Approve Token Spending
Allow a smart contract (DEX, protocol, etc.) to spend your tokens. Required before swaps, staking, or DeFi interactions. Set amount to 0 to revoke an existing approval.
Catalog action EVM Onchain wallet Gas
Allow a smart contract (DEX, protocol, etc.) to spend your tokens. Required before swaps, staking, or DeFi interactions. Set amount to 0 to revoke an existing approval.
This action can require a wallet connector, gas, token movement, or an external side effect. Test with simulation or a controlled amount before using it in a live workflow.
At a Glance
| Field | Value |
|---|---|
| Action ID | approve-erc20 |
| Category | EVM Onchain |
| Connector | wallet |
| Requires gas | Yes |
| Funds movement | None declared |
| Tags | blockchain, evm, erc20, token, approve, allowance, defi, permission, swap |
Payload Schema
| Field | Type | Required | Description |
|---|---|---|---|
tokenAddress | string | Yes | ERC20 token contract address |
spenderAddress | string | Yes | Address being approved to spend tokens (e.g., DEX router) |
amount | string | Yes | Amount to approve in token smallest units (e.g., "1000000" for 1 USDC). Use max uint256 for unlimited approval. |
chainId | number | Yes | Chain ID (1=Ethereum, 137=Polygon, 56=BSC, 8453=Base, etc.) |
gasLimit | string | No | Optional gas limit override |
confirmUnlimitedApproval | boolean | No | Required confirmation flag when approving unlimited (max uint256) amounts. Set to true to acknowledge the security risk. |
Result Schema
| Field | Type | Required | Description |
|---|---|---|---|
status | string | Yes | - |
transactionHash | string | Yes | - |
approvedAmount | string | No | The amount that was approved |
isUnlimitedApproval | boolean | No | Whether this was an unlimited approval (max uint256) |
blockNumber | number | No | Block number the transaction was included in |
Examples
json{ "type": "approve-erc20", "payload": { "tokenAddress": "0x0000000000000000000000000000000000000000", "spenderAddress": "0x0000000000000000000000000000000000000000", "amount": "1000000", "chainId": 8453 }, "children": [], "connector": { "type": "wallet", "id": "conn_wallet" }}
bashcurl -X POST "https://api.b3os.org/v1/actions/approve-erc20/test" \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "inputs": { "tokenAddress": "0x0000000000000000000000000000000000000000", "spenderAddress": "0x0000000000000000000000000000000000000000", "amount": "1000000", "chainId": 8453 }}'
Payload fields can use workflow expressions such as {{$trigger.body.amount}}, {{$nodes.fetch.result.price}}, and {{$props.asset}} when the value should come from a trigger, prior node, or reusable workflow prop.