Manage Token Delegations

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.

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

Prerequisites

Before using delegation operations, ensure you have:

A properly initialized Portal client
An active wallet with tokens on the target network (see Create a wallet)
Understanding of token delegations concepts

Delegations apply to ERC-20 tokens (EVM) and SPL Tokens (Solana) only. Native assets like ETH, MON, and SOL cannot be delegated — they have no on-chain approve / transferFrom (or SPL delegate) semantics. Calls using a native asset identifier will be rejected. See Delegations for the protocol-level reason and workarounds.

All examples below assume Portal has already been initialized with await portal.initialize(apiKey: 'YOUR_API_KEY'). See Getting Started for details.

High-Level Methods

Use approveAndSubmit, revokeAndSubmit, and transferAndSubmit when you want one call for the whole flow: build the delegation transaction(s), then sign and broadcast each one in order and collect the resulting hashes. The wallet’s signer is wired up for you, and EVM and Solana chains are routed to the right RPC method automatically, so the common case needs no configuration at all.

approveAndSubmit, revokeAndSubmit, and transferAndSubmit broadcast each transaction and return as soon as it is accepted by the network. They do not wait for on-chain confirmation. A returned hash means the transaction was submitted, not that it succeeded — an approval can still revert. If your flow depends on the delegation being active, wait for the receipt yourself, or poll getStatus before proceeding.

Signatures

Future<List<String>> approveAndSubmit({
  required String chain,
  required String token,
  required String delegateAddress,
  required String amount,
  void Function(DelegationSubmitProgress)? onProgress,
});

Future<List<String>> revokeAndSubmit({
  required String chain,
  required String token,
  required String delegateAddress,
  void Function(DelegationSubmitProgress)? onProgress,
});

Future<List<String>> transferAndSubmit({
  required String chain,
  required String token,
  required String fromAddress,
  required String toAddress,
  required String amount,
  void Function(DelegationSubmitProgress)? onProgress,
});

Each takes the same parameters as its low-level counterpart — see EVM Approval, EVM Revoke, and EVM Transfer From below — plus an optional onProgress. Failures throw a PortalException, so wrap calls in try / catch.

Progress

onProgress is optional. When set, it is called twice per transaction — once with signing before signing begins, and once with submitted after the transaction is broadcast. For a batch of n transactions it is called 2n times. DelegationSubmitProgress carries:

Field	Type	Description
`step`	`DelegationSubmitStep`	`signing` or `submitted`.
`index`	`int`	The 0-based index of this transaction in the sequence.
`total`	`int`	The total number of transactions in the sequence.
`hash`	`String?`	`null` on `signing`, and the broadcast transaction hash on `submitted`.

DelegationSubmitStep has exactly two values — signing and submitted. There is no confirming or confirmed step, because nothing is awaited on-chain.

Return value

All three return List<String> — one transaction hash per broadcast transaction, in submission order. Most delegation flows produce a single transaction, so the list usually has one element. Transactions are submitted sequentially, not batched into one RPC call: if the API returns multiple payloads, the second is only sent after the first has been broadcast. There is no status field and no partial-success concept: a hash is present because the network accepted the transaction, and nothing beyond that has been checked.

Example (approve and submit)

import 'package:portal_flutter/portal_flutter.dart';

final portal = Portal();

try {
  final hashes = await portal.delegations.approveAndSubmit(
    chain: 'eip155:11155111', // Sepolia testnet
    token: 'USDC',
    delegateAddress: '0xa944e86eb36f039becd1843132347eb5b8501562',
    amount: '0.01',
    onProgress: (progress) {
      print('${progress.step.value} ${progress.index + 1}/${progress.total}');
    },
  );

  print('Approved. Hashes: $hashes');
} on PortalException catch (e) {
  print('approveAndSubmit failed: ${e.message}');
}

Example (revoke and submit)

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

  print('Revoked. Hashes: $hashes');
} on PortalException catch (e) {
  print('revokeAndSubmit failed: ${e.message}');
}

Example (transfer as a delegate)

The wallet calling transferAndSubmit must already be an approved delegate of fromAddress.

try {
  final hashes = await portal.delegations.transferAndSubmit(
    chain: 'eip155:11155111',
    token: 'USDC',
    fromAddress: '0xowner...',     // the wallet that approved the delegation
    toAddress: '0xrecipient...',
    amount: '0.01',
  );

  print('Transferred. Hashes: $hashes');
} on PortalException catch (e) {
  print('transferAndSubmit failed: ${e.message}');
}

Example (Solana)

The same three methods work on Solana — pass a solana: CAIP-2 chain ID and the SDK signs and submits via sol_signAndSendTransaction instead of eth_sendTransaction:

final hashes = await portal.delegations.approveAndSubmit(
  chain: 'solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1', // Solana devnet
  token: 'USDC',
  delegateAddress: 'DELEGATE_SOLANA_ADDRESS',
  amount: '0.01',
);

Errors

All failures throw a PortalException. Catch it with on PortalException:

Code	When
`NOT_INITIALIZED`	`portal.initialize()` has not completed yet.
`DELEGATION_APPROVE_AND_SUBMIT_ERROR`	`approveAndSubmit` failed while building, signing, or broadcasting.
`DELEGATION_REVOKE_AND_SUBMIT_ERROR`	`revokeAndSubmit` failed while building, signing, or broadcasting.
`DELEGATION_TRANSFER_AND_SUBMIT_ERROR`	`transferAndSubmit` failed while building, signing, or broadcasting.

The message carries the underlying reason. Two come from the native SDK itself:

Message	When
`No transactions in delegation response.`	The API returned no transactions to sign, so there is nothing to submit.
`Invalid transaction hash returned from signAndSendTransaction at index N for chain C.`	A transaction was signed but no usable hash came back. The message names which transaction in the sequence it was.

Most failures instead surface the API’s own error message, such as:

Message	When
`USDC token account does not exist.`	Revoking or transferring for a token the wallet has never held. `approve` does not raise this — it adds a token-account creation instruction to the transaction it returns.
`No active delegation to revoke`	`revoke` when the token account has no delegate set.
`No delegation active`	`transferFrom` when the owner has not approved a delegation.
`Authenticated client is not the delegate`	`transferFrom` from a wallet other than the approved delegate.
`Transfer amount exceeds delegated amount`	`transferFrom` for more than the approved allowance.
`Owner has insufficient USDC balance`	`transferFrom` for more than the owner actually holds. `approve` does not check balance — you may approve more than you hold.
`Delegation is only supported on Solana mainnet and devnet`	A `solana:` chain ID other than mainnet or devnet.

The submit methods can also fail with the same network and decoding errors the low-level methods return.

try {
  final hashes = await portal.delegations.approveAndSubmit(
    chain: 'eip155:11155111',
    token: 'USDC',
    delegateAddress: '0x1a3eda7eb7d13e60e638711c580490c19e164fee',
    amount: '0.01',
  );
  print('Submitted hashes: $hashes');
} on PortalException catch (e) {
  print('approveAndSubmit failed (${e.code}): ${e.message}');
}

Low-level methods

The sections below are the manual path: approve, revoke, transferFrom, and getStatus return unsigned transactions and leave signing and broadcasting to you. You receive EVM transaction objects or Solana-encoded payloads and call portal.request with the right method (eth_sendTransaction or sol_signAndSendTransaction) yourself. Use them when you need to inspect, modify, batch, or route the transactions yourself. Otherwise prefer the high-level methods above.

Approving Delegations

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

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.

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');
}

Checking Delegation Status

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

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');
}

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');
}

Revoking Delegations

Use revoke to remove spending permissions from a delegate address.

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');
}

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.

Transferring as a Delegate

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

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');
}

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.

Supported Networks

Delegations work on all Portal-supported EVM and Solana chains:

EVM: Ethereum, Polygon, Base, Arbitrum, Optimism, Monad, and all other EVM-compatible chains
Solana: Solana Mainnet and Devnet

For a complete list, see Blockchain Support.

Getting Started

SDKs

APIs

Integrations

Resources

Manage Token Delegations

Overview

Prerequisites

High-Level Methods

Signatures

Progress

Return value

Example (approve and submit)

Example (revoke and submit)

Example (transfer as a delegate)

Example (Solana)

Errors

Low-level methods

Approving Delegations

EVM Approval

Solana Approval

Checking Delegation Status

EVM Status Check

Solana Status Check

Revoking Delegations

EVM Revoke

Solana Revoke

Transferring as a Delegate

EVM Transfer From

Solana Transfer From

Supported Networks

Next Steps

​Overview

​Prerequisites

​High-Level Methods

​Signatures

​Progress

​Return value

​Example (approve and submit)

​Example (revoke and submit)

​Example (transfer as a delegate)

​Example (Solana)

​Errors

​Low-level methods

​Approving Delegations

​EVM Approval

​Solana Approval

​Checking Delegation Status

​EVM Status Check

​Solana Status Check

​Revoking Delegations

​EVM Revoke

​Solana Revoke

​Transferring as a Delegate

​EVM Transfer From

​Solana Transfer From

​Supported Networks

​Next Steps

Overview

Prerequisites

High-Level Methods

Signatures

Progress

Return value

Example (approve and submit)

Example (revoke and submit)

Example (transfer as a delegate)

Example (Solana)

Errors

Low-level methods

Approving Delegations

EVM Approval

Solana Approval

Checking Delegation Status

EVM Status Check

Solana Status Check

Revoking Delegations

EVM Revoke

Solana Revoke

Transferring as a Delegate

EVM Transfer From

Solana Transfer From

Supported Networks

Next Steps