Document Engine

The programmatic layer for reading, editing, and saving .docx files.

Document Engine is SuperDoc’s programmatic layer for .docx files. Use it when code needs to read, search, edit, format, comment, redline, or save a Word document.

It powers browser editor workflows through editor.doc.*, backend automation through the SDKs, and shell workflows through the CLI.

Building with AI? Start with Use SuperDoc with AI. AI integrations use the same document operations, but the setup path depends on whether you’re using MCP, SDK tool definitions, or a visible editor.

Surfaces

Three surfaces, same operations underneath.

Surface	Best for	Runtime
Document API	Programmatic edits against an open editor	Browser
SDKs	Node / Python backend automation	Server
CLI	Shell scripts and CI pipelines	Any shell

How it works

The Document API is the operation contract. It defines every document action SuperDoc supports (search, replace, insert, format, comments, tracked changes, lists, tables) as a typed input/output pair.

• The browser editor exposes those operations as editor.doc.*.
• The SDKs manage a CLI process and expose the same operations as typed Node and Python methods.
• The CLI runs in persistent sessions: open a document, run operations, save and close. Each operation takes arguments and emits JSON output.

All three call the same underlying engine. A redline written by your backend, a CI script, and a browser editor produce the same result on the same .docx file.

Which surface should I use?

Your setup	Start here
Web app with a visible editor	Document API
Custom UI around a visible editor	Custom UI + Document API
Backend automation (Node / Python)	SDKs
Shell scripts or CI	CLI
Serverless function (Lambda, Vercel, Workers)	SDKs or CLI
Claude Code, Cursor, Windsurf, or model tools	Use SuperDoc with AI

Where to next

Document API

The operation contract. Every method the editor and SDKs share.

SDKs

Node and Python typed methods for backend automation

CLI

Scriptable DOCX operations from the shell

Diffing

Compare two DOCX files. Produce a redlined third document.