Apps, AI tools, and technology by Devin Tassin

Building simple, powerful software for real people.

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Projects

A growing collection of apps and tools focused on real-world use, not buzzwords.

MesoBuilder

A training app for lifters and coaches that makes it easy to build mesocycles, log every set, and get automatic progression suggestions week to week.

  • Separate workflows for lifters and coaches
  • Progressive overload suggestions based on performance
  • Clean, affordable alternative to spreadsheet tracking
Visit mesobuilder.app →
MesoBuilder app dashboard preview
What's new v2.3 · June 6, 2026

v2.3 · June 6, 2026

  • Redesigned iPad app that uses the full screen instead of stretching the iPhone layout
  • New iPad coach workspace for viewing clients, programs, and templates side by side
  • Split-view template library on iPad, now open to everyone, with a quick preview before you use a template
  • Smoother navigation, cleaner client management, and stability improvements

v2.1 · May 23, 2026

  • New scheduling step when starting a mesocycle, with Fixed, Rolling, and Flexible options
  • More accurate reminders and schedules for flexible and rolling programs
  • Smoother program creation with clearer confirmations and completion summaries
  • Accessibility improvements across controls, pickers, steppers, and charts

Upcoming Projects

I'm always working on something new. Here is a sneak peek at what is currently in development.

About Tassin.Tech

An independent studio building practical tools. Tassin.Tech explores where fitness, security, and everyday tech all overlap.

I build things I actually want to use: training tools that make sense in the gym, simple websites that are easy to maintain, and AI-powered utilities that save time without adding clutter. On the side I run local LLMs on my own hardware and tinker with security and automation tooling. That exploration feeds back into the apps.

Most projects start as something small I need in my own life and grow from there. If it isn’t practical, opinionated, and honest about what it can and can’t do, I’m not interested.

Contact

Questions, ideas, or feedback about MesoBuilder or anything else? Reach out.

Email:

contact@tassin.tech