# What is MEV and what is a sandwich attack on Solana?

> What is MEV? It is the profit from controlling transaction order on Solana. How a sandwich attack works, and how to read a ripr fill.

- URL: https://ripr.trade/blog/what-is-mev-sandwich-attack
- Publisher: ripr (https://ripr.trade)
- Author: ripr Editorial Team
- Published: 2026-11-08
- Category: Guides

If a trade on ripr filled worse than the quote you saw, a bot is not the first thing to suspect. What is MEV? MEV stands for maximal extractable value: the money someone can make purely from deciding which transactions go into a Solana block and in what order. A sandwich attack is the version traders actually feel, where a bot buys the same coin immediately before your buy and sells immediately after it.

So why did your transaction get front-run? Usually it didn't. Four plainer things explain nearly every fill that lands worse than the quote, and you can check all of them on ripr's own screens.

## What is MEV on Solana?

MEV on Solana is the profit available to whoever controls the order of transactions inside a block. Every trade you place on ripr becomes an ordinary [Solana transaction](https://solana.com/docs/core/transactions): ripr's in-house execution layer prepares it on its server, the app checks it on your device against the amount and slippage you chose, and your own wallet signs it. Where it then sits inside the block that carries it is decided by the validator building that block.

Ordering matters because a meme coin's price is set by the pool or curve it trades on, and every single fill moves that price. Two buys in the same block do not get the same price. Whichever lands first gets the better one, and that gap is the raw material for MEV.

## What is a sandwich attack?

A sandwich attack is two trades wrapped around yours: a bot buys the coin just ahead of your buy, lets your order push the price up, then sells into the higher price your order created. The bot's profit comes out of the price you ended up paying.

It only pays when your own order moves the price enough to cover the bot's costs, so pool depth decides everything. One coin in ripr's market data sat at a market cap near $33,000, trading on a single pool with about $270 of liquidity on each side. In a pool that thin, a buy of a fraction of a SOL already moves the quote.

In a deep pool, the same buy barely registers. That makes order size your first real decision, and the help centre explains [how your buy and sell size affect the price](https://ripr.trade/support/how-do-my-buy-size-and-sell-size-affect-price).

## Why your transaction got front-run

Most ripr trades that come in worse than the quote were never sandwiched at all. Front-running means somebody else's trade landing ahead of yours, and four things explain nearly all of these fills. Rule them out in this order.

1. **Your order was large for the pool.** A big buy against thin liquidity moves the price on its own, with no bot involved. The thinner the coin, the more likely your own order is the whole explanation.
2. **Time passed between the quote and your signature.** Quotes move while other people trade. If the price moves before you sign, ripr asks you to accept the new price instead of filling at the old one — the subject of the help-centre page on [why your quote is different from the one you saw moments ago](https://ripr.trade/support/why-is-my-quote-different-from-what-i-saw-moments-ago).
3. **Your slippage left room for it.** Slippage is the maximum price change you accept during execution, and any fill inside that ceiling is a valid fill.
4. **Somebody really did trade ahead of you.** When several hundred people buy one coin at once, orders land in front of yours constantly without anyone targeting you.

Solana has no public waiting room for pending trades, so there is no queue to watch. Transactions are forwarded to the validator building the current block, which is why front-running here depends on seeing or guessing your order as it happens, and why the next two sections are about evidence rather than suspicion.

## How your slippage setting decides what a sandwich can take on ripr

Your slippage setting on ripr is the ceiling on how much worse than the quote you will accept, so it also caps what one sandwich can take from a single order. Set it wide and there is room for a poor fill. Set it too tight on a fast-moving coin and the order may not go through at all. If you have never touched yours, start with the help-centre page on [what slippage is and how to set it](https://ripr.trade/support/what-is-slippage-and-how-should-i-set-it).

Auto slippage is on by default. It sets that ceiling from how much the coin moved over the last five minutes, between 3% and 15%, so a quiet coin gets a tight ceiling and a coin swinging hard gets a looser one. You can always set the number yourself.

Two more things happen before the trade leaves. On trades that route to a DEX pool, the transaction itself carries a minimum-output limit set from your slippage. And before your wallet signs, the app checks the prepared transaction on your device against the amount, slippage and fee limits you set, and refuses it if anything differs; that check is about the transaction matching what you asked for, not about the coin.

## How to read a ripr fill that came in worse than the quote

You can read a worse-than-quote fill on ripr's own coin page. The prices, charts and trades in ripr's apps come from its own in-house data layer, which decodes Solana transactions directly, so the evidence you need is already on the screen.

1. Open the coin from search. ripr finds any Solana coin by name, ticker or full contract address, and the address is the only one of the three that is unique to the coin.
2. Read the recent trades on the coin page. Each fill is pushed there as it is decoded, so you can see what landed around yours.
3. Look for the shape. A buy of similar size one or two trades ahead of yours, followed by a sell of almost exactly that size right behind it, is the sandwich pattern. A wall of unrelated buys is ordinary crowding.
4. Check your own numbers. The iOS and Android charts draw your entry line and trade markers, and both apps show your realized and open profit and loss over the last 7 or 30 days.

If the arithmetic still looks wrong, the help centre has a page on [why you received fewer tokens or SOL than expected](https://ripr.trade/support/why-did-i-receive-fewer-tokens-sol-than-expected).

## Front-running, sniping and bundled launches are not the same thing

Front-running happens to your order in flight, while sniping and bundled launches happen at a coin's birth. Sniping means buying in the first seconds of a launch, before most people have even seen the coin. A bundled launch is several buys pushed through in the same block as the coin's creation, which can leave a few wallets holding much of the supply before open trading starts.

ripr checks coins for those patterns when you open them, looking at linked wallets, coordinated or bundled launches and a creator keeping supply. Anything it finds shows up as a warning on the coin page and again in the buy flow, where it warns you rather than blocking the trade.

Those warnings are there to be read, and ripr's apps state their limit plainly: "These are the risks we can check for. Not seeing one never means a coin is safe." For the rest of that routine, read [how to spot a risky meme coin before you buy](https://ripr.trade/blog/how-to-spot-a-risky-meme-coin).

## Frequently asked questions

### What does MEV stand for?

MEV stands for maximal extractable value. It is the profit available from choosing which transactions enter a block and in what order, and on Solana it is the umbrella term that sandwich attacks and other kinds of front-running sit under.

### Is front-running the same thing as slippage?

No. Slippage is the price change you allow between the quote and the fill, and you set it yourself in ripr's trade sheet. Front-running is somebody else's trade landing ahead of yours, and it is one of several reasons a fill arrives inside your slippage instead of right at the quote.

### Do small trades get sandwiched?

A sandwich only pays a bot when your order moves the price, so a small buy in a deep pool is rarely worth the effort. In a pool holding a few hundred dollars a side, even a small buy moves the quote. That is one more reason to keep orders small on very thin coins.

## What to check on your next ripr trade

Two things decide most of your exposure to all of this, and you set both yourself: how big the order is against the pool, and how much slippage you allow. Keep the first order small on a thin coin, read the quote before you accept it, and sign promptly once it looks right. When you already know your size, the iOS quick-trade bar buys at your usual amount in one tap from the coin's page, with no confirmation sheet. If the order flow itself is still new to you, the walkthrough of [how to buy a Solana meme coin on ripr](https://ripr.trade/blog/how-to-buy-a-solana-meme-coin) covers it step by step.

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*Last verified 2 November 2026. This article is published by ripr, which builds an app for trading Solana coins. Nothing here is financial advice.*