Checking liquidity before a swap
- Author
- CRYPTO PORT Editorial
- Published
- Updated
- Reading time
- 6 min
In short
On a DEX, the larger your trade relative to the money sitting in the pool, the worse the amount you receive. Being able to buy does not mean you will be able to sell the same amount back. Before swapping, make it routine to look at the pool's size, how much genuinely trades, and what your own size does to the price.
Key points
- In a thin pool even a small order moves the price, and a round trip loses value
- The price impact figure tells you how far your own size moves the price right now
- A large amount of value locked is not proof of safety or of worth
- Buying and selling are separate questions — check that an exit route exists
Definition
Examining the size and depth of the liquidity pool a token trades in, before you swap, in order to estimate how unfavourable a price your own order will cause.
Start with the mechanism. On an AMM, price comes from the ratio of the two tokens held in the pool. Putting one in and taking the other out changes that ratio, and the change in ratio is the change in price. A deep pool barely shifts; a small one moves a long way on the same order. That is all 'thin liquidity hurts' means.
Begin with the numbers the swap screen already gives you. Alongside the expected output, interfaces generally show price impact. A large figure there is telling you your size is too big for the pool. Reduce the amount and watch how it changes — that shows you what size the pool can actually absorb.
Then look at the pool itself. Analytics sites and a DEX's own pool listings show the value deposited and the volume traded over a period. A pool holding a lot of value but trading almost nothing means nobody is really buying or selling. Conversely, volume that dwarfs the deposits can indicate wash trading manufacturing the figure. Never judge on one number alone.
The step people skip is checking the exit. A route in does not guarantee a route out. Because liquidity providers can withdraw at any time, a pool can thin out or vanish quickly, and if the issuer or a handful of addresses hold most of the liquidity, the moment that money leaves you can no longer sell.
Finally, what this check can and cannot tell you. Liquidity analysis never answers 'is this token safe'. It answers 'how bad a price does my size get right now' and 'how narrow is the exit'. Authenticity is a separate procedure, and if that one comes back unconfirmed, no amount of depth makes the trade sensible.
Watch out for
- · Liquidity providers can pull out whenever they like. Pools that disappear right after people buy in — rug pulls — are a real and recurring event
- · A large amount of value locked is not evidence of an audit, nor of trustworthy operators
- · Some tokens are written to charge punitive fees only on sales, or to refuse sales from all but privileged addresses. Buying successfully guarantees nothing about the exit
Frequently asked questions
Are price impact and slippage tolerance the same thing?
No. Price impact is the disadvantage your own order creates, and it is known before you execute. Slippage tolerance covers movement caused by other people's trades between submission and execution. You shrink the first by trading less; you change the second in settings.