--- title: "Resolve the executing target for one Base transaction" method: POST path: "/v1/transaction/preflight" tags: ["Capabilities"] --- # Resolve the executing target for one Base transaction `POST /v1/transaction/preflight` ## Request - Base URL: `https://api.m2msentinel.com` - URL: `https://api.m2msentinel.com/v1/transaction/preflight` - Auth: one of: - API key in header `x-api-key` - HTTP bearer - API key in header `x-rapidapi-key` API-key/RapidAPI metered transaction-specific evidence. Accepts one strictly validated Base mainnet transaction, pins one observation block before state-bearing reads, identifies the supplied four-byte selector and resolved implementation or Diamond facet, returns bytecode hashes, capability evidence and an eth_call observation when possible. Incomplete or unsupported paths stay explicit. The caller owns policy before signing. This route is not x402-payable and has no x402 price; an unauthenticated request receives the normal protected-route 401 response. ## Request body - TransactionPreflightRequest - `chainId` union, required: Base mainnet only; decimal or canonical hexadecimal quantity. - 8453 - '8453' | '0x2105' - `to` string, required - `data` string, required: Even-length calldata. The shared HTTP JSON body limit is 32kb. - `from` string - `value` union - integer - string - `blockNumber` union: Optional explicit historical block. It is pinned exactly; latest is never used as a fallback. - integer - string ## Response `200` Verified or explicit bounded unverified transaction evidence. No safety, maliciousness, reachability, or exploitability conclusion is returned. - TransactionPreflightResponse - `status` 'SUCCESS' | 'UNVERIFIED', required - `operation` 'TRANSACTION_PREFLIGHT_OBSERVATION', required - `request` TransactionPreflightRequest, required - `chainId` union, required: Base mainnet only; decimal or canonical hexadecimal quantity. - 8453 - '8453' | '0x2105' - `to` string, required - `data` string, required: Even-length calldata. The shared HTTP JSON body limit is 32kb. - `from` string - `value` union - integer - string - `blockNumber` union: Optional explicit historical block. It is pinned exactly; latest is never used as a fallback. - integer - string - `selectorHex` string, nullable, required - `surfaceTarget` string, required - `surfaceTargetInfo` TransactionPreflightNode, required - `address` string, required - `bytecodeAvailable` boolean, required - `bytecodeSizeBytes` integer, required - `runtimeBytecodeHash` string, nullable, required - `resolvedExecutionTarget` string, nullable, required - `resolvedImplementation` string, nullable, required - `resolvedFacet` string, nullable, required - `completeResolutionPath` TransactionPreflightPathEdge[], required - union - object - `address` string, required - `from` string - `to` string - `via` string, required - `blockTag` string, required - object - `address` string - `from` string, required - `to` string, required - `via` string, required - `blockTag` string, required - `resolution` TransactionPreflightResolution, required - `status` 'COMPLETE' | 'NO_CODE' | 'UNRESOLVED' | 'UNRESOLVED_EIP7702_DELEGATION' | 'UNRESOLVED_EIP1167_TARGET' | 'UNRESOLVED_BEACON' | 'UNSUPPORTED_CUSTOM_DISPATCH' | 'AMBIGUOUS_PROXY_STATE' | 'CYCLE_DETECTED' | 'MAX_DEPTH_EXCEEDED' | 'DIAMOND_SELECTOR_UNAVAILABLE' | 'DIAMOND_SELECTOR_NOT_MOUNTED' | 'DIAMOND_RESOLUTION_INCOMPLETE' | 'RPC_READ_UNVERIFIED', required - `resolutionComplete` boolean, required - `proxyType` string, required - `proxyTypes` string[], required - `reason` string, nullable - `path` TransactionPreflightPathEdge[], required - union - object - `address` string, required - `from` string - `to` string - `via` string, required - `blockTag` string, required - object - `address` string - `from` string, required - `to` string, required - `via` string, required - `blockTag` string, required - `nodes` TransactionPreflightNode[], required - `address` string, required - `bytecodeAvailable` boolean, required - `bytecodeSizeBytes` integer, required - `runtimeBytecodeHash` string, nullable, required - `beaconAddress` string, nullable - `diamond` TransactionPreflightDiamond - `supportsInterface` boolean, required - `usedFacetsFallback` boolean, required - `facetCount` integer - `selectorCount` integer - `selector` string, nullable, required - `selectedFacet` string, nullable, required - `facets` TransactionPreflightFacet[], required - `address` string, required - `bytecodeAvailable` boolean, required - `bytecodeSizeBytes` integer, required - `runtimeBytecodeHash` string, nullable, required - `selectors` string[], required - `bytecodeHashes` TransactionPreflightBytecodeHashes, required - `runtimeBytecodeHash` string, nullable, required - `finalTargetBytecodeHash` string, nullable, required - `facetBytecodeHash` string, nullable, required - `facetBytecodeHashes` object[], required - `address` string, required - `runtimeBytecodeHash` string, nullable, required - `selectors` string[], required - `capabilityEvidence` TransactionPreflightCapabilityEvidence, required - `sourceAddress` string, required - `executionRole` 'RESOLVED_EXECUTING_CODE' | 'SELECTED_DIAMOND_FACET', required - `transactionSelector` string, nullable, required - `notASafetyGuarantee` true, required - `reachability` 'NOT_ESTABLISHED', required - `dissection` Dissection, required - `isValidContract` boolean - `bytecodeSizeBytes` integer - `targetBytecodeHash` string, nullable: Cryptographic SHA-256 hash of the analyzed bytecode - `capabilities` Capability[] - `type` 'DELEGATECALL' | 'SELFDESTRUCT' | 'MINT_SELECTOR' | 'PAUSE_SELECTOR' | 'FREEZE_SELECTOR', required - `confidence` 'HIGH' | 'MEDIUM' | 'LOW', required - `reachability` 'NOT_ESTABLISHED', required - `byteOffsetHex` string - `selectorHex` string - `snippetHex` string - `evidence` string, required - `detectedCapabilities` string[] - `metadata` object - `disclaimer` string - `simulationObservation` TransactionPreflightSimulationObservation, required - `attempted` boolean, required - `outcome` 'NOT_ATTEMPTED' | 'SUCCEEDED' | 'REVERTED' | 'UNAVAILABLE' | 'MALFORMED', required - `trusted` boolean - `returnData` string - `blockTag` string - `evidenceOnly` true, required - `error` object - `code` string - `message` string - `reason` string - `note` string - `evidenceGrade` boolean, required - `evidenceStatus` 'VERIFIED' | 'UNVERIFIED', required - `reason` string - `effectiveTrust` 'HIGH_TRUST_PRIMARY' | 'QUORUM_PUBLIC' | 'DEGRADED_LOW_TRUST', required - `observationBlock` TransactionPreflightObservationBlock, required - `status` 'PINNED' | 'UNVERIFIED', required - `chainId` 8453, required - `network` 'eip155:8453', required - `blockNumber` union, required - integer - string - `blockHash` string, nullable, required - `blockTag` string, nullable, required - `trustLevel` 'HIGH_TRUST_PRIMARY' | 'QUORUM_PUBLIC' | 'DEGRADED_LOW_TRUST', required - `providerName` string, required - `agreement` integer, nullable, required - `sampled` integer, nullable, required - `retrievedAt` string, date-time, required - `originalRetrievalTime` string, date-time, required - `headProvider` string - `reason` string - `note` string - `rpcObservation` TransactionPreflightRpcObservation, required - `pinnedBlockTag` string, required - `stateBearingCallCount` integer, required - `failedReadCount` integer, required - `failures` object[], required - `code` string, required - `message` string, required - `method` string - `calls` object[], required - `notASafetyGuarantee` true, required - `reachability` 'NOT_ESTABLISHED', required - `limitations` string[], required - `conclusion` unknown, required ## Other responses - `400`: The strict transaction preflight body failed validation before RPC, persistence, or quota work. - `401`: Missing or invalid credential, or a credential was supplied in the query string - `402`: The authenticated key has no remaining decision credit. This route does not offer an x402 challenge or price. - `405`: Verb not supported. HEAD is refused on protected routes because it would execute a metered handler while suppressing the body. - `429`: A plan burst limit or bounded public/intent retry limit was exceeded - `503`: A trusted pinned Base observation or required surface read was unavailable. No decision credit was consumed. --- [API](https://skmtc.dev/m2msentinel/apis/m2m-sentinel-base-contract-capability-checks-before-you-sign.md) · [All operations](https://skmtc.dev/m2msentinel/apis/m2m-sentinel-base-contract-capability-checks-before-you-sign/llms.txt) · [OpenAPI document](https://skmtc.dev/m2msentinel/apis/m2m-sentinel-base-contract-capability-checks-before-you-sign/revisions/2dadd4e704fd?raw)