PowerPoint Font Manager

AI-assisted project. This codebase was created with Claude (Anthropic), directed and reviewed by a human author. The scanner is verified against three real presentations of different provenance — one from Canva, one from Office with embedded fonts, one 316 MB deck that names almost no fonts explicitly — and its installed/missing verdicts were checked font by font against CoreText's own list on macOS. The bundle's Windows installer script has never been run on Windows; the macOS and Linux ones are syntax-checked but have not been run against a real font install. Check the bundle on a spare machine before you rely on it in front of a client.

Drop in a .pptx. Find out which fonts it actually uses, which of those are installed here, and take away a sidecar .zip that installs the rest on the machine that needs them.

Everything happens in the browser. The deck is never uploaded anywhere.

Why not just search the file for font names

Because you get a wrong answer that looks right. Every PowerPoint theme carries a script fallback table — a list of fonts to reach for if the deck ever contains Japanese, Devanagari, Khmer, Syriac and so on. It is there whether or not a single such character exists in the presentation.

Searching a real deck for typeface= finds 39 fonts. It uses two. The other 37 are that table, and a tool that lists them will send you off to install Mongolian Baiti and DokChampa for a slide that says "Welcome" in Calibri.

The second half of the problem is that decks name faces, not families:

Three false alarms out of four. This tool resolves the names first, so "missing" means missing.

What it does

Scans slides, layouts, masters, notes, charts and SmartArt, resolves theme references (+mn-lt and friends) through the theme the slide actually inherits, and sorts what it finds by how much it matters — used on a slide, inherited from a layout or theme, or only present somewhere incidental.

Checks what is installed, using the Local Font Access API where the browser has it, and text-width measurement everywhere else. The fallback was checked against CoreText on macOS across nine fonts and agreed on all nine.

Finds replacements across two catalogues — 1,942 Google Fonts families plus 119 more from Fontsource that Google does not carry — matched after the name is normalised, with near-matches offered when there is no exact one (a missing Garamond suggests EB Garamond and Cormorant Garamond).

Substitutes what cannot be shared. The fonts most often missing are the ones a deck picks up just by being written on Windows or a Mac — Calibri, Cambria, Arial, Times New Roman, Courier New, Georgia. None may be redistributed and none are on Google Fonts, so the app offers metric-compatible stand-ins instead: Carlito for Calibri, Caladea for Cambria, Arimo for Arial, Tinos for Times New Roman. These have the same advance widths as the original, so line breaks hold and text stays inside its box.

Where only a visually similar face exists (Open Sans for Segoe UI), it says so plainly — that swap will move your line breaks, and being told the deck is fixed when it is not is worse than being told the font is missing.

Recognises Adobe Fonts. These can never be bundled — Adobe's terms say the fonts "are not compatible with packaging workflows that involve transferring font files to another user or computer", and there is no API that serves the files in any case. So for a missing one the app names the reason and links straight to the family page, where anyone with a Creative Cloud subscription can activate it.

The desktop app also catches the version of this that looks fine: a font Creative Cloud syncs onto your machine is installed here and nowhere else, so the deck renders perfectly for you and breaks at the venue. It is told apart from an ordinary installed font by where its file lives — Adobe keeps synced faces in its own CoreSync folder — which is why Times New Roman does not get the warning merely for being sold on Adobe Fonts too.

Reports embedded fonts — fonts that travel inside the deck and need no installation at all. Where the format allows, it extracts them as real installable files (see below).

Builds a sidecar .zip containing the fonts, a manifest saying where each came from and under what licence, and an installer for macOS, Windows and Linux that writes to the per-user font directory with no administrator password.

Embedded fonts

PowerPoint's "embed fonts in the file" does not store a TTF. It stores EOT, and what happens next depends on who wrote the file:

Either way the font travels with the deck, so it will render wherever the .pptx goes. The distinction only matters for what can go in the bundle.

Embedded, but can the other end edit it?

PowerPoint offers two kinds of embedding, and they are not the same promise:

The second one ships just the glyphs this deck happened to need, so PowerPoint stops anyone without the font from editing that text. The app reads the setting and labels each embedded font editable or read-only.

It also checks the setting against the file, because the setting is a claim rather than a fact. A Canva deck declares "characters used only" and then embeds a complete Latin face — so it is marked read-only, and told that the face will in fact render anything you add. The reverse happens too, and matters more: a deck that declares every character while carrying a face cut down to 5 of the 95 printable ASCII characters will let you type and then show you nothing. That one gets a warning.

PowerPoint's own embedder compresses its payload, so for decks written by PowerPoint the setting is the only evidence there will ever be, and the app says so rather than guessing.

If a cut-down face ends up in a bundle, MANIFEST.txt says which characters it actually has, before it lists the filename — a subsetted font installs perfectly and then fails on the first character nobody had typed yet.

The bundle, and two traps it works around

There is no such thing as a single self-extracting archive that runs on every OS — a Windows .exe will not run on a Mac. So the bundle is a plain .zip with one small script per platform, and a README that heads off the two ways these normally fail:

• macOS Gatekeeper. Anything extracted from a downloaded zip inherits a quarantine flag, and double-clicking the installer gets "cannot be opened because it is from an unidentified developer". That is not a broken script. The README gives both ways through, plus the no-script route of dropping the fonts on Font Book.
• Windows Mark-of-the-Web. PowerShell refuses to run a .ps1 that came out of a downloaded zip. The bundle ships a .cmd wrapper that unblocks it — run that one, not the .ps1.

Fonts already installed are skipped, never overwritten.

Licensing

The manifest splits the bundle in two. Fonts from Google Fonts carry OFL-1.1, Apache-2.0 or UFL-1.0 and are marked free to pass on. Anything taken off your own machine or extracted from the deck is marked RESTRICTED, because font licences almost never permit redistribution — and permission to embed a font in a document is not permission to extract and install it somewhere else. The bundle is built for moving your own deck between your own machines. Read the manifest before you send it to anyone.

The desktop app

The browser version can tell you a font is missing and hand you a zip. It cannot put the font where the OS looks for it — no browser can. The desktop build is the same app with that last step joined up: find the missing fonts, fetch them, and install them, in one press.

It is also more accurate. It reads the platform's own font registry rather than measuring text widths, so it resolves faces and not just families: Helvetica Neue Medium comes back as installed rather than "the family is there, the weight might not be".

Fonts go to your own account — ~/Library/Fonts, %LOCALAPPDATA%\Microsoft\Windows\Fonts, ~/.local/share/fonts — so no administrator password is needed, and anything already installed is skipped rather than overwritten.

npm run desktop:dev      # run it
npm run desktop:build    # .app / .dmg / .msi / .deb / .AppImage

macOS and Linux only, so far. The Windows install path is written but has never been run on Windows, and the same goes for Linux. See AGENTS.md §9 for exactly what is and is not verified.

Development

npm install
npm run dev
npm test

Fixtures: the real decks used for testing are private and gitignored. A synthetic one is generated and committed, so the suite tests something on a clean clone:

node scripts/make-test-deck.mjs

See CLAUDE.md for the full command reference and AGENTS.md for the design notes and traps.

Run your own copy

PowerPoint Font Manager is a static page, so hosting it yourself is one container serving the built files — the same files the hosted copy serves, running somewhere that still works when the venue has no internet.

Docker. The image is built by this repo's docker.yml workflow on every push and published as ghcr.io/stoatworks-labs/pptx-font-manager:

docker run -d --name pptx-font-manager --restart unless-stopped -p 8538:80 ghcr.io/stoatworks-labs/pptx-font-manager:latest

Or docker compose up -d with the docker-compose.yml in this repo, which maps the same port. Either way it is then at http://localhost:8538/.

Unraid. Search Community Applications for PowerPoint Font Manager — the template is templates/pptx-font-manager.xml in stoatworks-unraid, which is what the CA feed reads.

Stoatworks Burrow lists it under Self-hosted, with the compose file a click away.

The Dockerfile, docker-compose.yml, docker/ and the workflow are generated from fleet.json in stoatworks-unraid. Change them there and regenerate rather than editing them here.

This project is built on other people's work — see ATTRIBUTIONS.md.

Licence

MIT. Part of Stoatworks Labs.