How to spot a sandwich attack

What a sandwich attack is

A sandwich attack is a bot bracketing your swap to make you fill at a worse price. Learning to spot it is about recognizing the early, observable signals before the crowd does.

The signals that matter

When you are spotting a sandwich attack, these are the concrete signals to focus on:

• A fill noticeably worse than the quote
• Two bracketing trades around yours
• High slippage tolerance on a thin pool
• A large, visible pending swap
• Repeated bad fills at size

Where to look

You will mostly observe a sandwich attack in the difference between your quote and realized fill, and the surrounding transactions. To spot it reliably, go straight to these sources rather than relying on chat or hype.

To spot it reliably: the steps

1. Establish the token's normal baseline so you can see deviations.
2. Scan for the signals above, especially the earliest ones.
3. Confirm with a second signal before concluding — one alone can mislead.
4. Note where you are relative to the crowd; early beats late.

The mistake almost everyone makes

Turning the read into action

Knowing the theory around a sandwich attack is necessary but not sufficient. The traders who consistently act on it have collapsed their recognition lag — usually with alerts that flag the relevant conditions in real time, leaving them free to focus on judgment and execution.