Beyond a Figma Clone: Building Real-Time Collaborative Apps with Flutter and Supabase
Real-time collaboration is no longer a “nice to have.” From design tools to education platforms, users increasingly expect to see each other’s cursors, edits, and actions live. While products like Figma popularized this experience, the underlying methodology is far more general—and reusable—than it may appear at first glance.
In this article, we’ll explore how the Flutter + Supabase real-time canvas methodology can be extended beyond a Figma clone to power an entire class of collaborative applications.
The Core Methodology
At its heart, this approach combines three ideas:
Local-first rendering
Shared authoritative state
Presence and intent signaling
Instead of sending pixels or frames over the network, each client renders everything locally. The network is used only to synchronize intent—for example, “a rectangle was created,” “this shape moved,” or “this cursor is here.”
Flutter’s CustomPainter handles high-performance rendering on the client, while Supabase Realtime Broadcast distributes small, structured state updates to all connected users.
Why This Scales Beyond Design Tools
What makes this methodology powerful is that it is domain-agnostic. Once you abstract your state into synchronized objects (often called something like SyncObject), you can reuse the same architecture across many problem spaces.
The key is to think in terms of:
Objects, not screens
Events, not snapshots
Local prediction, not remote control
This unlocks a surprising range of applications.
Apps You Can Build with the Same Architecture
1. Collaborative Whiteboards
Whiteboards are the most direct extension of a Figma-style canvas:
Freehand drawing
Sticky notes
Shapes and connectors
Live cursors and selections
Because drawing strokes and objects are discrete events, they synchronize efficiently and feel instantaneous to users.
2. Diagram and Flowchart Editors
Flowcharts, architecture diagrams, and UML-style tools fit naturally:
Nodes map to synchronized objects
Connections are derived relationships
Updates are low-frequency but high-value
This makes them cheaper to run in real time than freehand drawing tools.
3. Node-Based Editors
Think of:
Workflow builders
Automation pipelines
Shader graphs
AI prompt graphs
Each node is a stateful object, each edge a reference. The canvas remains the same; only the semantics change.
4. Kanban and Planning Boards
A Kanban board is essentially a constrained canvas:
Cards are draggable objects
Columns are layout rules
Presence shows who is working where
The same cursor-sharing and object-sync logic applies with minimal changes.
5. Educational & Teaching Tools
Live teaching benefits enormously from shared visual context:
Math and physics whiteboards
Algorithm visualizers
Collaborative problem solving
In these scenarios, one user often “leads” while others observe, which further reduces synchronization costs.
6. Creative Tools
With a timeline added, the canvas becomes:
A music sequencer
An animation editor
A simplified video timeline
Playback remains local; only edits are synchronized.
The Real Insight: You’re Building a Platform, Not an App
Once implemented correctly, most of the hard problems are already solved:
Cursor presence
Object identity
Conflict avoidance
Throttling and batching updates
From there, new apps become configurations of the same system, not new systems entirely.
In practice, teams report that 80–90% of the code can be reused across different collaborative tools built on this model.
Cost and Performance Considerations
A common concern with real-time systems is cost. Broadcasting cursor positions dozens of times per second can be expensive if done naively. Best practices include:
Throttling cursor updates
Separating “presence” channels from “state” channels
Broadcasting only deltas, never full state
Making most interactions local-only unless collaboration is required
When applied thoughtfully, this model scales far better than many expect.
STEP BY STEP GUIDE
Real-time collaboration is no longer a “nice to have.” From design tools to education platforms, users increasingly expect to see each other’s cursors, edits, and actions live. While products like Figma popularized this experience, the underlying methodology is far more general—and reusable—than it may appear at first glance.
In this article, we’ll explore how the Flutter + Supabase real-time canvas methodology can be extended beyond a Figma clone to power an entire class of collaborative applications.
The Core Methodology
At its heart, this approach combines three ideas:
Local-first rendering
Shared authoritative state
Presence and intent signaling
Instead of sending pixels or frames over the network, each client renders everything locally. The network is used only to synchronize intent—for example, “a rectangle was created,” “this shape moved,” or “this cursor is here.”
Flutter’s CustomPainter handles high-performance rendering on the client, while Supabase Realtime Broadcast distributes small, structured state updates to all connected users.
Why This Scales Beyond Design Tools
What makes this methodology powerful is that it is domain-agnostic. Once you abstract your state into synchronized objects (often called something like SyncObject), you can reuse the same architecture across many problem spaces.
The key is to think in terms of:
Objects, not screens
Events, not snapshots
Local prediction, not remote control
This unlocks a surprising range of applications.
Apps You Can Build with the Same Architecture
1. Collaborative Whiteboards
Whiteboards are the most direct extension of a Figma-style canvas:
Freehand drawing
Sticky notes
Shapes and connectors
Live cursors and selections
Because drawing strokes and objects are discrete events, they synchronize efficiently and feel instantaneous to users.
2. Diagram and Flowchart Editors
Flowcharts, architecture diagrams, and UML-style tools fit naturally:
Nodes map to synchronized objects
Connections are derived relationships
Updates are low-frequency but high-value
This makes them cheaper to run in real time than freehand drawing tools.
3. Node-Based Editors
Think of:
Workflow builders
Automation pipelines
Shader graphs
AI prompt graphs
Each node is a stateful object, each edge a reference. The canvas remains the same; only the semantics change.
4. Kanban and Planning Boards
A Kanban board is essentially a constrained canvas:
Cards are draggable objects
Columns are layout rules
Presence shows who is working where
The same cursor-sharing and object-sync logic applies with minimal changes.
5. Educational & Teaching Tools
Live teaching benefits enormously from shared visual context:
Math and physics whiteboards
Algorithm visualizers
Collaborative problem solving
In these scenarios, one user often “leads” while others observe, which further reduces synchronization costs.
6. Creative Tools
With a timeline added, the canvas becomes:
A music sequencer
An animation editor
A simplified video timeline
Playback remains local; only edits are synchronized.
The Real Insight: You’re Building a Platform, Not an App
Once implemented correctly, most of the hard problems are already solved:
Cursor presence
Object identity
Conflict avoidance
Throttling and batching updates
From there, new apps become configurations of the same system, not new systems entirely.
In practice, teams report that 80–90% of the code can be reused across different collaborative tools built on this model.
Cost and Performance Considerations
A common concern with real-time systems is cost. Broadcasting cursor positions dozens of times per second can be expensive if done naively. Best practices include:
Throttling cursor updates
Separating “presence” channels from “state” channels
Broadcasting only deltas, never full state
Making most interactions local-only unless collaboration is required
When applied thoughtfully, this model scales far better than many expect.
Conclusion
The Flutter + Supabase real-time canvas approach is not “how to build a Figma clone.” It is a general pattern for collaborative software.
Whether you’re building design tools, educational platforms, planning software, or entirely new creative products, the same principles apply:
Local-first UI, shared intent, and real-time presence.
Once you internalize that, the question stops being “What app should I build?” and becomes “Which domain should I apply this to next?”
Want me to tailor this article for a specific audience (startup founders, Flutter devs, or product engineers)? Or rewrite it as a more technical deep dive with code snippets?
Note: the attached transcript available in this session is for a YouTube advertisement rather than the main video content, so the article is based on the visible video context and methodology rather than the ad itself.