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TraceFast Transaction Failures
x402
TraceFast Transaction Failures is a paid API for AI agents from mpp.tracefast.xyz, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-12).
Returns all failed call frames within a reverted Ethereum transaction, including their position in the call tree, caller/target addresses, failure kind, revert payload, and decoded error name.
Price / call$0.01
Success—
StatusUnknown
How this service works
TraceFast live Ethereum data: the failed call frames of a reverted transaction — for each, its position in the call tree, caller and target, the kind of failure (revert, panic, custom error, out of gas, …), the revert payload with its selector, and the error name when the selector is known. Path hash: Transaction hash, `0x`-prefixed, 64 hex characters, any case. Docs: https://docs.tracefast.xyz/api/transaction-failures.md
Output
A list of failed call frames from the reverted transaction, each containing: its position in the call tree, the caller and target contract addresses, the type of failure (revert, panic, custom error, out of gas, etc.), the raw revert payload with its 4-byte selector, and the human-readable error name when the selector is recognized.
Example use cases
Debugging a failed DeFi swap
“This Uniswap swap transaction 0x7f3a1c9b4e2d8f0a6c5b3e1d9a7f4c2b8e0d6a3f5c1b9e7a2d4f8c0b6e3a1d9f failed — can you show me every call frame that reverted, which contracts were involved, and what the actual revert reason was?”
Smart contract audit failure analysis
“I'm auditing a contract and need to understand this failed transaction 0xa1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2 — give me the full list of failed call frames, their positions in the call tree, and any custom errors or panics that were raised.”
Alerting on recurring contract reverts
“For the transaction 0x2d4f8c0b6e3a1d9f7c5b3e1a4f8c6b0d3e9a7f5c2b1d8e6a0f3c7b4d9e2a7f3 that just reverted, what failure types were triggered and which caller-target pairs are responsible — I want to know if it was an out-of-gas or a custom error so I can set up the right alert.”
Technical details
Endpoint
GEThttps://mpp.tracefast.xyz/api/v1/chains/1/transactions/:hash/failures?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to debug or analyze a specific reverted Ethereum transaction and want structured, decoded failure information for every failed call frame — especially when you need to distinguish between revert types (custom error, panic, out of gas) and decode error selectors into human-readable names. Prefer this over generic RPC trace calls when you need pre-processed, structured failure data without parsing raw trace output yourself.
Side effects
- Invalid or malformed transaction hash returns a 400 error
- Transaction hash not found on Ethereum mainnet returns a 404
- Transaction that succeeded (not reverted) may return an empty failure list
- Network or RPC issues may cause intermittent 500 errors
- Payment not included or insufficient USDC via x402 protocol returns 402
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| input | — |
Tags
x402
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