PL

DevJourney

A desktop app for learning C# and .NET 10 in a real development environment. My own product, built and run solo.

Role
Founder, sole engineer
Period
2026 — now
Stack
Tauri 2 · Rust · React 19 · TypeScript · .NET 10 · Roslyn · Monaco · SQLite · Postgres · GCP Cloud Run
devjourney.app ↗
DevJourney: a lesson on ASP.NET Core on the left, the C# editor and the built-in HTTP request panel on the right.

The problem

Most C# courses teach in a browser sandbox, then leave learners to figure out a real IDE on their own. Bootcamps give you real tooling, but at bootcamp prices. DevJourney sits in between: the tooling of a professional environment, in one app, for the price of an online course.

The product

A course of 670+ lessons across 60 chapters, from what a program is, through OOP, LINQ, async, testing and EF Core, to ASP.NET Core Web APIs and a multi-file final project. Every lesson is written in both Polish and English.

The learner writes and runs real code the whole time:

  • IntelliSense from the bundled Roslyn Language Server, the same engine Visual Studio uses.
  • A real debugger (netcoredbg) with breakpoints, stepping and variable inspection.
  • Real dotnet execution: console apps, web APIs, xUnit tests, EF Core migrations.
  • An AI tutor that reads the learner’s files. It runs on whatever the learner already has: Claude Code, Codex CLI, Ollama or an Anthropic API key.
  • Open in IDE hands a lesson over to VS Code, Visual Studio, Rider or Zed.

What I built

I designed, wrote and run all of it.

  • Desktop app: Tauri 2 with a Rust backend and a React 19 + TypeScript interface. Progress lives in local SQLite, and the app works offline apart from license activation and the AI provider.
  • Engine monorepo: the product-agnostic engine, the .NET runtime and the SQL runtime are separate Rust crates behind one contract, so a second product, DevJourney SQL, runs on the same shell.
  • AI provider layer: one Rust trait over local models, the Anthropic API and the Claude Code and Codex CLIs, with streaming and live narration of the files the agent opens.
  • Licensing and payments: a licensing service on GCP Cloud Run with Postgres, Dodo Payments webhooks that are safe to replay, and license emails through Resend. A customer portal runs on Vercel. The app validates licenses offline with a grace period, and paid lessons ship encrypted.
  • Distribution: signed auto-updates through GitHub Releases.

Stack

Tauri 2 · Rust · React 19 · TypeScript · Monaco · Roslyn LS · netcoredbg · .NET 10 · SQLite · Postgres · GCP Cloud Run · Dodo Payments · Resend

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