Butterfly — A cross-platform, open-source note-taking app for drawing, writing, and organizing ideas visually.
Analyzed by Sai Pavan Gopularam · Productivity · Notes · View on GitHub
- Stars: 2012
- Forks: 147
- Commits last 30 days: 84
- Health: Active (84 commits this month)
- Language: Dart
- License: AGPL-3.0
What It Is
Butterfly is a powerful, minimalistic, open-source note-taking application that lets you combine text, drawings, and images on an infinite canvas. Think of it like a digital whiteboard or an infinite sketchbook that works across all your devices—Android, Windows, Linux, and web—allowing you to sketch ideas, jot down thoughts, and organize visual information.
This app matters because it offers a flexible, visual way to capture ideas, moving beyond linear text. It solves the problem of platform lock-in and limited canvas space, giving users freedom over their data and how they express their thoughts across various devices, from a phone to a desktop with a stylus.
License Verdict
AGPL-3.0 — Strong Copyleft, SaaS Restrictions — Commercial Use Complex • Requires Source Disclosure for Network Services
The AGPL-3.0 license means if you modify this software and offer it as a network service (like a SaaS), you must make the complete source code of your modified version available to all users of that service. You can distribute modified versions, but they must also be under AGPL-3.0. This significantly restricts building proprietary SaaS products directly on top of Butterfly, though the `api` directory is Apache-2.0 licensed, allowing more flexibility for extensions.
How to Use It
To get Butterfly running locally for development, you'll need the Flutter SDK installed. Clone the repository, navigate into the directory, fetch dependencies, and then run the application. The primary README focuses on end-user downloads, so developer build steps are inferred.
Prerequisites:
- Flutter SDK
- Dart SDK
Estimated setup time: 30 minutes.
git clone https://github.com/LinwoodDev/Butterfly.git
cd Butterfly
flutter pub get
flutter runWhat I'd Build With This
Butterfly Asset Marketplace (micro-saas)
Build a dedicated online marketplace where Butterfly users can buy and sell custom digital assets like unique brushes, shape packs, paper textures, and specialized note templates. You'd earn a commission on each sale. This product targets digital artists, students, and visual thinkers who want to enhance their note-taking experience with unique styles and tools.
Effort: 1 Week Build Time · Target: Digital Artists, Students, Visual Thinkers · Pricing: 15-30% commission on sales
Specialized Butterfly for Visual Brainstorming Teams (saas)
Offer a service that provides customized, self-hosted deployments of Butterfly for design teams or agile software teams. You would bundle Butterfly with enhanced collaboration features (e.g., integrated shared WebDAV storage, version control for notes) and charge for the setup, ongoing support, and maintenance. All modifications to Butterfly would remain AGPL and accessible to the client, but the service value is in deployment and management.
Effort: 2 Months Build Time · Target: Design Teams, Agile Software Teams · Pricing: $299/month per team
White-Label Visual Documentation Suite (enterprise)
Provide a comprehensive service for large organizations (e.g., engineering firms, educational institutions) to deploy a fully branded and customized version of Butterfly as their internal visual documentation and knowledge-sharing tool. This includes custom integrations with their existing IT infrastructure (SSO, internal storage solutions) and ongoing maintenance. The enterprise pays for your expertise, branding, and integration services, not the AGPL software itself.
Effort: 3 Months Build Time · Target: Large Enterprises, Universities · Pricing: $5,000 - $20,000 per project + annual support
Sai Pavan Gopularam's Take
Butterfly is a solid, feature-rich note-taking app, but the AGPL-3.0 license is a huge hurdle for traditional SaaS. You can't just host it and charge subscriptions without open-sourcing your changes. However, there's a good business in selling assets like templates or offering custom deployment services; a marketplace for Butterfly assets could easily pull in $500/month in commissions.
Watch Out For
- AGPL-3.0 License Restrictions: The core application's AGPL-3.0 license means any modifications you make and offer as a network service must have their source code disclosed to users. This severely limits proprietary SaaS business models.
- Flutter Development Overhead: Building and maintaining a Flutter application requires familiarity with Dart and the Flutter ecosystem, which can have its own learning curve and platform-specific quirks for cross-platform deployment.
- Data Storage Configuration: Users can choose local or WebDAV storage. For any team-based or cloud-synced solutions, managing and guiding users through WebDAV setup or providing a robust alternative will be a key challenge.
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