ERC-20
Fungible token standard. Wallets surface transfers and approvals through transaction prompts; reads use eth_call.
Common methods: balanceOf, transfer, approve, allowance
Allowances
approve grants a spender permission to pull up to an amount from your balance. Allowances do not expire on their own; old unlimited approvals to deprecated contracts are a common risk.
| Method | What it does |
|---|---|
allowance(owner, spender) | How much the spender may still transfer for owner |
approve(spender, 0) | Revoke by setting allowance to zero |