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Portal’s Flutter SDK provides token delegation capabilities through the portal.delegations API. This enables approving token spending, revoking approvals, checking delegation status, and transferring tokens as a delegate on both EVM and Solana chains.

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Overview

The delegations functionality allows you to:
  • Approve other addresses to spend tokens on behalf of your wallet
  • Revoke existing delegations to remove spending permissions
  • Check status of active delegations and balances
  • Transfer tokens as a delegate from another address

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Prerequisites

Before using delegation operations, ensure you have:
All examples below assume Portal has already been initialized with await portal.initialize(apiKey: 'YOUR_API_KEY'). See Getting Started for details.

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Approving Delegations

Use approve to grant another address permission to spend tokens on your behalf. This method works for both EVM and Solana chains.

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EVM Approval

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  // Approve a delegate to spend USDC on your behalf
  final response = await portal.delegations.approve(
    chain: 'eip155:11155111', // Sepolia testnet
    token: 'USDC',
    delegateAddress: '0xa944e86eb36f039becd1843132347eb5b8501562',
    amount: '0.01',
  );

  // Sign and send the transaction
  final tx = response.transactions!.first!;
  final txResponse = await portal.request(
    chainId: 'eip155:11155111',
    method: 'eth_sendTransaction',
    params: [
      {'from': tx.from, 'to': tx.to, 'data': tx.data, 'value': tx.value}
    ],
  );
  print('Tx hash: ${txResponse.result}');
} catch (e) {
  print('Error approving EVM delegation: $e');
}
Each delegation response includes a metadata field with additional details such as chainId, tokenSymbol, tokenAddress, and delegateAddress. Access it via response.metadata?.chainId for approve/revoke, or response.metadata.chainId for transferFrom.

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Solana Approval

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  // Approve a delegate to spend USDC on your behalf
  final response = await portal.delegations.approve(
    chain: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1', // Solana Devnet
    token: 'USDC',
    delegateAddress: '7smgSuU5mjP7QY5yWGdaTfgKn8hUWwvQgfvgcZB3HmJi',
    amount: '0.01',
  );

  // Sign and send the transaction
  final encodedTx = response.encodedTransactions!.first!;
  final txResponse = await portal.request(
    chainId: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1',
    method: 'sol_signAndSendTransaction',
    params: [encodedTx],
  );
  print('Tx hash: ${txResponse.result}');
} catch (e) {
  print('Error approving Solana delegation: $e');
}

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Checking Delegation Status

Use getStatus to check current delegations and token balances for a specific delegate address.

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EVM Status Check

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  final response = await portal.delegations.getStatus(
    chain: 'eip155:11155111',
    token: 'USDC',
    delegateAddress: '0xa944e86eb36f039becd1843132347eb5b8501562',
  );

  print('Chain ID: ${response.chainId}');
  print('Token: ${response.token}');
  print('Token Address: ${response.tokenAddress}');
  if (response.balance != null) print('Balance: ${response.balance}');
  if (response.balanceRaw != null) print('Balance Raw: ${response.balanceRaw}');
  print('Delegations: ${response.delegations.length}');

  for (final delegation in response.delegations) {
    print('  - Address: ${delegation!.address}, Amount: ${delegation.delegateAmount} (Raw: ${delegation.delegateAmountRaw})');
  }
} catch (e) {
  print('Error getting EVM delegation status: $e');
}

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Solana Status Check

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  final response = await portal.delegations.getStatus(
    chain: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1',
    token: 'USDC',
    delegateAddress: '7smgSuU5mjP7QY5yWGdaTfgKn8hUWwvQgfvgcZB3HmJi',
  );

  print('Chain ID: ${response.chainId}');
  print('Token: ${response.token}');
  if (response.tokenAccount != null) print('Token Account: ${response.tokenAccount}');
  print('Delegations: ${response.delegations.length}');

  for (final delegation in response.delegations) {
    print('  - Address: ${delegation!.address}, Amount: ${delegation.delegateAmount} (Raw: ${delegation.delegateAmountRaw})');
  }
} catch (e) {
  print('Error getting Solana delegation status: $e');
}

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Revoking Delegations

Use revoke to remove spending permissions from a delegate address.

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EVM Revoke

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  final response = await portal.delegations.revoke(
    chain: 'eip155:11155111',
    token: 'USDC',
    delegateAddress: '0xa944e86eb36f039becd1843132347eb5b8501562',
  );

  // Sign and send the transaction
  final tx = response.transactions!.first!;
  final txResponse = await portal.request(
    chainId: 'eip155:11155111',
    method: 'eth_sendTransaction',
    params: [
      {'from': tx.from, 'to': tx.to, 'data': tx.data, 'value': tx.value}
    ],
  );
  print('Tx hash: ${txResponse.result}');
} catch (e) {
  print('Error revoking EVM delegation: $e');
}

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Solana Revoke

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  final response = await portal.delegations.revoke(
    chain: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1',
    token: 'USDC',
    delegateAddress: '7smgSuU5mjP7QY5yWGdaTfgKn8hUWwvQgfvgcZB3HmJi',
  );

  // Sign and send the transaction
  final encodedTx = response.encodedTransactions!.first!;
  final txResponse = await portal.request(
    chainId: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1',
    method: 'sol_signAndSendTransaction',
    params: [encodedTx],
  );
  print('Tx hash: ${txResponse.result}');
} catch (e) {
  print('Error revoking Solana delegation: $e');
}
Always revoke unused delegations after completing operations to minimize security risks.

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Transferring as a Delegate

Use transferFrom to transfer tokens from another address that has delegated spending permission to you.

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EVM Transfer From

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  final response = await portal.delegations.transferFrom(
    chain: 'eip155:11155111',
    token: 'USDC',
    fromAddress: '0x099699ed181517d4ce0ba4487bea671d31bb1db5', // Token owner
    toAddress: '0xdFd8302f44727A6348F702fF7B594f127dE3A902',   // Recipient
    amount: '0.01',
  );

  // Sign and send the transaction
  final tx = response.transactions!.first!;
  final txResponse = await portal.request(
    chainId: 'eip155:11155111',
    method: 'eth_sendTransaction',
    params: [
      {'from': tx.from, 'to': tx.to, 'data': tx.data, 'value': tx.value}
    ],
  );
  print('Tx hash: ${txResponse.result}');
} catch (e) {
  print('Error transferring EVM delegation: $e');
}

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Solana Transfer From

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  final response = await portal.delegations.transferFrom(
    chain: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1',
    token: 'USDC',
    fromAddress: 'ARttPLesu9RiX6H111Pfdc9Y2DhGy1B8P8jyyrD8Cj5b', // Token owner
    toAddress: 'GPsPXxoQA51aTJJkNHtFDFYui5hN5UxcFPnheJEHa5Du',   // Recipient
    amount: '0.01',
  );

  // Sign and send the transaction
  final encodedTx = response.encodedTransactions!.first!;
  final txResponse = await portal.request(
    chainId: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1',
    method: 'sol_signAndSendTransaction',
    params: [encodedTx],
  );
  print('Tx hash: ${txResponse.result}');
} catch (e) {
  print('Error transferring Solana delegation: $e');
}
Delegation Roles: fromAddress is the token owner who approved the delegation. Your wallet (the delegate) signs the transaction to transfer tokens from the owner to the toAddress recipient.

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Supported Networks

Delegations work on all Portal-supported EVM and Solana chains:
  • EVM: Ethereum, Polygon, Base, Arbitrum, Optimism, and all other EVM-compatible chains
  • Solana: Solana Mainnet and Devnet
For a complete list, see Blockchain Support.

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Next Steps