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Before any swap/bridge/zap that spends ERC20s, the DZap router must be approved. The SDK supports four modes — pick AutoPermit unless you have a reason not to.

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The four modes

ModeHowGasSpender
DefaultStandard ERC20 approve()Yes (one-time)DZap router
Permit2One-time approve to Permit2; sign per-tradeInitial yes, then signature onlyPermit2 contract
EIP2612PermitSign permit message; no approval txNone (signature only)DZap router
AutoPermitEIP2612 if supported, fallback to Permit2Best-of-bothAuto
Most modern tokens support EIP-2612 or are routable through Permit2, so AutoPermit covers the long tail.

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Check allowance

import { ApprovalModes } from '@dzapio/sdk';

const { status, data } = await dzap.getAllowance({
  chainId: 42161,
  sender: '0xUser',
  tokens: [{ address: '0xaf88...', amount: 1_000_000n }],
  service: 'swap',
  mode: ApprovalModes.AutoPermit,
});

// data['0xaf88...'] => { allowance: bigint, type: 'dzap' | 'permit2' | 'eip2612' }
type tells you whether the token will use a direct DZap approval, a Permit2 approval, or an EIP-2612 permit.

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Approve

if (data['0xaf88...'].allowance < 1_000_000n) {
  await dzap.approve({
    chainId: 42161,
    signer: walletClient,
    sender: '0xUser',
    tokens: [{ address: '0xaf88...', amount: 1_000_000n }],
    service: 'swap',
    mode: ApprovalModes.AutoPermit,
    approvalTxnCallback: ({ status, txHash }) => {
      console.log('approval', status, txHash);
    },
  });
}

​
Sign (gasless permits)

For EIP-2612 / Permit2 paths: 
const { data: permits } = await dzap.sign({
  chainId: 42161,
  sender: '0xUser',
  tokens: [{ address: '0xaf88...', amount: '1000000' }],
  service: 'swap',
  signer: walletClient,
});

// permits['0xaf88...'].permitData → pass to trade()/zap() as `permit`
1

Check

getAllowance() with mode: AutoPermit.
2

Approve or sign

If allowance < amount: approve() for on-chain or sign() for gasless.
3

Execute

Pass the permit payload (if any) into trade() / zap().

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Common pitfalls

  • Multi-token swaps — getAllowance and approve both accept arrays. Don’t loop one-by-one; you’ll trigger N wallet popups.
  • Service must match — service: 'swap' checks the swap router; service: 'zap' checks the zap router. They differ on some chains.
  • Permit deadlines — gasless permits include a deadline (default ~1 hour). Sign close to execution.
Last modified on May 4, 2026