAgentPrompt":"What's the numeric chain ID for Optimism? I need it to configure my smart contract deployment.","exampleUseCases":null,"resultDescription":"A JSON object containing the canonical chain name string and its numeric EVM chain ID (e.g. {\"chain\": \"base\", \"chain_id\": 8453}). Costs $0.001 USDC per call via x402 on Base, no API key required.","failureModes":["Unsupported chain name returns an error or empty response","Invalid chain query parameter (typo or unsupported network) may return null or 400","Payment failure via x402 results in 402 Payment Required with no data returned","Cloudflare Worker downtime results in 5xx error"],"whenToPreferThis":"Choose this endpoint when an agent needs to programmatically resolve a human-readable EVM chain name (base, ethereum, optimism, arbitrum, polygon, gnosis) to its numeric chain ID without maintaining a local lookup table. Ideal for agents building transactions, configuring multi-chain tools, or validating network parameters at runtime. Particularly useful when combined with other x402 on-chain endpoints on the same store for a unified pay-per-call, no-signup workflow.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-28T18:34:48.616Z","isFirstParty":false,"canonicalSlug":"riley-craig-x402-agent-store-chain-id-lookup-f98ce32e"}