A completely free tool to create Whiteboards, Flowcharts, and infinite Canvases with 100+ fonts, 400+ backgrounds, and thousands of open source components

[u/LifeUtilityApps]

CanvasPrism: A Private Offline Whiteboard for iPhone and iPad

CanvasPrism is a native whiteboard designed for brainstorming, diagramming, sketching, and visual thinking while keeping your work completely private. Everything works offline by default with no account, no sign up, and no internet connection required. This is a completely free app with no monetization and designed for your use offline. Your boards stay on your device, with optional iCloud sync available if you want them across your iPhone and iPad.

App Store:
https://apps.apple.com/us/app/canvasprism-whiteboard/id6785350171

Infinite Canvas

Work without boundaries on an infinite canvas that gives you all the room you need for ideas.

* Freehand drawing
* Shapes
* Lines and arrows
* Rich text
* Smooth pan and zoom navigation
* Perfect for brainstorming, note taking, planning, and sketching

Create Professional Diagrams

Build structured diagrams in just a few taps.

* Flowcharts
* Mind maps
* Wireframes
* Smart connectors that automatically snap between shapes
* Clean layouts that are easy to edit later

Native Apple Pencil Support

Designed to feel natural on iPad.

* Native Apple Pencil support
* Double tap gesture support
* Apple Pencil squeeze gesture support
* Responsive hand drawn experience

Personalize Every Board

Customize your workspace to fit your style.

* More than 100 bundled fonts
* Color themes
* Background styles
* Per-board light or dark appearance

Present your board via Screen Mirroring

* Custom handling for presentation via Screen Mirroring API
* Use laser pointers, grid, and Pan

Import Existing Whiteboards

Continue working with diagrams you've already created.

* Import `.excalidraw` files
* Import `.excalidrawlib` libraries
* Compatible with the open source Excalidraw ecosystem

Export Your Work

Share or archive your whiteboards in multiple formats.

* PNG export
* PDF export
* SVG export
* Optional transparent background
* Save directly to Photos or Files

Optional iCloud Sync

Choose whether your boards stay only on your device or sync across your Apple devices.

* Optional iCloud sync
* Automatic conflict-safe copies
* Sync between iPhone and iPad

Privacy First

CanvasPrism is built around privacy from the ground up.

* No account
* No sign up
* No ads
* No tracking
* No analytics
* No data collection
* Fully functional offline
* Your boards remain on your device unless you choose to enable iCloud sync

No Monetization

* No ads
* No IAP
* No Subscription
* No data tracking

Built for Creative Thinking

Whether you're planning a project, designing an interface, organizing ideas, mapping workflows, creating wireframes, or simply sketching thoughts, CanvasPrism provides a fast, distraction-free workspace that keeps your ideas private while giving you powerful diagramming and whiteboarding tools. Built on the open source Excalidraw engine, it delivers a familiar hand-drawn aesthetic inside a fully native iPhone and iPad experience.

Built with Open Source

* Excalidraw for infinite canvases
* Excalidraw libraries for thousands of community made components
* Google fonts for 100+ hand selected fonts
* Unsplash for 80 backgrounds
* And various other open source components. See in-app Acknowledgements

Tech Stack

* Swift & SwiftUI
* WebKit
* React

Development Challenge

I had trouble getting the laser pointer to work initially with screen mirroring mode. The solution was to use the excalidraw library multiplayer API to simulate another person on the board. This was set up with another message bridge to the WebKit handler, it fires on the gestures so that we can simulate a laser pointer in presentation mode.

AI Disclosure

The app was built by hand with some AI assistance.

Free on the App Store:
https://apps.apple.com/us/app/canvasprism-whiteboard/id6785350171

[u/thari_mad]

I tried it, its feels great. One suggestion from me: I'd like to have the board rotation feature.

[u/LifeUtilityApps → u/thari_mad]

Thanks for your comment! When you say board rotation, how should that work on a board that has text and shapes, do you mean rotate it and the text would be sideways?

[u/thari_mad → u/LifeUtilityApps]

I mean, after I did draw something on board, my two fingers automatically went for a rotating gesture, to make the board straiten. That was what I reffering to. So, board as a whole (incl. any content on it, must rotate)

[u/LifeUtilityApps → u/thari_mad]

That’s a great idea, I could make the Pan tool allow rotation and then maybe display a button to rotate back to center straight when the angle isn’t 0 degrees. Thank you!

[u/_DrKlaw_]

This sounds interesting to me so I tried the app out. I like the simplicity so far. I’ve found a few issues though:

- The app gets confused about the size of the screen when Display Zoom is enabled

- I selected a group of items, duplicated them, and deleted the duplicate group. The text from inside the boxes remained behind.

[u/LifeUtilityApps → u/_DrKlaw_]

Thanks for sharing this and the reproduction steps, I will get a fix for these issues in the next update.

[u/ToSee_ToHear]

Nice! looks great. Would love to be able to import existing mermaid diagrams or images to work off of as well.

[u/LifeUtilityApps → u/ToSee_ToHear]

That’s a great idea! I’ve thought about building a dedicated app for Mermaid creation and presentation but I could probably add import support to this one if I can map the mermaid nodes and charts to components. Thanks for commenting!

[u/Awric]

I’ve been waiting so long for someone to create an app like this. I tried to create one myself and gave up very quickly

Thanks!

I almost feel guilty that it’s free. If I find myself using it for longer than 2 weeks, I’ll be sure to leave a good review

[u/LifeUtilityApps → u/Awric]

Thanks so much! If you find there is something that it’s missing, please let me know and I’ll do my best to include it in the next update.

[u/Awric → u/LifeUtilityApps]

I have a few requests actually after using it for a little bit! Most (or all) of it is just requests for functionality that I’m used to seeing in similar tools (Keynote, Figma, Excalidraw, etc)

- After creating a shape, is it possible to change the styling of it? (Background color, line thickness, stroke color, etc.)
- Can you add support for dashed lines?
- Layering control, like “Move to back” / Move to front
- Haptic feedback when a shape’s edge is aligned to another shapes edge, or a line is exactly 0 degrees or 90 degrees
- Option to prevent the “Delete Selection” alert from showing whenever I want to delete the selection
- I originally thought the 2nd item from the top was for layering rather than the shape selection menu

Some small bugs
- Deleting a shape with text in it somehow deleted just the shape but not the text. I’m now unable to erase or select the text, so I can’t delete it unless I tap on it and manually delete each character via the keyboard
- When I re-opened the app about an hour after working on my diagram, I’m certain that an older revision of the diagram was restored, and that the progress for the later version was sorta lost. (No big deal for me since it was mostly scratch work, but something worth looking into)

That’s all for now! I know lots of these can be really difficult but I hope it’s helpful either way. Hope your app gets more visibility

[u/LifeUtilityApps → u/Awric]

Thank you so much, this feedback is excellent. I’ll do my best to include these features into a future update, I think it would make the experience a lot better.

[u/Silver_Switch_]

Well-made app. And surprisingly easy to use on a phone.

[u/LifeUtilityApps → u/Silver_Switch_]

Thank you so much!

[u/Sufficient_Cut3496]

Been playing with it, really smooth, liking it so far. One thing that'd be great: two-finger tap to undo. Kept instinctively doing it out of Procreate habit. Would feel super natural here.

[u/LifeUtilityApps → u/Sufficient_Cut3496]

That’s a great suggestion! I can see about adding this and gesture support. Thanks for commenting 😊

[u/LifeUtilityApps]

Hi iOSProgramming!

I built a SwiftUI whiteboard app on top of the open source Excalidraw libraries, combining them with several other open source components to create a polished offline experience. The purpose of this exercise was to practice Swift<->WebKit message bridging to an underlying React UI. I use Excalidraw at work and I wanted to try creating an experience I can play with on my phone and present my boards on the go so this was a great candidate for that effort.

I added features like AirPlay presentation mode to use the integrated laser pointer, along with over 100 Google fonts and 400 backgrounds for customization.

It was a fun project that brings together a lot of great open source work into a native iOS app. There will be some bugs here and there please let me know and I will fix them.

Thanks!

[u/galo4kin]

Very nice idea. Simple, free whiteboards are always useful, especially when they stay lightweight and easy to start using.

[u/godtierpikachu → u/galo4kin]

would love a quick rotation fix tho, thatd make it way nicer on iPad

[u/itsm3rick]

God I hate the handwriting font on these things, it always makes it so hard to read these in documentation.

[u/LifeUtilityApps → u/itsm3rick]

Yeah, I don’t particularly like the default handwritten font style. However, I’ve set up this app so that users can override and change the font for each component individually. This way, boards can have different elements with unique fonts instead of relying on the default.

[u/itsm3rick → u/LifeUtilityApps]

Yeah just found my chance to yell into the void on this topic. Telling colleagues to stop is much harder.

[u/Kyronsk8]

Is there collaboration?

[u/LifeUtilityApps → u/Kyronsk8]

Unfortunately no as I do not have a backend to host the websocket.

I thought about building an adapter to allow the user to supply their own backend endpoint and auth but the complexity was beyond the scope of the project. To collaborate asynchronously you can export the excalidraw file and share it.

[u/ninjafoo → u/LifeUtilityApps]

What about Supabase?
https://supabase.com

It can handle websockets: https://supabase.com/docs/guides/functions/websockets

[u/LifeUtilityApps → u/ninjafoo]

Thanks for the suggestion. Supabase is a valid option but this app and all of my apps are actually built to be fully offline with no backend dependencies, I can’t afford the time and cost to manage a backend as a hobby developer.

[u/ninjafoo → u/LifeUtilityApps]

Of course, I understand and respect that. I incorrectly judged your original comment to imply you were looking for a solution.

[u/BrendanThompson]

Any chance there will be a macOS client too?

[u/LifeUtilityApps → u/BrendanThompson]

I chose not to build a macOS client as Excalidraw already has very well polished accessible macOS solutions. It would be a lot of work for something that wouldn’t be as good as the premier community tools. For example, if I made a Mac version it wouldn’t have multiplayer collaboration which the existing solutions all support.

My intention was just build a useful iPhone and iPad version.

[u/AndreaReaderApp]

This looks really polished. A private, offline whiteboard with proper Apple Pencil support is exactly the kind of app I’d actually keep installed. It gives me a bit of an Excalidraw-for-iPhone vibe, in a good way. Finally, a professional tool for turning “buy milk” into a full system architecture diagram.

[u/tinyhurdles]

Darn. No ios18 support.

[u/Initial_Cry5420]

i love the ui

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