Nov 1, 2026 · 2 mins read
Exact approvals, and what unlimited really costs
An approval outlives the swap that asked for it. Here is what it allows, and how to take it back.
An ERC-20 approval lets a contract move your token later, without asking again. Swapping needs one because the router pulls the token from you. The amount is yours to choose.
Why this site defaults to exact
An approval of exactly the swap amount is used up by the swap. Nothing stays open afterwards. It costs one more approval next time, which is the whole of the downside.
When unlimited is a choice
Some people trade the same token often and prefer to pay for one approval. That is a fair choice as long as it is a choice. Here it sits behind a box you tick, and the review prints it in capitals.
Permit2 has two layers
Uniswap v4 routes go through Permit2. The token allows Permit2, then Permit2 allows the router for an amount until an expiry. The site sets a 30-minute expiry on the second layer.
Taking it back
Setting an allowance to zero is an ordinary transaction. The permissions page lists what you have given to the venues this site can use, and writes the zero for you to sign. It cannot see approvals to contracts it does not know about.