© 2026 Della Group. All Rights Reserved.
Okay, picture this. I'm swapping some USDC for ETH on Uniswap, feeling all smart about my DeFi moves. Wallet pops up: "Approve unlimited USDC?" I click yes because I'm lazy and it's just easier. Fast forward a month. Some shady dApp I messed with once gets hacked. Boom - my entire USDC balance drained. Gone. Sound familiar? Yeah, that's token approvals biting you in the ass. Happened to me, and honestly, it sucked. But now I got this down, and I'm sharing so you don't repeat my dumb mistake.
The thing is, token approvals let DeFi apps - like DEXs, lending spots, or yield farms - move your tokens for you. Without 'em, you'd sign every tiny transfer, which is gas hell. But unlimited approvals? That's like handing your house keys to a stranger. They can spend all your tokens anytime, even after you're done with the app. If that contract gets exploited? Kiss your funds goodbye.
Super simple. You hold ERC-20 tokens - think USDC, DAI, UNI - in your wallet like MetaMask. A DeFi protocol needs permission to grab some for a swap or deposit. You call the approve function on the token contract. Tells it: "Hey, let this spender address move up to X amount from me."
Then the spender uses transferFrom to actually move the tokens. And allowance lets anyone check how much is left approved. Costs gas, like ~20k-50k on Ethereum, way less on cheaper chains like Solana or Base (~0.000005 SOL per tx). But once approved, it sticks around forever unless you revoke it.
Why do protocols ask for unlimited? Convenience. No re approving every trade. Saves gas over time. But in my experience, it's a trap. I now always set exact amounts, like if I'm swapping 100 USDC, approve 100. Not infinity.
Unlimited approvals are the big one. Protocols like old Uniswap versions default to it. Hackers love it - one exploit, and they drain everything. Remember that Ronin hack? Approvals played a part in similar messes.
Then there's approval phishing. Fake sites mimic legit DEXs. You approve, they steal. Or front running: You try to lower an approval from 100 to 50 tokens. Attacker sees it pending, front runs with transferFrom for the full 100 first. Brutal.
Question is, why risk it? One revoke costs like 50k gas (~$2-5 on ETH), but saves your stack.
I usually hit up a few go tos. De.Fi Shield scans your wallet, flags risky approvals, revokes in batch. Connect MetaMask, boom - sees everything across chains. TokenGuard does similar, one click scans. Utila extension even overrides dApp requests, caps approvals automatically.
Free ones? Etherscan. Go to a token page, "Read Contract," punch in your address and spender. Shows allowance. Do it manually if you're old school. Or Revoke.cash - clean UI, supports EVM chains, Tron too.
| Tool | What it does best | Gas cost example | Chains |
|---|---|---|---|
| De.Fi Shield | Risk scan + batch revoke | ~30k gas/revoke | EVM, Solana |
| TokenGuard | Real time monitoring | Batch saves 50% | Ethereum mainly |
| Revoke.cash | Simple revokes | ~40k ETH gas | Multi EVM |
| Utila Extension | Overrides approvals | Prevents upfront | Browser wallets |
Pro tip: Use these weekly. I set a calendar reminder. Takes 5 mins, peace of mind forever.
Before you approve anything new. Always.
What's next after? Revoke immediately if one off. Don't leave it hanging.
That MetaMask screen freaks people out. It says "Spend unlimited?" Yeah, ignore that. Click "Edit" - set your number. On mobile? Trust Wallet or Rainbow same deal. Gas fee pops up - if it's over $10 on ETH, wait for L2 or cheaper times.
Now, the cleanup. I do this every Friday, coffee in hand.
Head to Revoke.cash or De.Fi Shield. Connect wallet. Boom - list of all approvals. Red flags for unlimited or risky contracts. Sort by amount or date.
Issue? Gas too high? Wait. Or use L2 like Arbitrum - approvals work same, cheaper. Tron? Similar, but check Tronscan.
In my experience, after first cleanup, you'll find 10-20 dusty approvals. Shocking how they sneak up.
Not all blockchains same. Ethereum mainnet? Gas wars. But approvals identical across EVM: Polygon, BSC, Optimism.
Solana? Different. Uses "sign and delegate" but similar risks. Tools like Solana Explorer or Solflare wallet show delegations. Revoke via wallet.
Tron? USDT king there. Approvals via Tronscan, same approve/transferFrom.
Don't put everything in one wallet. I run three:
Hot wallet: Daily trades, small balance. Revoke often.
Cold wallet: Hardware like Ledger. Only bridge in what you need.
Burner wallet: High risk stuff. New protocol? Send 0.1 ETH there first.
Extensions? Utila overrides bad requests. Trust Wallet has built in scanners now.
Question: Ever FOMO into a new farm? Use burner. Limits damage.
Batch everything. Tools like Multicall let you revoke multiple in one tx - gas down 70%.
Monitor with alerts. De.Fi pings if new risky approval detected.
Whitelist spenders. Some wallets let you pre approve trusted contracts only.
Gas optimization: Revoke during low network times. Tools show live gwei - aim under 15.
Numbers: Unlimited approval? That's 2^256 -1 tokens. Insane. Stick to specifics: for 1 ETH trade (~$3k), approve 1.1 ETH worth.
Same shit. OpenSea asks "approve all?" No. Set per collection or revoke post sale. Tools like De.Fi cover NFTs too.
One: "Approval failed." Gas too low? Bump it 20%.
Two: "Still draining after revoke?" Check chain. Multi chain approvals? Revoke everywhere.
Three: Phishing stole already. Sweep remaining tokens to new wallet. Lesson learned.
Four: High fees. Switch to Base/Blast - approvals identical, gas ~0.01 ETH equiv.
Honestly, most issues? User error. Verify twice, approve once (exactly).
Make it routine. After every DeFi sesh: Check approvals, revoke extras.
Use hardware for big bags. Separate hot/cold.
Follow security Twitter. Hacks drop daily - approvals often culprit.
© 2026 Della Group. All Rights Reserved.