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Common issues and solutions when integrating with Custom Stablecoins swaps.

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Common Errors

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SwapsCannotBePaused

Error: Transaction reverts with SwapsCannotBePaused()Solution: Swaps are currently disabled on the contract. Wait for the PAUSE_ROLE holder to re-enable swaps.

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TokenNotListed

Error: Transaction reverts with TokenNotListed(address)Solution: The token address you provided is not listed on the contract. Verify the token address against the Key Addresses page.

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TokenMustBeSwappable

Error: Transaction reverts with TokenMustBeSwappable(address)Solution: The token is listed but currently disabled for swapping. Wait for the PAUSE_ROLE holder to re-enable the token.

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SlippageExceeded

Error: Transaction reverts with SlippageExceeded()Solution: The output amount after fees and decimal normalization is less than your minAmountOut. Increase your slippage tolerance or re-read the current feeBasisPoints() value and recalculate.

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AmountOutExceedsAvailableLiquidity

Error: Transaction reverts with AmountOutExceedsAvailableLiquidity(amountOut, availableLiquidity)Solution: Reduce your swap amount. The contract doesn’t have enough output token liquidity (after accounting for reserved amounts) to fulfill the swap.

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AddressNotInAllowlist

Error: Transaction reverts with AddressNotInAllowlist(address)Solution: The allowlist feature is enabled and your wallet address is not allowlisted. Contact support to be added.

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CannotSwapSameToken

Error: Transaction reverts with CannotSwapSameToken(address)Solution: You specified the same token address for both tokenIn and tokenOut. Use two different token addresses.

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ERC-20 approval errors

Error: Transaction reverts during transferFrom with no descriptive errorSolution: You need to approve the Stableswapper contract to spend your input tokens before calling swap(). Call approve() on the input token contract first:
const token = new ethers.Contract(tokenAddress, ERC20_ABI, signer);
await token.approve(STABLESWAPPER_ADDRESS, amountIn);

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Insufficient gas

Error: Transaction fails with insufficient funds for gasSolution: You need Base Sepolia ETH for gas fees. Get testnet ETH from CDP Faucet.

Production Readiness

Helper functions for validation

Examples

More swap code examples

Reference

Swap instruction parameters

Quickstart

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