Flutter Engineer

Anythink; United States; Remote; USD 90,000 - 150,000; Part time

Job summary

Anythink is seeking a contract backend engineer to create a Flutter SDK that is easy to use from Dart/Flutter apps. You will build and publish an idiomatic Dart SDK on pub.dev, covering authentication, file storage, and REST API access.

The role includes creating mobile-focused documentation and example applications, plus assisting customer integrations with Flutter. Requirements include production Flutter and Dart experience and publishing a Dart package to pub.dev.

Qualifications

• Production Flutter and Dart experience with apps released to App Store or Google Play.
• Experience integrating REST APIs from Flutter using http or Dio.
• Strong understanding of JSON serialization and asynchronous Dart patterns (Futures/Streams).
• Experience with iOS/Android deployment, provisioning, signing, release builds, and automated signing tools such as Fastlane.
• Experience publishing or maintaining a Dart package on pub.dev.

Responsibilities

• Develop and maintain a Flutter SDK package that wraps platform REST APIs.
• Implement authentication helpers for JWT handling, session refresh, and OAuth flows.
• Provide Flutter support for file uploads, downloads, and storage management.
• Build realistic example applications demonstrating common integration patterns.
• Write setup guides and documentation for mobile developers.
• Contribute to customer projects that integrate the platform with Flutter applications.

Skills

Flutter & Dart

REST APIs

JSON serialization

Futures & Streams

iOS/Android deployment

fastlane

Tools

pub.dev

http

Dio

fastlane

Job description

Role overview

Contract role focused on making a backend platform straightforward to use from Flutter applications. You will build and maintain an idiomatic Dart SDK published through pub.dev, covering authentication, file storage, and REST API access. The work also includes example applications, mobile-focused documentation, and selected customer integration projects.

Responsibilities

• Develop and maintain a Flutter SDK package that wraps platform REST APIs.
• Implement authentication helpers for JWT handling, session refresh, and OAuth flows.
• Provide Flutter support for file uploads, downloads, and storage management.
• Build realistic example applications demonstrating common integration patterns.
• Write setup guides and documentation for mobile developers.
• Contribute to customer projects that integrate the platform with Flutter applications.

Requirements

• Production Flutter and Dart experience with applications released to the App Store or Google Play.
• Experience integrating REST APIs from Flutter using tools such as `http` or `dio`.
• Strong understanding of JSON serialization and asynchronous Dart patterns, including Futures and Streams.
• Experience with iOS and Android deployment, provisioning, signing, release builds, and automated signing tools such as fastlane.
• Experience publishing or maintaining a Dart package on pub.dev.

Nice to have

• Experience using platform channels to connect Flutter with native iOS or Android code.
• Familiarity with Riverpod, Bloc, or another state-management approach.
• WebSocket integration experience.
• Previous Firebase experience.
• Experience designing SDK packages for developer ergonomics.