If you are an active DeFi user, you have likely encountered this tedious process countless times. Every time you interact with a new decentralized application (dApp), you are required to approve that dApp to spend your tokens.
This experience, often seen through interfaces like MetaMask, feels analogous to setting up a direct debit in traditional finance—where you authorize a utility company to withdraw funds from your bank account monthly.
However, unlike the crypto space, traditional direct debit systems involve only a limited number of trusted entities. These companies are less likely to engage in fraudulent activities, and users have recourse through dispute mechanisms managed by banks. In the crypto world, such safeguards are largely absent. Many dApps are built by anonymous developers, and there is no mediation system for users who fall victim to scams. Once a transaction is confirmed on the blockchain, it is irreversible.
What Are Token Approvals and How Do They Work?
Most tokens on the Ethereum blockchain, such as USDC and DAI, follow the ERC-20 standard. ERC-20 tokens are essentially smart contracts that include various methods like transferFrom and burn. Users trigger these methods to execute actions involving their tokens.
One critical method is approve. For any dApp to interact with your ERC-20 tokens, it must first obtain permission. For example, if you want to deposit USDC into Aave, you must approve Aave’s smart contract to access your USDC before initiating the deposit transaction. This approval is visible in your Ethereum wallet interface.
While approvals can theoretically be set to specific amounts, many dApps request unlimited authorization by default. This simplifies the user experience and reduces the number of transactions needed. However, it introduces significant risks: users often believe they are approving a one-time, limited transaction, but in reality, they may be granting permanent and unrestricted access to their tokens.
If a dApp is compromised or malicious, attackers can exploit these approvals to drain all authorized tokens from users’ wallets—without requiring further consent. Such attacks can occur at any time, even years after the initial approval.
How to Protect Yourself
The good news is that you can take steps to safeguard your assets. Below, we explore methods for managing approvals with standard Ethereum wallets like MetaMask, as well as advanced solutions offered by smarter wallet designs.
Manually Revoking Token Approvals
To manually revoke approvals, you can use tools like Token Allowance Checker. These tools connect to your wallet and scan the blockchain to identify all existing dApp approvals linked to your Ethereum address. You can then adjust these approvals—either reducing them to zero to revoke access or setting a specific limit you are comfortable with.
Each adjustment requires an on-chain transaction, incurring gas costs. Despite the expense, regularly auditing and revoking unnecessary approvals is a recommended security practice.
👉 Explore real-time gas tracking tools
Pro Tip: To minimize costs, consider using gas tracker browser extensions. These allow you to monitor network fees and execute transactions when gas prices are low.
How Next-Generation Wallets Enhance Security
Smart contract wallets introduce advanced features that improve both security and user experience. Their programmable nature allows for customized interaction methods with dApps, including more granular control over approvals.
Native Integrations: The Argent Example
Argent, a mobile Ethereum wallet, natively integrates several core DeFi applications. This allows users to lend, borrow, earn yield, and trade directly within the app.
Because these integrations occur at the smart contract level, dApps only receive approval for the exact amount needed for each transaction. This process happens automatically, so users may not even notice the approval step.
WalletConnect and Flexibility
A limitation of native integrations is scalability—it’s impractical for a wallet to integrate every DeFi protocol. While Argent covers many popular dApps, power users often interact with dozens of different applications.
WalletConnect addresses this by enabling users to connect mobile wallets to web-based dApps securely. Argent’s implementation of WalletConnect includes features for setting custom approval limits and one-click revocation of permissions. Since most dApps support WalletConnect, this offers a secure way to explore the broader DeFi ecosystem.
Batch Transactions and dApp Keys: The Authereum Model
Authereum is a web-based smart contract wallet that supports most Ethereum dApps. It uses traditional email and password login, offering a familiar user experience without sacrificing security.
When interacting with a dApp, Authereum generates a temporary dApp key for signing transactions. This key has limited capabilities, and Authereum performs integrity checks—for example, blocking requests from unauthorized domains. Users can delete dApp keys at any time.
Another advantage is transaction batching. Sending multiple actions in a single transaction reduces gas costs and saves time. A standard Ethereum transfer costs about 21,000 gas. Bundling ten transactions could save up to 189,000 gas. However, this requires dApps to implement custom logic and UI flows. Currently, only a few dApps like 1inch and Erasure support batching, but wider adoption is expected.
Frequently Asked Questions
What is a token approval?
A token approval is a permission you grant to a dApp, allowing it to access and transfer a specific amount of tokens from your wallet. This is necessary for interactions like swapping, lending, or staking.
Why are unlimited approvals risky?
Unlimited approvals grant dApps permanent access to your tokens. If the dApp is hacked or malicious, attackers could drain all approved tokens from your wallet without your consent.
How can I check my current approvals?
You can use tools like Token Allowance Checker or Etherscan’s Token Approval tool. These platforms scan your wallet address and display all active approvals along with the granted limits.
Can I change an approval after granting it?
Yes. You can revoke an approval entirely by setting the limit to zero or reduce it to a specific amount. Each change requires an on-chain transaction and gas fee.
Are smart contract wallets safer?
Yes. Smart contract wallets like Argent and Authereum offer enhanced security features such as customizable approvals, one-click revocations, and transaction batching. They reduce risks associated with unlimited approvals.
Do all dApps require token approvals?
Most dApps that interact with your tokens require approvals. However, the type and scope of approval can vary. Some wallets and dApps are adopting finer-grained control to improve security.
Conclusion
Token approvals represent a significant security challenge and usability barrier in the crypto industry. Improving this mechanism is essential for enhancing both safety and user experience.
Innovative wallets like Argent and Authereum demonstrate that safer dApp interactions are possible through smart contract functionality. However, broader adoption depends on dApp developers implementing supporting features.
For users of standard Ethereum wallets, regularly reviewing and managing approvals is a critical security habit. Tools for checking allowances are helpful, but greater awareness and built-in wallet features are needed to protect all users.
The evolution of approval mechanisms will play a key role in making decentralized finance more accessible and secure for everyone.