debug_traceTransaction on Optimism
Re-executes a transaction and returns a full execution trace (opcodes, call tree, or a custom tracer like callTracer). Essential for debugging reverts and MEV analysis. A heavy archive-grade method; needs a free API key.
Pick the tracer deliberately: callTracer gives a compact decoded call/transfer tree (what most people want), while the default struct logger emits opcode-level output that can be enormous. Old txs need archive state — the priciest method we serve.
Optimism endpoint (keyed — free)
https://rpc.nodeflare.app/op/v1/YOUR_KEYMethod
debug_traceTransaction
Cost
100 CU
Chain ID
10
Block time
~2 s
Finality
~2 s soft · L1-final ~13 min
Tracing on Optimism
debug_ tracing is supported. Pre-Bedrock blocks (before June 2023) come from the legacy system and don't trace like Bedrock blocks; deposit transactions (type 0x7e) trace without a mempool counterpart.
Parameters
[txHash, { tracer }]cURL
curl https://rpc.nodeflare.app/op/v1/YOUR_KEY \
-X POST \
-H 'content-type: application/json' \
-d '{"jsonrpc":"2.0","method":"debug_traceTransaction","params":["0x0000000000000000000000000000000000000000000000000000000000000000", {"tracer": "callTracer"}],"id":1}'ethers.js
import { ethers } from 'ethers';
const provider = new ethers.JsonRpcProvider(
'https://rpc.nodeflare.app/op/v1/YOUR_KEY'
);
const result = await provider.send('debug_traceTransaction', ["0x0000000000000000000000000000000000000000000000000000000000000000", {"tracer": "callTracer"}]);Try it live
Runs the example above against the public Optimism endpoint — straight from your browser.
debug_traceTransaction on Optimism — FAQ
How do I call debug_traceTransaction on Optimism?
POST a JSON-RPC 2.0 request with "method": "debug_traceTransaction" to NodeFlare's Optimism endpoint at https://rpc.nodeflare.app/op/v1/YOUR_KEY. This method requires a free API key — it is not available on the public endpoint.
What does debug_traceTransaction cost on the free tier?
debug_traceTransaction is weighted at 100 compute units per call. The free tier includes 2,000,000 CU/month, so that is roughly 20,000 debug_traceTransaction calls per month — no credit card.
Is debug_traceTransaction available on the public Optimism endpoint?
No. debug_traceTransaction is a heavy method and requires a free API key. The public no-key endpoint serves standard read methods; create a free key to unlock debug_traceTransaction, eth_getLogs, trace_* and debug_*.
Anything Optimism-specific to know when using debug_traceTransaction?
debug_ tracing is supported. Pre-Bedrock blocks (before June 2023) come from the legacy system and don't trace like Bedrock blocks; deposit transactions (type 0x7e) trace without a mempool counterpart.
Call debug_traceTransaction on Optimism with a free key
2,000,000 compute units/month, heavy methods unlocked, every chain included. No credit card.
Get your free API key →debug_traceTransaction on other chains