> ## Documentation Index
> Fetch the complete documentation index at: https://docs.blockrush.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Anti-MEV

> Reduce the risk of sandwich attacks by enabling BlockRush Anti-MEV transaction submission.

In Solana transaction acceleration, BlockRush provides Anti-MEV transaction submission to help users reduce the risk of sandwich attacks.

## Enabling Anti-MEV

To enable Anti-MEV protection, append `?anti_mev=1` to the transaction submission endpoint. Once enabled, BlockRush automatically adds the `jitodontfront` account required for Jito Sandwich Mitigation — no manual transaction modification needed.

### sendTransaction

```text theme={null}
http://ny.rpc.blockrush.io/?anti_mev=1
```

### submitBatch

```text theme={null}
http://ny.rpc.blockrush.io/submit-batch?anti_mev=1
```

<Note>
  If the endpoint already contains a `?` query string, append the parameter with `&anti_mev=1`.
</Note>

## What BlockRush Does Automatically

When `anti_mev=1` is enabled, BlockRush automatically adds a valid Solana public key starting with `jitodontfront` to the transaction. For example:

```text theme={null}
jitodontfront111111111111111111111111111111
jitodontfront111111111111111111111111111123
```

A transaction containing a `jitodontfront` account will only be accepted by the Jito block engine when it is the first transaction in the bundle. This prevents attackers from placing a front-run transaction before the user transaction.

You do not need to manually add `jitodontfront`. Simply add `anti_mev=1` to the BlockRush endpoint and BlockRush handles the rest.

<Warning>
  In rare cases, Anti-MEV protection may slightly delay transaction submission when avoiding high-risk leaders.
</Warning>

Anti-MEV protection cannot guarantee 100% avoidance of all MEV risks. We still recommend:

* Set reasonable and low slippage;
* Protect trading strategies and private key information;
* Avoid exposing sensitive transaction information in public environments.

## How Sandwich Attacks Happen

A sandwich attack is an MEV attack where an attacker intentionally places a user's transaction between two attacker-controlled transactions:

1. The attacker first sends a **front-run** transaction to buy or execute a related action before the user;
2. The user's normal transaction executes next;
3. The attacker then sends a **back-run** transaction to sell or execute the reverse action after the user's transaction completes.

By doing this, the attacker profits from the price movement caused by the user's transaction, while the user receives a worse execution price and incurs extra losses.

### Common Methods

**Using a Jito Bundle.** The attacker packages the front-run transaction, the user transaction, and the back-run transaction into the same Jito Bundle and submits it to a Solana validator. Bundle ordering guarantees make this attack stable.

**Using normal transactions for front-running and back-running.** The attacker monitors transaction propagation and quickly sends two normal transactions, placing them before and after the user's transaction. This depends on network speed, fee settings, and ordering capability — harder to execute, but does not fully depend on Jito Bundles.

## Why BlockRush Anti-MEV is Effective

### Automatically adding `jitodontfront`

Jito Sandwich Mitigation defends against bundle-based sandwich attacks. When a transaction contains a `jitodontfront` account, the Jito block engine rejects the bundle if that transaction is not the first one. This prevents attackers from placing a front-run transaction before the user transaction, reducing the risk of the user transaction being sandwiched.

With BlockRush, users only need to enable `anti_mev=1` — `jitodontfront` is added automatically, with no manual changes to transaction instructions.

### Anti-MEV submission path

After `anti_mev=1` is enabled, BlockRush processes the transaction through the Anti-MEV submission path, helping reduce the risk of MEV exploitation during transaction propagation and ordering. If the current submission environment is detected as high risk, BlockRush may adjust its submission strategy to further reduce the probability of a sandwich attack.

## Higher-security submission requirements

If you require stronger transaction protection or a customized secure submission path for a specific strategy, please [contact the BlockRush team](https://blockrush.io/contact) for support.