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# debug_traceTransaction

# `debug_traceTransaction`

Tracer is required

On `rpc.linea.build`, the default tracer is **not supported**. You must specify a tracer in the options object. Supported tracers are `callTracer` and `prestateTracer`. `flatCallTracer` is not supported.

Replays a transaction and returns the execution trace. Useful for debugging failed transactions, analyzing internal calls, and inspecting state changes.

## Parameters

-   `transactionHash`: _[required]_ 32-byte hash of the transaction to trace.
-   `options`: _[required]_ Object specifying the tracer:
    -   `tracer`: _[required]_ `"callTracer"` or `"prestateTracer"`.

## Returns

Depends on the tracer:

-   **`callTracer`**: returns the call tree (nested `CALL`, `DELEGATECALL`, `STATICCALL` frames) with `from`, `to`, `gas`, `gasUsed`, `input`, `output`, and any nested `calls`.
-   **`prestateTracer`**: returns the pre-execution state of every account touched by the transaction: balances, nonces, code, and storage values.

## Example: `callTracer`

### Request

```bash
curl https://rpc.linea.build \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "debug_traceTransaction",
    "params": [
      "0x972fd73b83ee0d567143ebc67509d4fc98fa1b1941c2c145a342d3d10715c259",
      {"tracer": "callTracer"}
    ],
    "id": 1
  }'
```

### Response (abbreviated)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "from": "0xd26c8000ec8778de5257305c9acdd79f16f87867",
    "to": "0x6d7ac5d23266c9fea16463b877005bff6de531a7",
    "gas": "0x2635a",
    "gasUsed": "0x1458e",
    "input": "0x455ee4aa...",
    "output": "0x",
    "calls": [
      {
        "from": "0x6d7ac5d23266c9fea16463b877005bff6de531a7",
        "to": "0xc76cabfb0d247b4dc0b38b00b2ca92f8e8c9d32b",
        "gas": "0x1ee7d",
        "gasUsed": "0x12364",
        "type": "DELEGATECALL"
      }
    ],
    "type": "CALL"
  }
}
```

## Example: `prestateTracer`

### Request

```bash
curl https://rpc.linea.build \
  -X POST \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "debug_traceTransaction",
    "params": [
      "0x972fd73b83ee0d567143ebc67509d4fc98fa1b1941c2c145a342d3d10715c259",
      {"tracer": "prestateTracer"}
    ],
    "id": 1
  }'
```

### Response (abbreviated)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "0xd26c8000ec8778de5257305c9acdd79f16f87867": {
      "balance": "0x...",
      "nonce": 820300
    },
    "0x6d7ac5d23266c9fea16463b877005bff6de531a7": {
      "balance": "0x0",
      "code": "0x608060405..."
    }
  }
}
```