Check the Token Approval Before a ParaSwap Swap

On an EVM network, swapping an ERC-20 on ParaSwap may require an on-chain approval that lets a spender contract move tokens from your wallet. Before confirming it, check the token, spender address and allowance amount.

Approval is a separate permission from the swap, and the spender may retain any allowance that the trade does not use.

Start with the source token and the network selected in your wallet: allowances are recorded by each token contract on each chain. ParaSwap can show an approval step if the existing allowance is below what the trade needs. If a transaction is pending or fails after approval, the linked paraswap guide covers diagnosis and retry steps.

What does a token approval authorize?

An ERC-20 approval sets an allowance: the amount a specified spender can transfer from the token holder’s address using transferFrom. The approval transaction calls approve(spender, amount) on the token contract; it does not itself move the tokens or execute the swap. The spender is the address receiving permission, not necessarily the exchange or liquidity pool shown in a route.

Check the approval request in your wallet against ParaSwap’s displayed transaction details. Confirm that the token contract is the source asset you intend to trade, that the spender address matches the one supplied for the trade, and that the amount is understandable. Do not assume a familiar token symbol proves the contract address is correct; different tokens can share similar names or symbols.

How do you decide how much to approve?

For a single trade, a finite allowance around the intended input amount limits the permission to that trade’s scale. A larger allowance can avoid another approval transaction for later swaps using the same token and spender, but gives that spender permission to transfer more of the token while the allowance remains available.

• Check the current allowance for your wallet, token contract and spender.
• If it covers the trade, an additional approval may not be needed.
• If it is short, approve only the amount you are comfortable authorizing.
• Review old allowances and reduce or revoke ones you no longer want to keep.

In ERC-20, a new approve call sets the allowance to its requested value, replacing the previous value; some tokens require setting it to zero before changing a non-zero allowance. Follow the wallet’s transaction details and token-specific behavior. A maximum allowance can reduce repeat approval steps, but it leaves broader permission in place than a trade-specific amount.

What should you check before signing the swap?

Wait for the approval transaction to confirm before submitting the swap when the interface requires it. The approval does not reserve a price: the quote can change while the transaction is pending, so check the route, input and expected output again before signing the trade. The approval may remain even if the swap is cancelled or fails.

Keep enough of the network’s native asset to pay gas for both transactions where needed. Native coin input does not use an ERC-20 allowance, while a wrapped version of that asset is an ERC-20 and can require one. The practical rule is to approve the exact source token and spender shown for the current chain, use a finite amount when repeat convenience does not justify broader access, and recheck the quote immediately before the swap.