Product and tooling engineering
RPGModder
RPGModder 2.0 turns a destructive modding workflow into a validated transaction with journals, rollback, migration, and a redesigned cross-platform workspace.
Problem
Manual mod installation corrupts clean game state, makes conflicts difficult to reason about, and leaves users without a reliable rollback path.
Engineering approach
- Create a recovery snapshot and transaction journal before modifying the live game, then restore the previous state automatically if validation or deployment fails.
- Model file overwrites, structured JSON merges, and semantic JSON patches explicitly so the Conflicts workspace can expose participants and load-order outcomes.
- Ship self-contained Windows and Linux builds with Nexus nxm:// integration, Steam and Flatpak discovery, Proton-aware launching, and secure Linux credential storage.
Outcome
- Version 2.0 migrates previous installations non-destructively and protects every deployment with validation, snapshots, journals, and automatic rollback.
- The release passed 42 automated tests and verified self-contained Windows x64 and Linux x64 packages, including Steam Deck-style Linux workflows.
The hardest problem
Make a mod manager safe enough that a failed deployment never costs the player their game.
Mods overwrite each other's files and merge into shared JSON; a crash mid-deploy leaves a half-patched game, and telling users to reinstall destroys their configuration along with the corruption.
Snapshot before touching the game, journal every write, validate before committing, and roll back automatically on any failure, so the worst case is the previous working state.
How I worked through it
Rollback is only trustworthy if the deploy model knows what each mod actually did. File overwrites, structured JSON merges, and semantic JSON patches are modeled as distinct operations, which is what lets the Conflicts workspace show who wins a load-order fight and why, the same model that makes undo precise.
Version 2.0 had to protect installations created before any of this existed, so the migrator upgrades old profiles non-destructively and brings them under the same snapshot-and-journal protection instead of asking users to start over.
Technologies
- C#
- .NET
- Avalonia
- Transactional deployment
- JSON patching
- Nexus Mods API
- Steam
- Proton
- Secret Service