---
title: "newFlashblockTransactions"
description: "Subscribe to receive each transaction the sequencer pre-confirms into a Flashblock, optionally with full transaction and log data."
source: https://basehub.org/api-reference/flashblocks/newflashblocktransactions/
---
Subscribe via `eth_subscribe` to receive each transaction as it is pre-confirmed into a Flashblock. Pass `true` as the second parameter to receive full transaction and log data.

Only available on Flashblocks WebSocket endpoints: `wss://mainnet-preconf.base.org` / `wss://sepolia-preconf.base.org`.

Requires [base/base](https://github.com/base/base) minimum client version v0.3.1.

Each subscription emits one item per WebSocket message, with events arriving roughly every 200ms. If your handler does heavy work per event, throttle or debounce it to avoid blocking.

## Parameters

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `subscriptionType` | string | Yes | Must be `"newFlashblockTransactions"`. |
| `full` | boolean | No | If `true`, each notification includes the full transaction object and associated logs. Defaults to `false` (minimal data only). |

## Returns

| Field | Type | Description |
| --- | --- | --- |
| `result` | string | Hex-encoded subscription ID. |

## Example

### Subscribe

```json
{"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newFlashblockTransactions"]}
```

### Subscribe (full data)

```json
{"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newFlashblockTransactions", true]}
```

### Subscription ID response

```json
{"jsonrpc": "2.0", "id": 1, "result": "0x1887ec8b9589ccad00000000000532da"}
```