Guide · Tokens

How to swap ERC-20 tokens

Written by XAUConnect Labs · Reviewed against live product behavior · Updated August 2026

ERC-20 is the token standard on Ethereum and every EVM chain XAUConnect supports: BNB Chain, Polygon, Arbitrum, Base, Avalanche C-Chain. Swapping an ERC-20 always has the same skeleton — select chain, pick contracts, quote, approve, swap — and the details that hurt are always chain-specific gas and lookalike addresses.

If your token is SPL on Solana, this is the wrong article. If you want to create an ERC-20, that is Launchpad, not Swap.

The standard in one paragraph

An ERC-20 is a contract with balances and allowances. A DEX router cannot move your tokens until you grant an allowance (`approve`). Native coins (ETH, BNB, POL, AVAX) are not ERC-20s and skip that step. Wrapped natives (WETH, WAVAX) are ERC-20s and need it.

One standard, seven gas tokens

The contract interface is shared. The fee token is not. Ethereum charges ETH, Base and Arbitrum charge ETH too but at L2 prices, BNB Chain charges BNB, Polygon POL, Avalanche AVAX. Switching the chain selector without holding that gas token produces quotes you cannot send.

Allowance hygiene

Exact allowance for the size you intend to trade. Unlimited allowances linger. Revoke them later from a trusted explorer tool when you are done with a router. XAUConnect cannot revoke for you; that is another wallet signature.

Fee-on-transfer and rebasing tokens

Some ERC-20s tax transfers or rebase supply. Many aggregators and routers mis-handle them. If a token documents a transfer tax, expect failed simulations or worse fills. Honest XAUConnect Launchpad tokens do not include transfer tax — that is a reason to prefer them if you are the issuer, and a reason to read bytecode if you are the buyer of someone else’s token.

Execution checklist

Chain match. Contract paste. Gas buffer. Quote minimum received. Exact approve. Re-quote. Confirm. Explorer receipt. If you needed the token on another chain, bridge next — ERC-20s do not roam because the standard is shared.

Approvals you should revoke later

Every successful ERC-20 swap through a new router leaves an allowance. Exact allowances expire with the size you used. Unlimited allowances do not. After a campaign of trades, use a trusted explorer revoke tool — another signature, more gas, worth it on Ethereum if the spender set is large. XAUConnect cannot sweep your allowances; we never held the keys. Fee-on-transfer tokens may still fail even with a perfect allowance: the router’s minimum-received math assumed a full transfer.

Wrong chain, right standard

ERC-20 on the wrong chain is the empty-balance bug. The standard is shared; the ledger is not. Select Ethereum vs Base vs BNB before you approve. An allowance on Base does not spend Ethereum tokens. Paste the contract for the selected chain only.

Legal

Risk disclosure

XAUConnect is a non-custodial swap aggregator. Digital assets are volatile and may lose value rapidly. Content on this page is educational and not investment advice. Verify every contract address on the official block explorer before approving a transaction.

Frequently asked questions

Is USDC an ERC-20?

On EVM chains, yes. On Solana, USDC is an SPL mint. Same brand, different standard, different address format.

Can I swap ERC-20s without MetaMask?

Yes. Rabby, Coinbase Wallet, Rainbow, hardware wallets via those apps, and WalletConnect all work. You need an EVM account on the right chain.

Why two transactions?

First allowance, then swap, the first time you sell that token through that router. Later swaps reuse remaining allowance if it was enough — which is why unlimited approvals are risky.

How do I generate an ERC-20?

Use Launchpad: TokenFactory deploys a fixed-supply LaunchedToken (no mint, tax, or blacklist) for a small native fee. Then add liquidity so people can swap it.

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