ERC-20 Allowance Checker

Learn about token approvals and understand allowance risks

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Educational Tool

This tool helps you understand ERC-20 token allowances and their risks. It does not connect to any wallet or blockchain.

What are Token Allowances?

When you interact with DeFi protocols (like Uniswap, Aave, etc.), you often need to approve them to spend your tokens. This is called setting an allowance.

The Approval Flow:

You call approve(spender, amount) on the token contract
This allows the spender to transfer up to amount of your tokens
The spender can then call transferFrom() to move your tokens

Common Risks:

Unlimited Approvals: Many dApps request max approval (2^256 - 1)
Forgotten Approvals: Old approvals remain active even after you stop using a protocol
Malicious Contracts: Scam sites can drain your tokens if you approve them

Analyze an Allowance

Token Contract Address

Spender Address (Protocol/Contract)

Allowance Amount (in token units)

Enter the raw allowance value (paste from Etherscan or use common values below)

Common values:

Best Practices

• Only approve the exact amount you need for a transaction
• Revoke allowances for protocols you no longer use
• Use tools like Revoke.cash to manage your allowances
• Be extra cautious with unlimited approvals
• Verify contract addresses before approving