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Before your first payment from a wallet on an EVM chain (Tempo included) or Tron, that wallet approves the Permit2 contract to spend the token you pay with. This is a one-time on-chain transaction per wallet and token. You don’t repeat it for every payment. Think of it like enabling autopay: you authorize once, and each payment then needs only your signature.

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How it works

  1. Once: your wallet sends a token approve (ERC-20, or TRC-20 on Tron) that lets Permit2 spend the token. This is the only step that costs you gas.
  2. Each payment: you sign the payment request. On these chains the signature is a Permit2 authorization for up to max_source_amount. It costs no gas.
  3. At the deposit: the settlement vault uses that authorization to take the selected quote’s source amount from your wallet, through Permit2.
Permit2 is Uniswap’s standard spending contract, not an Atum contract. Its address on each network is on Contract addresses.

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When you need to do this

  • The first time you pay with a given token from a given wallet on an EVM chain (Tempo included) or Tron
  • After switching to a new wallet
  • After a bounded approval runs out. An approval is unlimited by default, so this only happens if you chose a limit.

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How to complete it

The CLI and SDK read the current allowance first and only send a transaction when it falls short.

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Next steps

After you finish this page, the following go deeper: