Open-source alternatives to Gamma: 5 AI presentation builder tools compared
Moving deck building off a hosted service means giving up the visual editor Gamma gives you and taking on the authoring tool yourself. Readers who write their own slides should look at hakimel/reveal.js and slidevjs/slidev first; presenton/presenton is the one that keeps the prompt-to-deck path.
What Gamma does, and why people look elsewhere
Gamma is a hosted tool that turns a document, a prompt or a pasted outline into a slide deck and publishes it as a web page.
- the decks and the material behind them are stored on the vendor's servers
- the editor is a web application, so a deck you keep is a copy on the vendor's side rather than a file
- export produces images and documents, so the layout and its interactions do not travel with the deck
The candidates at a glance
| Project | Licence | Maintenance | Language | GitHub stars | Install |
|---|---|---|---|---|---|
| hakimel/reveal.js | MITPermissive: commercial use allowed | Commits in the last six monthsLast push September 30, 2026 | JavaScript | 72,448 | See analysis |
| slidevjs/slidev | MITPermissive: commercial use allowed | Commits in the last six monthsLast push October 2, 2026 | TypeScript | 48,955 | Command documented |
| marp-team/marp | MITPermissive: commercial use allowed | Commits in the last six monthsLast push July 29, 2026 | TypeScript | 12,670 | See analysis |
| impress/impress.js | MITPermissive: commercial use allowed | Commits in the last six monthsLast push July 23, 2026 | JavaScript | 38,157 | See analysis |
| presenton/presenton | Apache-2.0Permissive: commercial use allowed | Commits in the last six monthsLast push October 22, 2026 | TypeScript | 11,274 | See analysis |
Each alternative in detail
hakimel/reveal.jsThe HTML Presentation Framework. It enables anyone with a web browser to create beautiful presentations for free.
- Best for
- A developer who wants slides to live in version control as HTML, with nested slides, Markdown, Auto-Animate and a PDF export path that runs from a static file server.
- What you give up
- It has no graphical editor and no prompt-to-deck generation: the README points to a separate paid service for visual editing, so a team that expects a drag-and-drop canvas has to build one or buy that service. The 6.0 line also changed enough that plugins and custom themes written for 5.x need checking before an upgrade.
slidevjs/slidevPresentation Slides for Developers
- Best for
- A developer whose decks contain code, diagrams or maths, where live coding, Shiki highlighting, Mermaid diagrams and KaTeX matter more than a visual canvas.
- What you give up
- Presenter mode, drawing and recording have no representation in the PDF, PNG or PPTX exports, so a deck that has to stay interactive after you hand it over loses those features. The version has to be pinned, because three releases including a major one landed within about four hours on 2026-09-16, and the version string lives in three package.json files that one bump command keeps in step.
- First install step
- Full setup guide
npm init slidev
marp-team/marpThe entrance repository of Markdown presentation ecosystem
- Best for
- A team that wants its slides to live in the same Markdown files and the same Git history as its notes, and is content with a thin Markdown-to-deck pipeline.
- What you give up
- This repository is the entrance to the family, not the converter: its package.json is private and carries no runtime code, so the tool you install is Marp CLI or the VS Code extension from sibling repositories. There is no hosted editor, no slide DSL with animation primitives, and no single repository to pin if you want one dependency.
impress/impress.jsIt's a presentation framework based on the power of CSS3 transforms and transitions in modern browsers and inspired by the idea behind prezi.com.
- Best for
- A developer who wants a non-linear, spatial presentation where the geometry of each slide is written by hand in HTML and CSS rather than laid out on a canvas.
- What you give up
- The framework targets modern browsers only, so older clients are out of scope, and it ships one built-in template for conventional decks. Fixes are merged into the master branch rather than cut as tagged releases, so there is no version contract to pin, and the tooling that would give you a visual editor is a separate project.
presenton/presentonOpen-Source AI Presentation Generator and API (Gamma, Canva, Beautiful AI, Decktopus, Presentations AI Alternative)
- Best for
- A team that wants the prompt-to-deck path Gamma is known for, on its own infrastructure with its own model keys, and an output file that a person can still edit in PowerPoint.
- What you give up
- Every published tag is a beta, so there is no stable release contract to pin, and the compose file carries edges around the host port mapping and a callback port that have to be read before the first start. The image defaults to the amd64 platform, and a template change does not survive a container restart without a rebuild.
- Moving from Gamma
- An uploaded PowerPoint file can be taken as the design to work from, so a deck built elsewhere can be reworked and exported again as an editable PPTX or PDF.
Three authoring models: HTML, Markdown files and a prompt
Gamma's promise is a single box: you paste a document or a prompt and get a deck back, published as a web page. Nothing on this list works that way except presenton/presenton. The other four are authoring tools, and the real difference between them is what a slide is before it becomes a deck.
hakimel/reveal.js treats the deck as HTML. A slide is a section element in a document, nested slides are vertical stacks, and the browser handles the movement between them. Markdown works, Auto-Animate animates matching elements from one slide to the next, and the same file can be printed to PDF. There is no build step and no server. The output is a folder of static files, which is the cheapest possible deployment.
slidevjs/slidev treats the deck as a Markdown file read by a Vue application. That choice buys live coding, Shiki highlighting, Mermaid diagrams, KaTeX maths, an icon set, presenter mode on a second screen, drawing and recording, all wired into the deck rather than bolted on afterwards. The price is the toolchain: Vite serves the deck in development, UnoCSS handles styling, and themes arrive as npm packages, so the deck is only reproducible if the dependency tree is pinned.
marp-team/marp is the thinnest of the four. The repository you would clone is a landing page; the converter lives in Marp Core and the command line lives in Marp CLI. What you get is a deterministic Markdown-to-deck pipeline that produces HTML, PDF, PPTX and images, which is what you want when a deck has to survive a code review.
impress/impress.js is the odd one out. Its slides are positions in a three-dimensional space and the movement between them comes from CSS3 transforms, so a presentation can zoom, pan and rotate instead of advancing one flat page at a time.
What you give up: the canvas, the shared link and the file
Gamma keeps the source document, the generated deck and the published page in one place, and the result is reachable at a URL that anyone can open. None of the five candidates reproduces that combination, and the gaps differ in kind rather than in degree.
presenton/presenton comes closest on generation and closest on output, since it exports an editable PPTX or PDF and offers built-in templates with a drag-edit interface. It still produces files rather than a published web page. The other four produce something you can host yourself, but you write the slides instead of generating them. That gap is also why the popular graphical AI deck builders are not on this list: they are closed hosted services with no code to point a reader at and no way to run them inside your own network. The closest open-source analogue is the separate visual editor the reveal.js README recommends, which is a paid service in its own right rather than part of the framework.
Gamma's own export path produces images and documents, so the layout and its interactions do not travel with the deck. That is one reason people start looking at alternatives, and it is worth being precise about what each candidate does instead. A deck written as HTML in reveal.js or as Markdown for slidev or marp stays text, so the layout travels because the layout is in the file. What it does not travel with is the published URL and the editing surface. A team whose real requirement is a prompt in one end and a polished deck on a shareable link at the other will not find a self-hosted answer on this page, only a better-controlled version of a workflow it has to run itself.
What self-hosting each one costs in operations
For reveal.js, slidev, marp and impress.js the operational bill is small, and in one respect counter-intuitive: none of them needs a database, object storage or a background worker. What they need is somewhere to put static files. reveal.js and impress.js are hand-written HTML and CSS, so deployment is a copy to any web server, and the only moving part is your own review process. marp adds a build step, because Marp CLI turns Markdown into HTML, PDF, PPTX or images, and that step is where a pinned version matters more than anywhere else in the list.
slidev is the heaviest of the four without a server. The dev server is a local process, but the deck you ship has to be rebuilt for the target audience, and the version has to be pinned across the three package.json files that hold it. The exported PDF, PNG and PPTX carry none of the interactivity, so a shared deck and a presented deck are two different artefacts.
presenton/presenton is the only candidate here that is a service rather than a file format. It runs in a Docker container or as a desktop application, it talks to a model provider of your choosing, and it keeps templates and generated decks somewhere on disk. That means a container image to rebuild, model API keys to manage or a local model server to run, and a compose file whose host port mapping and callback port need reading before the first start. Its own documentation notes that the published tags are beta releases, so a deployment should pin a tag rather than follow the main branch.
Licences: MIT for four of the five, Apache-2.0 for the fifth
Four of the five candidates are MIT licensed: reveal.js, slidev, marp and impress.js. presenton/presenton is Apache-2.0. For a company running one of these internally, both are permissive licences and the practical difference between them is narrower than the names suggest.
MIT asks you to keep the copyright notice and the licence text alongside copies of the code you redistribute, and it carries no obligation to publish anything you build on top of it. Apache-2.0 asks the same thing and adds two clauses that matter in a corporate setting: an explicit grant of patent rights from the contributors, and a clause that stops a patent holder from suing you for infringing the licence itself. It also carries a patent-termination condition, so a contributor cannot withdraw a patent grant while their code is still inside your product.
Neither licence obliges you to open-source your deck templates, your brand styling, an internal wrapper or the code that drives these tools, and none of the five is copyleft, so there is no condition attached to hosting a modified version over a network. That is the point to check against your own policy: if your legal team has a standing rule about network-hosted copyleft software, this list does not raise the question. The licence conditions that do exist are ordinary attribution duties, and the place to read them is the LICENSE file in each repository. Check it before you assume that a dependency pulled in by a theme or a plugin carries the same terms as the tool itself.
Choosing by scenario, and where each one is the weaker choice
For a solo developer who wants a deck in version control, reveal.js is the shortest path: the file is HTML, the output is static, and the PDF export exists when a PDF is what the audience needs. For a developer whose slides contain code, slidev is the better fit, because live coding and syntax highlighting are the parts of a technical talk that take longest to fake. For a team whose notes and slides already live in one Markdown repository, marp is the least surprising choice, provided someone accepts that the converter lives in a sibling repository. For a talk that should feel like a map rather than a list, impress.js is the one with no substitute here.
presenton/presenton is the pick when the input is a prompt or an uploaded document rather than a Markdown file, when the output has to be opened and edited by someone who does not run your tooling, and when the model calls have to leave your network. Its weaknesses are the sharpest of the five: beta tags, a compose file that needs reading, an image that defaults to one CPU architecture, and template changes that do not survive a container restart.
The weaker choice in each pairing is worth naming too. If you want a prompt-to-deck flow, the four Markdown and HTML tools are the wrong instrument, because none of them generates anything. If you want a deck that a non-technical colleague can rearrange, reveal.js, slidev, marp and impress.js are all the wrong instrument, because all four put the layout in the hands of whoever writes the code. Choose the mismatch knowingly, because it is the mismatch that decides whether the project lasts.
Bottom line
Pick reveal.js or slidev if the deck should be a file you own, pick marp if the whole repository is Markdown, and pick presenton/presenton only when the prompt-to-deck path matters more to you than a stable release tag. Before committing, generate one real deck on the machine that will run it, pin the dependency version, and read the compose file end to end.