S3 Dart

An S3 Dart Client SDK that provides simple APIs to access any Amazon S3 compatible object storage server. Optimized for Wasabi S3 but fully compatible with AWS S3, MinIO, Filebase, and any other S3-compatible provider.

Features

• Custom endpoint support — returns your supplied endpoint directly, no hardcoded AWS region overrides
• Smart region detection — skips the getBucketRegion API call when the region is already present in the endpoint URL
• File operations for all providers — fPutObject / fGetObject work correctly with any S3-compatible endpoint, not just AWS
• Presigned DELETE — presignedDeleteObject convenience method for generating signed delete URLs
• Region fallback — gracefully falls back to us-east-1 or the configured region instead of failing with an empty string

API

Bucket operations	Object operations	Presigned operations	Bucket Policy & Notification operations
makeBucket	getObject	presignedUrl	getBucketNotification
listBuckets	getPartialObject	presignedGetObject	setBucketNotification
bucketExists	fGetObject	presignedPutObject	removeAllBucketNotification
removeBucket	putObject	presignedDeleteObject	listenBucketNotification
listObjects	fPutObject	presignedPostPolicy	getBucketPolicy
listObjectsV2	copyObject		setBucketPolicy
listIncompleteUploads	statObject
listAllObjects	removeObject
listAllObjectsV2	removeObjects
	removeIncompleteUpload

Usage

Initialize S3 Client

Wasabi S3

Wasabi S3 uses regional endpoints. Specify the endpoint that matches your bucket's region:

// US East 1 (default)
final minio = Minio(
  endPoint: 's3.wasabisys.com',
  accessKey: 'YOUR-ACCESSKEYID',
  secretKey: 'YOUR-SECRETACCESSKEY',
  region: 'us-east-1',
);

// US East 2
final minio = Minio(
  endPoint: 's3.us-east-2.wasabisys.com',
  accessKey: 'YOUR-ACCESSKEYID',
  secretKey: 'YOUR-SECRETACCESSKEY',
  region: 'us-east-2',
);

// US West 1
final minio = Minio(
  endPoint: 's3.us-west-1.wasabisys.com',
  accessKey: 'YOUR-ACCESSKEYID',
  secretKey: 'YOUR-SECRETACCESSKEY',
  region: 'us-west-1',
);

// EU Central 1
final minio = Minio(
  endPoint: 's3.eu-central-1.wasabisys.com',
  accessKey: 'YOUR-ACCESSKEYID',
  secretKey: 'YOUR-SECRETACCESSKEY',
  region: 'eu-central-1',
);

// AP Southeast 2 (Sydney)
final minio = Minio(
  endPoint: 's3.ap-southeast-2.wasabisys.com',
  accessKey: 'YOUR-ACCESSKEYID',
  secretKey: 'YOUR-SECRETACCESSKEY',
  region: 'ap-southeast-2',
);

All Wasabi regional endpoints follow the pattern s3.<region>.wasabisys.com. See Wasabi service endpoints for the full list.

---

AWS S3

final minio = Minio(
  endPoint: 's3.amazonaws.com',
  accessKey: 'YOUR-ACCESSKEYID',
  secretKey: 'YOUR-SECRETACCESSKEY',
);

MinIO

final minio = Minio(
  endPoint: 'play.min.io',
  accessKey: 'Q3AM3UQ867SPQQA43P2F',
  secretKey: 'zuf+tfteSlswRu7BJ86wekitnifILbZam1KYY3TG',
);

Filebase

final minio = Minio(
  endPoint: 's3.filebase.com',
  accessKey: 'YOUR-ACCESSKEYID',
  secretKey: 'YOUR-SECRETACCESSKEY',
  useSSL: true,
);

---

File upload

import 'package:s3_dart/io.dart';
import 'package:s3_dart/minio.dart';

void main() async {
  final minio = Minio(
    endPoint: 's3.wasabisys.com',
    accessKey: 'YOUR-ACCESSKEYID',
    secretKey: 'YOUR-SECRETACCESSKEY',
  );

  await minio.fPutObject('mybucket', 'myobject', 'path/to/file');
}

To use fPutObject() and fGetObject(), you must import 'package:s3_dart/io.dart';

For a complete example, see the example/ directory.

Upload with progress

import 'package:s3_dart/minio.dart';

void main() async {
  final minio = Minio(
    endPoint: 's3.wasabisys.com',
    accessKey: 'YOUR-ACCESSKEYID',
    secretKey: 'YOUR-SECRETACCESSKEY',
  );

  await minio.putObject(
    'mybucket',
    'myobject',
    Stream<Uint8List>.value(Uint8List(1024)),
    onProgress: (bytes) => print('$bytes uploaded'),
  );
}

Get object

import 'dart:io';
import 'package:s3_dart/minio.dart';

void main() async {
  final minio = Minio(
    endPoint: 's3.wasabisys.com',
    accessKey: 'YOUR-ACCESSKEYID',
    secretKey: 'YOUR-SECRETACCESSKEY',
  );

  final stream = await minio.getObject('mybucket', 'myobject');

  // Get object length
  print(stream.contentLength);

  // Write object data to file
  await stream.pipe(File('output.txt').openWrite());
}

---

Presigned URLs

Presigned URLs allow clients to perform S3 operations directly — without exposing credentials. This SDK supports presigned GET, PUT, DELETE, and HEAD via both named convenience methods and the generic presignedUrl.

Presigned GET (download)

final url = await minio.presignedGetObject(
  'mybucket',
  'myobject',
  expires: 3600, // 1 hour
);
// Share this URL — anyone can download the object until it expires

Presigned PUT (upload)

final url = await minio.presignedPutObject(
  'mybucket',
  'myobject',
  expires: 900, // 15 minutes
);
// The client can PUT directly to this URL without credentials

Presigned DELETE (remove object)

final url = await minio.presignedDeleteObject(
  'mybucket',
  'myobject',
  expires: 900, // 15 minutes
);
// Send an HTTP DELETE request to this URL to remove the object

Generic presigned URL

Use presignedUrl for any HTTP method (GET, PUT, DELETE, HEAD):

final url = await minio.presignedUrl(
  'DELETE',
  'mybucket',
  'myobject',
  expires: 900,
);

Presigned POST policy (browser upload)

For browser uploads with policy restrictions on name, content-type, size, and expiry:

final policy = PostPolicy()
  ..setBucket('mybucket')
  ..setKey('myobject')
  ..setExpires(DateTime.now().add(Duration(minutes: 15)));

final formData = await minio.presignedPostPolicy(policy);

---

Features and bugs

Please file feature requests and bugs at the issue tracker.

Contributions are welcome.

License

MIT

Libraries

io

minio

models

s3_dart