What is a Permit2 approval?#
Permit2 is an open-source token-approval contract that can safely share and manage token approvals across different smart contracts. A Permit2 approval gives a protocol permission to transfer tokens from your wallet.
Most tokens require an on-chain approval when swapping, and each protocol also requires its own approval. Every approval has a network cost, and those add up. Permit2 reduces this by letting approvals be shared and managed across different dapps, for a more unified and cost-efficient experience. Because it is open-source, any protocol — including CenturionDEX — can integrate it.
How it works#
Permit2 uses a two-step process:
- A one-time on-chain approval of the token, which requires a network cost. Approving a maximum amount once means you don't pay that cost on every swap.
- A signature approval, which gives the protocol permission to swap the tokens from your wallet. This has no network cost. The protocol sets which contract may spend the token, how much, and for how long. For example, CenturionDEX uses a limited-time approval of 30 days, after which you are prompted to sign a new one.
The risks#
Decentralized crypto requires you to manage your own funds, so read every warning and do your own research before signing.
With Permit2, it is especially important to verify what you sign. Because a signature requires no on-chain transaction, malicious actors can use a deceptive signature request (for example, a site asking you to "prove you own your wallet") to gain access to your tokens. Signing without reading carefully puts your wallet at risk. Read signature requests, verify the site is trusted, and confirm the permissions before signing.