Add and manage OAuth2 authentication for your Chopper client


Offers a oauth_chopper client to help manage your OAuth2 authentication with Choppper. The oauth_chopper client uses oauth2 package from the dart team and combines this with Chopper. It offers a Chopper Authenticator and HeaderInterceptor to manage the OAuth2 authorizations.

By default it doesn't persist any credential information. It uses an in memory storage by default. This can be override by providing a custom storage implementation.

Currently it supports the following grants:

  • ✅ ResourceOwnerPasswordGrant
  • ✅ ClientCredentialsGrant
  • ✅ AuthorizationCodeGrant


Create a oauth_chopper client with the needed authorizationEndpoint, identifier and secret.
Add the oauth_chopper_authenticator + oauth_chopper_interceptor to your chopper client.
Request a OAuthGrant on the oauth_chopper client.


  /// Create OAuthChopper instance.
  final oauthChopper = OAuthChopper(
    authorizationEndpoint: authorizationEndpoint,
    identifier: identifier,
    secret: secret,

  /// Add the oauth authenticator and interceptor to the chopper client.
  final chopperClient = ChopperClient(
    baseUrl: Uri.parse(''),
    authenticator: oauthChopper.authenticator(),
    interceptors: [

  /// Request grant
      username: 'username',
      password: 'password',

// Authorization Cod eGrant
  oauth_chopper.AuthorizationCodeGrant grant = oauth_chopper.AuthorizationCodeGrant(
    tokenEndpoint: Uri.parse("tokenEndpoint"),
    scopes: ["scope1", "scope2"],
    redirectUrl: Uri.parse("redirectUrl"),
    redirect: redirect,
    listen: listen,

If you want to persist the OAuth2 credential information you can provide a custom OAuthStorage implementation for example with flutter_secure_storage:

const _storageKey = 'storage_key';  
class OAuthCredentialsStorage implements OAuthStorage {    
  final FlutterSecureStorage _storage;    
 const OAuthCredentialsStorage(this._storage);    
  FutureOr<void> clear() async {    
    await _storage.delete(key: _storageKey);    
  FutureOr<String?> fetchCredentials() async {    
    final credentialsJson = await _storageKey);    
 return credentialsJson;    
  FutureOr<void> saveCredentials(String? credentialsJson) async {    
    await _storage.write(key: _storageKey, value: credentialsJson);    
} }  

Additional information

Feel free to give me any feedback to improve this package.


OAuthChopper for configuring OAuth authentication with Chopper.