TX Hash Mode
Loading a Transaction
Select a network and enter a transaction hash. Load TX fetches the transaction metadata (from, to, value, calldata, block number) from the configured RPC endpoint. Public RPCs work for this step.
You can override the default RPC URL per network by editing the RPC Endpoint field before loading.
Replay & What-If Simulation
After loading, click Replay to re-execute the transaction via debug_traceCall. This requires an archive node with the debug API enabled (Alchemy, QuickNode, or your own node). Public RPCs usually don't support this.
You can edit the replay parameters (sender, recipient, calldata, value, gas, block number) before replaying. A faithful replay uses the original parameters; a simulated replay uses your modifications — useful for what-if analysis.
Shareable Replay Links
Copy Replay Link generates a URL containing only the parameters you changed. Paste it in a new tab to auto-load and replay the transaction.
No-TX-hash mode — you can also craft a URL with just ?to=...&data=...&blockNumber=...&network=... to open a pre-filled simulation form without needing an existing TX hash.
Supported URL parameters:
| Parameter |
Description |
| tx | Transaction hash |
| network | Network name (ethereum, base, arbitrum, optimism, bsc, polygon, etherlink) |
| rpc | Custom RPC URL |
| from | Sender address override |
| to | Recipient address |
| data | Calldata (hex) |
| value | Value in wei (hex) |
| gas | Gas limit (hex) |
| blockNumber | Block number (hex) |
| reverted | Set to 1 to include reverted transfers |
| USDPrice | Native token USD price for the current network. Alias for ETHUSDPrice. Case-insensitive. |
| <TOKEN>USDPrice | Per-token USD price: ETHUSDPrice (Ethereum, Base, Arbitrum, Optimism), BNBUSDPrice (BSC), MATICUSDPrice (Polygon), XTZUSDPrice (Etherlink). Case-insensitive. Multiple can be combined. |
Paste JSON / Upload File
Use the Paste JSON tab to paste a trace directly, or the Upload File tab to load a .json file (up to 50 MB). The format is auto-detected. You can paste the full JSON-RPC response or just the result object.
Supported Formats
1. Geth / Reth callTracer
curl -s -X POST YOUR_RPC_URL \
-H "Content-Type: application/json" \
-d '{
"jsonrpc":"2.0","id":1,
"method":"debug_traceTransaction",
"params":[
"0xYOUR_TX_HASH",
{"tracer":"callTracer"}
]
}' | jq . > trace.json
2. Forge test --json
forge test --mt test_my_replay -vvv --json > trace.json
3. Raw forge arena
[["Execution", {"arena": [...]}]]
Debugging Reverted Transactions
When a transaction reverts, the EVM rolls back all state changes — no transfers actually happen on-chain. However, the execution trace still records every call and transfer that would have occurred before the revert. This data is invaluable for debugging.
Include Reverted
Check Include reverted (next to the Analyze / Replay button) to visualize transfers from reverted calls. This affects:
- Transfer Graph — reverted transfers appear as dashed gray edges with reduced opacity, clearly distinct from successful transfers. Click an edge to see the revert reason (e.g. "insufficient balance for transfer", "execution reverted").
- Full Balance Changes — reverted balance deltas are shown in separate rows with a red left border and a REVERTED badge. Their checkboxes are disabled — they are never included in the "Selected" totals.
Key Delta Balances and the Invocation Flow are not affected by this toggle. Key Delta always shows the real on-chain outcome. The Invocation Flow already displays reverted calls with a red border and ✗ marker regardless of the toggle.
When to Use It
- A transaction fails and you want to see which token transfers were attempted before the revert.
- Debugging complex contract interactions where a sub-call reverts deep in the call stack.
- Understanding why a swap, liquidation, or arbitrage failed by inspecting the attempted flow.
This setting is preserved in shareable replay links (?reverted=1).
Result Panels
- Key Delta Balances — quick ETH/WETH summary for the main actors (sender, receiver, builder). Always shows the on-chain result. Enter a USD price in the Transaction Details header to see dollar equivalents (also used in balance change totals). This can also be set via URL:
?USDPrice=2050 or per token: ?BNBUSDPrice=600.
- Transfer Graph — interactive Cytoscape diagram of token and ETH flows between addresses. Supports step-by-step playback, layout options, gas edges, and optional reverted transfers.
- Full Balance Changes — net token deltas per address with profit/loss highlighting. Select addresses to compute combined totals.
- Events — decoded event logs from the trace.
- Invocation Flow — full call tree with decoded selectors, input/output data, gas per call, and inline revert reasons.
- Gas Profiler — per-call gas breakdown with flame-chart visualization.
