Revoke a Risky Token Approval
A stale or malicious token approval lets a spender drain funds. This guide lists an address's approvals, then builds and simulates a revoke transaction so you cut the allowance to zero safely. Applies to ERC-20 approvals on eth.
- The address whose approvals you want to review.
- An API key with C2 access for data, build and simulate.
1List current approvals
Call the approvals endpoint to see every spender and its allowance. Flag unlimited allowances to unknown contracts.
curl "https://api.1st-node.com/v1/data/eth/address/0x8f2c.../approvals" \
-H "Authorization: Bearer sk_live_..."
> {"approvals":[{"token":"0xdac1...","spender":"0x7a1d...",
> "allowance":"unlimited"}]}2Build a revoke transaction
Build an approve call setting the allowance to zero for the risky spender. The build endpoint returns the raw payload to sign.
curl -X POST https://api.1st-node.com/v1/tx/eth/build \
-H "Authorization: Bearer sk_live_..." \
-d '{"from":"0x8f2c...","to":"0xdac1...","amount":"0"}'
> {"raw":"0x02f8...","gas_limit":"46000"}3Simulate then broadcast
Simulate to confirm the allowance drops to zero and there is no revert, then sign and broadcast the revoke.
curl -X POST https://api.1st-node.com/v1/tx/eth/simulate \
-H "Authorization: Bearer sk_live_..." \
-d '{"raw":"0x02f8..."}'
> {"success":true,"revert_reason":null}Perguntas frequentes
How do I find risky approvals?
List approvals for the address and flag unlimited allowances or unknown spender contracts. Those are the entries to revoke first.
Why simulate a revoke?
Simulation confirms the allowance resets to zero and the call will not revert or fall short on gas, so the revoke lands the first time.
Continue lendo
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