A Rabbit Hole

I decided to build a web-based word processor from scratch. It's not based on ProseMirror or contenteditable or any native web APIs; it has its own editor engine and rendering engine that draws to HTML5 Canvas.

"Why would you do this?" To learn how, to practice the new art of agent-assisted coding, to rethink how a word processor interface can behave.

Revise is a simple application on the surface. You can create documents, with or without an account. You can use basic formatting, add lists, and add images. I'm still working on support for tables and links. You can export to PDF or DOCX.

Under the hood, things are more complex. Revise docs are collaborative just like Google docs. You can share documents with anyone and edit them together. You can also publish them as read-only posts.

There's also a built-in AI agent, with a model picker like Cursor. This agent has tools for editing your document in an agent loop. You can ask it for feedback, proofreading, or automatic revisions. It can iterate with multiple turns. This has been an excellent project to learn how to build an agent loop.

Revise tracks document change history automatically, if you use an account. You can jump back in time to any point and see the changes in that snapshot. Having my own rendering engine gives me a lot of control over how these are visualized.

I've learned that I took for granted all the nuances of how word processors behave. Simply making the cursor behave correctly (when splitting lines, when pasting content, when navigating up and down) is not trivial.

What's Next

Revise is currently in a beta state - usable for basic document composition like drafting emails, essays, or notes. Here's what's coming next:

Passive AI proofreader - The AI will actively watch as you work, adding non-intrusive suggestions beyond just typos and grammar. A simple MVP exists in the "Analysis" tab.
Templates - First-class template support with annotated fill-in areas and an AI wizard to guide you through them. Useful for forms, contracts, and replacing the copy-paste-and-edit workflow.
"Git blame" for documents - Point to any paragraph and see its full change history, including who added which words and when.

I've always liked the Paul Graham quote "find something people are doing, and figure out a way to do it that doesn't suck." I think there are a lot of things like this with word processing. The basic UX hasn't changed in 20+ years. I think there's room to design a "post-AI" word processor, which leverages the fact that machines can now understand language and maybe even think.