Slippage

Slippage is the difference between the price a user sees when clicking “Swap” and the price the trade actually executes at. On an AMM-based DEX, slippage is normal: the pool price shifts as the swap is filled.

Where it comes from

If a TON/USDT pool holds 1000 TON and 5000 USDT, the spot price is 5 USDT per TON. A trader pulling out 100 TON drops the TON reserve to 900 and pushes the USDT reserve up (CPMM formula). The new price is no longer 5 USDT but closer to 5.55. That movement is slippage.

A real transaction adds a few extra sources:

• Thin liquidity. The smaller the pool versus your order, the bigger the move.
• Competing trades. Between the moment you sign and the moment your transaction lands, other trades can hit the same pool and shift the price.
• MEV / sandwich attacks. A bot sees your pending swap, buys ahead of you, waits for your swap, then sells — capturing part of your slippage.
• Multi-hop routes. If the swap routes through 2 to 3 pools (jUSDT to TON to DOGS, say), slippage accumulates per hop.

Tolerance: the wallet setting

To stop transactions from failing when slippage exceeds expectations, wallets expose a slippage tolerance — the maximum allowed deviation. If actual execution is worse, the contract reverts the swap.

Typical tolerances in TON wallets (Tonkeeper, MyTonWallet, the in-Telegram Wallet swap):

• Stable-stable (USDT/jUSDT): 0.1–0.3%. Prices barely move and a high tolerance just invites sandwich bots.
• TON to a major jetton (NOT, DOGS, HMSTR): 0.5–1%. Enough for normal volatility.
• TON to a small memecoin: 1–5% or higher. Pools are thinner, prices are more volatile.
• Multi-hop swaps: the same tolerance applies, but risks compound.

A loose tolerance is money left on the table for bots and arbitrageurs. Too tight, and you eat repeated failed transactions.

How to reduce slippage

• Split the order. Several smaller swaps over time instead of one large one.
• Route via an aggregator. A DEX aggregator splits the trade across pools so the combined move is smaller.
• Pick deep pools. TON/USDT is deeper than TON/random-memecoin — critical for size.
• Avoid volatile hours. Less volume, tighter spreads, fewer aggressive bots.
• Set a sensible tolerance. Match the realistic expected range, not a defensive 5%.

Slippage versus fee

These are different. The pool fee (typically 0.2–0.3%) is a fixed percentage taken from every swap. Slippage is a variable price move driven by depth and order size. Effective swap cost = fee + slippage + gas. On large trades, slippage usually dominates.

What to check before swapping

Every DEX and wallet quote screen shows a “Minimum received” line. That is your floor — anything below it reverts the trade. If the number is unacceptable, shrink the order, change the source of liquidity, or wait for a better moment.