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

# Slippage, Priority Fees & MEV

> Why your fill wasn't the price on the screen, and what each dial in Transaction Settings actually does to your money.

Why your fill wasn't the price on the screen — and what each dial in [Transaction Settings](/trading/transaction-settings) actually does to your money.

## Slippage

**What it is.** Between your click and your fill, other trades land and move the pool. Slippage tolerance = the worst price you'll still accept. Inside the cap → you fill at whatever it moved to. Outside → the trade reverts.

**The trade-off.** Tight slippage protects your price but fails your entries on volatile tokens. Loose slippage fills everything — including fills you'll regret. There is no "right" number, only the right number for the pool:

* Deep, established pool: 1–5%
* Young trenches token: 20–30% is honest about the volatility
* "It keeps failing, I'll set 50%+": stop and ask what you're chasing. A candle that outruns 30% slippage is a candle you're late to.

**The hidden risk of high slippage:** your tolerance is visible in the transaction. A 50% cap tells a sandwich bot exactly how much it can extract from you and still get your fill through. Which brings us to —

## MEV & sandwiches

**The attack.** Your pending buy is visible in the public mempool. A bot sees it, buys *before* you (pushing the price up), lets your buy land at the worse price, then sells into your fill. Their profit = your slippage budget. This is industrial-scale — tens of thousands of SOL are extracted from traders every month on Solana alone.

**The defense.** MEV protection routes your transaction privately to the block producer, so bots never see it in flight. Nothing to see = nothing to sandwich.

**The cost.** Private routing can land marginally slower than raw broadcast. For small fast punts that's a real trade-off; for size it isn't a question — keep protection on. Getting sandwiched on a \$5k buy costs more than any latency ever will.

## Priority fees

**What they are.** Chains process transactions in fee-priority order. The priority fee (tip) buys your place in line — critical on Solana during hot moments when everyone is trying to enter the same block.

**How to think about it.** Priority fees are the auction for *being early*, and their market price changes minute to minute. Trady's dynamic default tracks network conditions; raise it manually when a meta is running hot and fills are lagging. It goes to the network — paying more doesn't enrich the terminal, it just outbids other traders.

**The mistake to avoid:** paying a top-of-block priority fee to enter a token that already 5x'd is paying premium latency prices for a FOMO entry. Priority is for when *being 2 seconds earlier* is the edge — not a substitute for being right.

## How the three interact

A trench entry during a hot launch: **priority fee** gets you into the block early, **MEV protection** keeps bots from taxing you on the way in, **slippage** caps the damage if the pool moves anyway. Set as a preset once ([Filters & Presets](/discovery/filters-presets)), fire with one click ([Instant Trade](/trading/instant-trade-quick-buy-sell)).