Replay transaction trace (Parity-style)

POST /v1/polygon/trace/replay-tx replays a transaction that has already been included in a Polygon block and returns its Parity-style (trace_*) output. It is the canonical way to understand exactly what a transaction did on-chain: the tree of internal calls it made, the gas each frame consumed, where it reverted, and — when requested — the full VM step trace and the set of state changes it produced.

You choose what to compute with the tracers array. Pass trace (the default) for the flat list of call frames, vmTrace for the step-by-step VM trace, and stateDiff for the before/after state delta. You can request any combination; each requested tracer adds its own top-level key to the response envelope, and keys you did not request are returned as null.

Exclusive availability. Triport exposes the only freely available Polygon Parity-trace canal — equivalent access elsewhere is gated behind paid plans. Because tracing is computationally heavy and the upstream canal is rate-constrained, this endpoint requires the Pro tier and above and is rate-limited per tier. Trace only the transactions you genuinely need to inspect.

Request body (application/json):

The response is the Parity-style trace envelope. The example below is the result for the default ["trace"] request — vmTrace and stateDiff are null because they were not requested.

See the shared error envelope reference for the full error object shape and handling guidance.

JavaScript (fetch)

const res = await fetch("https://api.triport.io/v1/polygon/trace/replay-tx", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.TRIPORT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    tx_hash:
      "0x5b8d2a3c9f1e7b04c6f2a1d8e3047b9a6c1f0e2d4b8a7c5e9f3a1d2c4b6e8f0a",
    tracers: ["trace"],
  }),
});


const envelope = await res.json();
console.log(envelope.trace?.length ?? 0, envelope.output);

TypeScript SDK (@triport/sdk)

import { Triport } from "@triport/sdk";


const triport = new Triport({ apiKey: process.env.TRIPORT_API_KEY! });


const envelope = await triport.polygon.trace.replayTx({
  tx_hash:
    "0x5b8d2a3c9f1e7b04c6f2a1d8e3047b9a6c1f0e2d4b8a7c5e9f3a1d2c4b6e8f0a",
  tracers: ["trace", "stateDiff"],
});


console.log(envelope.trace, envelope.stateDiff);

Python (triport-sdk)

import os
from triport import Triport


triport = Triport(api_key=os.environ["TRIPORT_API_KEY"])


envelope = triport.polygon.trace.replay_tx(
    tx_hash="0x5b8d2a3c9f1e7b04c6f2a1d8e3047b9a6c1f0e2d4b8a7c5e9f3a1d2c4b6e8f0a",
    tracers=["trace"],
)
print(len(envelope["trace"]), envelope["output"])

• Request only the tracers you need. vmTrace and stateDiff are substantially larger and more expensive than the default trace; adding them to every call will exhaust your tier's RPS budget faster.
• The transaction must already be mined. To trace a hypothetical call that has not been sent, use POST /v1/polygon/trace/call, which takes a full tx payload and a block tag instead of a tx_hash.
• The trace output is a pass-through Parity-style envelope; fields beyond those documented above may appear depending on the requested tracers, so decode it defensively.
• This endpoint covers Polygon PoS. For Ethereum execution traces, use the Ethereum debug-namespace methods such as debug_traceTransaction.