Generating Word Docs in the Browser with docx.js

I used to think PDF was the only professional document format. Then I started building B2B apps.

Here is the truth: Business users love Word. They want to edit the contract, tweak the report, or copy-paste the data. If you only give them a PDF, you are actually making their life harder.

docx.js is the library that changed my mind. It allows you to generate .docx files entirely in the browser (or Node.js) without any server-side dependencies.

Installation

npm install docx

The “Hello World” of Word

Unlike HTML strings, docx.js uses an object-oriented approach. You build a tree of objects: Document -> Section -> Paragraph -> TextRun.

import { Document, Packer, Paragraph, TextRun } from "docx";
import { saveAs } from "file-saver"; // You'll need this for browser download

const generateDoc = () => {
  const doc = new Document({
    sections: [
      {
        properties: {},
        children: [
          new Paragraph({
            children: [
              new TextRun("Hello World"),
              new TextRun({
                text: " This is bold",
                bold: true,
              }),
              new TextRun({
                text: "\tAnd this is a tabbed text",
                bold: true,
              }),
            ],
          }),
        ],
      },
    ],
  });

  Packer.toBlob(doc).then((blob) => {
    saveAs(blob, "hello-world.docx");
  });
};

Understanding the Structure

1. Document: The root object. Contains global settings like metadata (author, title) and background color.
2. Sections: Think of these as chapters or page layouts. You can have a landscape section followed by a portrait section.
3. Paragraph: The block-level element. Handles alignment, spacing, and indenting.
4. TextRun: The inline element. Handles font size, color, bold/italic, and font family.

Why This Matters for Indie Hackers

If you are building a SaaS, “Export to Word” is often a premium feature you can charge for.

• Legal Tech: Generate NDAs or contracts filled with user data.
• EdTech: Create worksheets or lesson plans teachers can modify.
• Reporting: Generate weekly status reports managers can tweak before sending to their boss.

It is a low-effort feature with high perceived value.