So, after several months of work, I built something where branching lives inline.

Quillium is a desktop writing app for long-form creative work such as novels, essays, memoirs, built with Tauri + SvelteKit and targeting desktop first because reliability is very important. Data stays local in SQLite with a crash-safe event log and automatic backups.

You can fork any passage into multiple versions that sit right inside the document and switch between them with a keybind. Undo works across the whole tree because it's one shared history regardless of where you're editing. Revisions can also nest INFINITELY: a version of a passage can itself have versions.

Of course, there's AI features but that's explicitly hidden because writers (who this app is marketed to) are extremely AI-averse. I know the HN community likely isn't though ;)

For those who want it (BYOK): there's an AutoAI mode that leaves notes as you write, and reader personas for parallel feedback from different simulated audiences. The disagreements between personas tend to surface real ambiguity better than a single "make this better" prompt.

Still early. Most curious what people think about the revision/branching model specifically because that's the most important part.