Free and open source
AI changed how presentations are made. slidecast changes how they're given: full control in your hand, and an audience that becomes part of the presentation.
Scroll to see how it worksMore and more talks are written in HTML: you ask an AI assistant for a deck and get back a single index.html. It looks great, and it can hold anything a web page can.
What it lacks is everything PowerPoint gives you on the day.
You give it your deck. slidecast keeps track of the slide you are on and sends it to every screen that shows the deck.
It lives on your own computer or on a server, depending on how you use it: on your laptop just for today's class, or on an always-on machine that your audience can reach at any time.
slidecast has an admin page where you upload your decks and write the speaker notes, slide by slide. They are saved next to the deck, so they travel with it.
There you also choose who needs a password: the presenter, the viewers of a private deck, or the admin. And you can make the site yours, with your own name and colour.
The current slide, the next one, your speaker notes, a timer and a clock. Only you can see it.
Your notes stay with you; the projector gets nothing but the slides. Open the viewer on it, press F for full screen, and you are ready.
Arrow keys, space or any presentation clicker. Each press travels through slidecast to every screen showing the deck, in well under a second.
Leave the laptop on the lectern. The presenter view also works on a phone: your notes in your hand, and a big button to move on.
Students or colleagues open a link and see the slides on their laptop or phone, in step with you. Handy for the back of a big room, or for anyone joining from home.
A slide is a web page, so it can hold simulations, sliders, quizzes or live charts. Each person plays with them on their own screen while you keep presenting.
Someone missed a point? With Can go back, viewers can look at earlier slides on their own screen, never ahead of you, while you keep presenting. A Back to live button takes them back to your slide.
You can also lock everyone to your slide, or let them browse freely, and switch in the middle of the talk.
Press B and every screen in the room goes black. Press it again to come back.
slidecast lives on a computer you control: the laptop you present from, another computer at home or at work, or a small always-on server such as a Raspberry Pi.
Reach it from anywhere through Tailscale or Cloudflare Tunnel. No account, no cloud service, no tracking.
See it for real
The problem it solves, a class with a laptop, a projector and a phone, and the rest of what it can do. Recorded straight from slidecast.
Use cases
From a Monday morning class to a talk followed from home. Pick yours.
Your laptop on the desk, the slides on the projector, and each student following on their own phone or laptop.
Present from your phone and leave the laptop behind. The back rows follow on their own phones instead of squinting at a distant screen.
Let people go back over a step or explore the deck freely while you guide the session, then bring everyone back to your slide.
Put slidecast on an always-on server and share one link. People in the room and far away see the same slide at the same moment.
Features
Current and next slide, speaker notes, timer, clock and a button to black out every screen.
Keyboard, a presentation clicker, or your phone. Clickers work out of the box.
The projector, phones and laptops follow your slides within a second, on the same Wi-Fi or across the Internet.
Write them slide by slide in the admin panel. They are saved next to the deck and travel with it.
A deck is a folder with an index.html. The docs include a ready prompt for your AI assistant.
Runs on your own machine. Decks run in a sandbox, so a downloaded deck cannot touch your passwords.
Made for AI decks
Three steps from an idea to a deck that works in slidecast from the first try, speaker notes included.
index.htmldeck.jsonWrite a presentation as ONE self-contained index.html file for slidecast.
- A fixed 1600×900 stage scaled to the window (transform: scale), one
<section class="slide" id="…"> per slide with a short, unique, stable id.
- Reveal content in steps inside a slide with data-step="1", data-step="2"…;
a slide's step count is its highest data-step + 1 (set data-steps="N" on the
section).
- Expose the slidecast native API, defined before the load event:
window.SLIDECAST_DECK = { version: 1, steps: [{slide, step}, …],
go(index) {…}, current() {…} };
and after every change dispatch
window.dispatchEvent(new CustomEvent('slidecast:change', {detail: {index}})).
- If window.__SLIDECAST__ exists, do not bind any keyboard, click or swipe
navigation; otherwise ArrowRight/Space/PageDown go forward and
ArrowLeft/PageUp go back.
- No external network requests, no localStorage, no cookies, no fetch.
Inline images as data: URLs or reference files next to index.html.
- Interactive widgets (buttons, sliders, canvases) go inside an element with
the data-interactive attribute.
- Also write deck.json with {"slidecast": 1, "title": "…", "slides": {"<slide id>":
{"notes": "speaker notes in Markdown", "steps": {"1": "note for step 1"}}}}.
Right after the prompt, describe your talk. A line is enough to start; the more you tell it, the closer the first draft.
A 10-minute talk on photosynthesis for 12-year-olds.
A 20-minute lesson on planetary orbits for a Year 9 physics class. About 10 slides: open with a question, explain Kepler's third law step by step, add a slider to explore how distance changes the length of a year, and end with a four-option quiz. Clean, dark design. Speaker notes for every slide.
Turn these notes into a deck for a conference talk, one idea per slide, with speaker notes for me: [paste your outline here]
Una clase de 15 minutos sobre la Revolución Francesa para 4.º de ESO, con una línea del tiempo interactiva y notas para el profesor.
Put the index.html and deck.json your AI wrote in a folder, zip it and drop it in slidecast's admin page. It's ready to present, notes and all.
Only have the .html? Upload it on its own and write the notes in the browser.
More about the format in the deck format guide.
Get started
Free, and it runs on the computer you already have. Pick your system and where your audience will be.
For a laptop and a projector: the presenter view on your screen, the slides on the projector.
Your phone as a remote, and an audience following on their own devices, all on the same Wi-Fi as you.
Download the LTS version from nodejs.org and install it like any other program.
Using Homebrew? brew install node works too.
From nodejs.org or your package manager. slidecast needs version 20 or newer: check it with node --version.
Download the ZIP and unzip it, or with git:
git clone https://github.com/Pablomg02/slidecast.gitOpen the folder, right-click an empty space and choose Open in Terminal. On Windows 10, click the address bar instead, type cmd and press Enter.
Open Terminal, type cd and a space, drag the slidecast folder onto the window and press Enter.
Open a terminal and cd into the slidecast folder.
Other devices need it to move the slides, so nobody else can. 8 characters or more, with a letter and a digit. You only do this once.
node bin/slidecast.js passwd presenternpm installnpm start -- --host 0.0.0.0Then open 127.0.0.1:4321/admin in your browser. If Windows asks, allow slidecast on private networks.
./start.shThe first time it installs what it needs. Then it opens the admin page in your browser.
./start.sh --networkThe first time it installs what it needs. Then it opens the admin page and prints the address other devices can use.
To stop it, press Ctrl+C or close the terminal.
Upload your deck in the admin page (an .html file, or a .zip with its folder) and click Presenter. Click Open viewer, drag that window to the projector and press F for full screen.
Upload your deck in the admin page and click Open next to it to open its room. slidecast shows an address like http://192.168.1.20:4321:
http://192.168.1.20:4321, which takes them to the open room, and taps Watch;…/<deck>/present and type the presenter password.Devices can't connect? Check they are on the same Wi-Fi and that your firewall allows port 4321. Some public or university networks block it; then the guide below has you covered.
Want to know more? Visit the GitHub repository.
Make me a deck about planets for my Year 9 class
index.html Here's your presentation!
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