Casual Editor is unclaimed —

Casual Editor

Word-flavored web document editor·docs.casualoffice.org

Free plan · Open source See pricing ↓

Casual Editor is an open-source, real-time collaborative .docx editor that runs in the browser. It uses ProseMirror with an OOXML-preserving model, a React + Bun frontend, and a stateless Go WebSocket gateway implementing the y-websocket protocol for co-editing via Yjs. Document persistence is delegated to a pluggable host integration (an inline share-link implementation for v0, with WOPI/JWT-API support planned). Users can open a .docx file from their computer or start from a template, edit it collaboratively, and save it back as .docx.

What it's for

Real-time collaborative document editing in the browserOpening and saving native .docx filesCreating resumes and cover lettersWriting meeting notes and project proposalsDrafting educational documents (essays, lab reports, course syllabi)Self-hosting a docx editor via Docker

Features 12

14-template home gallery with real first-page PNG previews
Open a file directly from your computer
Open and save native .docx files in the browser
Per-tag round-trip audit in CI
Planned AI features: inline ask, rewrite panel, and DocOps chat panel
Pluggable host integration (inline / WOPI / JWT-API behind a single Go interface)
ProseMirror editor with an OOXML-preserving model
Real-time multi-user co-editing via Yjs and y-prosemirror
Stateless Go WebSocket gateway with no database or on-disk update log
Templates across Personal, Work, Education, and Career categories
Three-way fidelity harness comparing output vs LibreOffice and OnlyOffice DocumentBuilder
Word-compat heuristics behind an opt-in flag (e.g. last-row closing border)

At a glance

free tieropen sourceself-hostable

TypeWeb app

DeploymentHybrid

PlatformsWeb, Linux

CompanySachin Sarwa

Integrations

OnlyOffice DocumentBuilderLibreOfficeAnthropic API

Pricing

Product is free and open source; JSON-LD offer lists price 0 USD, no paid plans stated.

FreeFree

Open-source and free; can be self-hosted via Docker or used as the hosted web demo.