Around summer/fall of 2025, I started using 'plan mode' quite a bit more. When I would cmd+click into a newly created markdown plan, macOS would open Xcode. This was slow, didn't have native rendered viewing, the list goes on. I started working on a markdown viewer to easily open, review plans before I sent Claude on their way. The Markdown Viewer was born! It came from inspiration from the great Preview Mac app.

For Christmas our family got a Bambu A1 3D printer (fantastic btw!) and I wanted to easily preview 3d files before opening/sending to the printer, etc. Well, I started up a 3d viewer. Yaml, CSV, Text viewers all followed.

As a responsible engineer, I started seeing patterns, so I DRY'd it up w/a core library, but was stuck with how to update each one, and to consistently get around the Apple notarizing/signing. So I created the Viewer Toolbox. The toolbox is an easy way to install and update my viewer apps. Now I can "write once, use everywhere" ;). I have a few Macs at home that I can now just click "Update" on the app and it's ready to go.

Originally, I opened up the Apple Mac Store to see if there were any quick viewers, but most were paid or had in-app purchases. I didn't think one app by itself was worth charging for, so my friend suggested I put the Toolbox up online for a price. Makes sense! So the individual apps are free, and if you want to get updates or new viewers, download the Toolbox! The individual apps will never have a paid version. This was to solve my own problem.

I was debating about writing this, but with Simon's recent blog post about his presentation app and how that Microsoft was adding markdown and AI support to Notepad, I had to launch this today.

Minor tech tangent: they're all native Swift/SwiftUI, universal binaries, no Electron, and each one is 1-2 MB. I share a small Swift package (ViewerCore) across all of them for common functionality like search, theming, and web view rendering. Simple, fast, free and portable are key here.

Hopefully this helps someone :).

Thank you!

Ryan

https://ryanlitalien.com/simple/

https://ryanlitalien.gumroad.com/l/viewer-toolbox (photos of the apps are on here)