DevTrainy

The Problem

Most developers prepare for interviews by reading articles once and hoping it sticks. There was no tool that combined real coding questions, structured repetition, and honest progress feedback in one native iOS app.

DevTrainy was built to fix that. The idea was simple: if you can train muscle memory through repetition, you can train technical knowledge the same way.

Spaced Repetition That Actually Works

The app surfaces questions based on how well you've answered them before. Get something right consistently - it appears less often. Struggle with a topic - it keeps coming back until the concept is solid. The result is a preparation flow that adapts to you, not a static list you scroll past.

Built in SwiftUI, End-to-End

The entire app was written in SwiftUI and Combine, with Swift 5.6 patterns throughout - Observable, SwiftData, and a clean MVVM architecture. The backend was built with Vapor. No third-party black boxes, no bloat.

Shipping a full-stack product solo meant making deliberate trade-offs: a lean content model, an onboarding flow with zero friction, and a UI that doesn't get in the way of learning.

Real-World Coding Tasks

Beyond theory questions, DevTrainy includes actual coding challenges drawn from real interview formats - with hints, solutions, and explanations written by a developer who has been on both sides of the interview table.

Progress is tracked per topic and per session, so users can see exactly where they are strong and where the gaps are.

Shipped, Validated, Sold

DevTrainy reached the App Store, gained real users, and was eventually acquired. The process - from concept to AppStore to exit - confirmed the value of owning the full stack: product, design, engineering, and distribution.

What It Proved

Building and selling DevTrainy validated that you can take a developer tooling idea from a sketch to a live product to an exit without a team, just by making every decision count and staying close to the user.

Stack

SwiftUI · Combine · Swift 5.6 · SwiftData · Vapor · MVVM · App Store · CI/CD via Fastlane