{"id":3788,"date":"2026-09-28T09:32:18","date_gmt":"2026-09-28T13:32:18","guid":{"rendered":"https:\/\/blogs.mathworks.com\/graphics-and-apps\/?p=3788"},"modified":"2026-09-28T09:32:18","modified_gmt":"2026-09-28T13:32:18","slug":"plain-text-matlab-apps-in-r2026b-a-diff-you-can-read","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/graphics-and-apps\/2026\/09\/28\/plain-text-matlab-apps-in-r2026b-a-diff-you-can-read\/","title":{"rendered":"Plain-Text MATLAB Apps in R2026b: A Diff You Can Read"},"content":{"rendered":"\r\n\r\n\r\n
\"Portrait<\/td>\r\nGuest Writer: Daniel Cuccia<\/a>\r\n<\/strong>Danny is a software engineer on the App Building Infrastructure team. He started his career at MathWorks in 2018 on the App Designer team. As his understanding of how MATLAB's internal systems fit together grew, through work on features like the app code generation architecture, he found his way to the infrastructure team, where he now works on how app architecture itself works in MATLAB. Danny has studied everything from audio engineering to simulation programming to game development, but has always been drawn to software architecture as the backbone of what he builds. Outside of MathWorks he plays countless instruments, snowboards, and is always picking up a new hobby alongside his family.<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n \r\n\r\n
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For years, one of my quiet frustrations with App Designer apps was a file: the .mlapp, and I know I\u2019m not alone. It held everything: layout, callbacks, helper methods, the whole app, in a single classdef, all inside one binary file. That's tidy in principle, and fine for my simple casual apps. In practice, it nudged, almost forced, all of us toward keeping everything in that one file, and those .mlapp files grew. And grew. Until \"<\/span>let me just find where the button callback lives<\/span>\" turned into a spelunking expedition through a multi-thousand-line classdef.<\/span><\/div>\r\n
The part that really got me wasn't the size, though. It was what happened when two people tried to work on the same app. Or when I opened my own project six months later and wanted to see what I'd changed. The answer from source control was, essentially, a shrug: \"something in the app is different.\" Gee... thanks.<\/span><\/div>\r\n
So a while back, I set out to fix a specific, unglamorous problem: make MATLAB apps something you can actually collaborate on.<\/span><\/div>\r\n

The thing I actually wanted: a diff you can read<\/span><\/h2>\r\n
Here's the whole dream, and it's a modest one. I wanted to open a pull request and see this:<\/span><\/div>\r\n
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Not \"binary file changed.\" Not a re-render of the entire app. Just: <\/span>someone doubled the emitter speed.<\/span> I can review that. I can approve that. I can blame that (lovingly).<\/span><\/div>\r\n
To get there, an app needs to live as plain text: text that a human reads and recognizes, and that a version control tool can line up side by side. That's exactly what the new plain-text app format gives you. Save-as -> change the file format (or change the default in the App Designer preferences), and your app becomes two files which App Designer manages for you that sit happily in Git, Subversion, or whatever you use:<\/span><\/div>\r\n