{"slug":"api-agentmercantile-com-v1-transaction-gas-preflight-c322e0","title":"Return bounded factual eth_estimateGas units and recent eth_feeHistory execution","host":"api.agentmercantile.com","method":"POST","resource":"https://api.agentmercantile.com/v1/transaction-gas-preflight","category":"code","description":"Return bounded factual eth_estimateGas units and recent eth_feeHistory execution-fee evidence for one unsigned Ethereum or Base transaction. Not execution, signing, custody, trading, or a guaranteed final cost. Call when you need point-in-time gas units and recent execution-fee context before signin","price_listed":0.005,"price_asked":0.005,"state":"answering","state_label":"Answering","checks_7d":1,"answered_7d":1,"latency_ms_median":232,"reported_calls_30d":2,"reported_payers_30d":2,"networks":["eip155:8453"],"badge":"unverified","paid_checks_7d":0,"paid_ok_7d":0,"example_input":{"body":{"chain":"eip155:8453","data":"0x","to":"0x0000000000000000000000000000000000000001","value_wei":"0"},"bodyType":"json","method":"POST","type":"http"},"output_schema":{"$schema":"https://json-schema.org/draft/2020-12/schema","properties":{"input":{"additionalProperties":false,"properties":{"body":{"additionalProperties":false,"properties":{"chain":{"description":"Analysis chain only. Payment remains Base eip155:8453.","enum":["eip155:1","eip155:8453"],"type":"string"},"data":{"description":"Optional 0x-prefixed even-length hex calldata. Default 0x. Maximum 8192 bytes. Request body maximum 20480 bytes.","maxLength":16386,"pattern":"^0x(?:[0-9a-fA-F]{2})*$","type":"string"},"from":{"description":"Optional 0x-prefixed 20-byte sender used only as an eth_estimateGas field. No ownership is implied.","pattern":"^0x[0-9a-fA-F]{40}$","type":"string"},"to":{"description":"Required 0x-prefixed 20-byte destination. Contract creation is not supported.","pattern":"^0x[0-9a-fA-F]{40}$","type":"string"},"value_wei":{"description":"Optional unsigned base-10 integer string in the uint256 range. Default 0. JSON Schema cannot express the full uint256 upper bound; runtime validation rejects values above 2^256-1.","pattern":"^(0|[1-9][0-9]*)$","type":"string"}},"required":["chain","to"],"type":"object"},"bodyType":{"enum":["json","form-data","text"],"type":"string"},"method":{"enum":["POST"],"type":"string"},"type":{"const":"http","type":"string"}},"required":["type","method","bodyType","body"],"type":"object"},"output":{"properties":{"example":{"additionalProperties":true,"properties":{"chain":{"type":"object"},"fee_history":{"description":"Recent eth_feeHistory execution-fee evidence.","type":["object","null"]},"gas_estimate":{"description":"eth_estimateGas units when estimable.","type":["object","null"]},"illustrative_execution_fees":{"description":"Illustrative L2 execution-fee observations, not a guaranteed final cost.","type":["object","null"]},"limitations":{"items":{"type":"string"},"type":"array"},"machine":{"enum":["VM06"],"type":"string"},"methodology_version":{"enum":["transaction-gas-preflight-0.1.0"],"type":"string"},"request_shape":{"type":"object"},"status":{"enum":["OK","PARTIAL","UNESTIMABLE","HOLD"],"type":"string"}},"required":["status","machine","methodology_version","chain","gas_estimate","limitations"],"type":"object"},"type":{"type":"string"}},"required":["type"],"type":"object"}},"required":["input"],"type":"object"},"history":[{"day":"2026-09-24","reachable":true,"status":402,"valid_402":true,"asked_usdc":0.005,"price_match":true,"latency_ms":232,"error":null}],"description_full":"Return bounded factual eth_estimateGas units and recent eth_feeHistory execution-fee evidence for one unsigned Ethereum or Base transaction. Not execution, signing, custody, trading, or a guaranteed final cost. Call when you need point-in-time gas units and recent execution-fee context before signing or submitting.","last_updated":"2026-09-17T03:59:00.452Z","schemes":["exact"]}