cupertino-filesPages, Numbers, and Keynote. In TypeScript.

Open, edit, and save Apple's document formats anywhere JavaScript runs. No Mac required. An open reverse-engineering, still under way—designed so every byte you don't touch comes back exactly.

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The format, documented

GitHub

A cardboard tray of apples, each wearing a cupertino-files fruit sticker

The whole stack, from hex

Snappy, protobuf, ZIP, IWA archives, the object graph—reimplemented by reading real documents until they made sense. A typed model on top, so you get to think in paragraphs and slides instead.

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Bytes in, bytes out

What you don't edit is left exactly alone—that's the design, held against every fixture we could legally get. Documents from app versions we haven't met yet should ride along unharmed.

∅

It mostly just works

And where it doesn't, it declines with a reason—a clear error beats a plausible guess. Password-protected documents are refused on principle.

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Markdown in and out

Every document exports to Markdown, tables to CSV, pictures and comments along; a Pages document, a Keynote deck or a Numbers table is written from Markdown or CSV, from the API, the MCP tool or the command line.

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For the next implementer

The format written down as we learn it, a language-neutral conformance suite, and the recovered schemas with their provenance. Port it, check yourself, tell us what we got wrong.

Say hello

installyour first edit

npm install cupertino-files

import { readFileSync, writeFileSync } from "node:fs";
import { PagesDocument } from "cupertino-files";

const doc = PagesDocument.load(new Uint8Array(readFileSync("Report.pages")));

doc.appendParagraph("hello");   // the traditional first word
doc.replaceText("2024", "2025");
doc.sections()[0].setHeaderText("Confidential");

writeFileSync("Report 2025.pages", doc.save());

Open the result in Pages. It opens—and if yours ever doesn't, that is a bug report we genuinely want. (How we know it usually does.)

one more thing …

This isn't only a library. It's the format, written down: a specification measured from real documents, a conformance suite any implementation can test against, and the recovered schemas with their provenance. If you're building iWork support in another language—or another decade—the knowledge is yours too.