Documents that
run like apps
Capsule keeps your tools and data inside a single .capsule file, with no servers
to manage and no monthly fees.
Build lightweight tools in minutes
Make tools for your own tasks without running a server or paying a monthly fee. You can start from a description, use a template, or write standard HTML and JavaScript.
Start with an idea
Describe what you need in plain text, or write standard HTML, CSS, and JavaScript.
Everything in one file
Produces a single .capsule file containing your interface, assets, and an embedded
SQLite database.
Own it forever
Update features anytime with prompts or code. Your tools run locally on your machine without an internet connection.
Choose an AI assistant below to start building your app.
Shareable apps that live in a single file
Share interactive tools as easily as sending a document, with full local performance and offline storage.
Apps packaged as single files
Forget cloud accounts, servers, and subscriptions. Capsule bundles your user interface, media
assets, and local database into a single, portable .capsule file.
Send it via AirDrop, messaging apps, or email just like a PDF or spreadsheet. Recipients can open the file on their desktop or directly in their browser without installing anything.
Send interactive trackers, calculators, or tools in standard chats. Opening a file works immediately on desktop or via Capsule Web.
Capsules use standard HTML, CSS, and SQLite. Your code and data belong to you, completely independent of proprietary platforms.
Private by default. Open standards inside.
Capsule keeps your data on your device. Every note, checklist, or calculation you save is written directly into the file. There are no tracking scripts, no cloud databases, and no accounts.
Because apps run locally, you can use them on a flight, on a train, or completely offline. When you share a file, you send the data and the interface together.
Untrusted document code runs inside an isolated webview with a strict Content Security Policy. Apps cannot access your local files or make unauthorized network connections.
Data is stored in standard SQLite tables inside the file. You own your information and can inspect, query, or export it using any standard SQLite tool.
Writes are batched into atomic transactions so files stay intact across Dropbox, iCloud, or OneDrive. If copies diverge, Capsule includes a 3-way merge tool to resolve differences.
One file across every operating system
Capsule files are completely cross-platform by default. Open the exact same file on macOS, Windows, or Linux without conversion or special setup.
Your apps launch with full desktop performance on any computer, with native iOS and Android support coming soon.
Opens on macOS, Windows, and Linux without setup or configuration.
Open and run the exact same .capsule files on iOS and Android devices.
Open standards. Sandboxed security.
Designed for durability, privacy, and full data ownership.
Sandboxed webview
Document code runs inside an isolated webview with a strict Content Security Policy. Apps cannot read your local filesystem or make silent network requests.
Single-file SQLite
Data lives in standard SQLite tables inside the file. Atomic commits prevent partial writes during sync, and you can query your data anytime with standard tools.
3-way conflict merge
If you edit separate copies across Dropbox, iCloud, or OneDrive, Capsule includes a 3-way merge tool to inspect changes and reconcile differences safely.
Download Capsule
Capsule is free and open source. Download the app for your platform, or open files directly in your browser with Capsule Web.
Desktop
Web
Mobile (Coming Soon)
Desktop vs. web features
Both environments run the exact same .capsule files with full local data storage.
| Capability | Capsule Desktop Recommended | Capsule Web Zero install |
|---|---|---|
Built-in AI coding agent Iterative coding loop, live previews, and automated schema migration | ||
Native file association Double-click .capsule files directly in Finder or Explorer | ||
3-way conflict merge Visual inspector to reconcile divergent file copies and schema changes | ||
Scoped network proxy Document HTTP requests gated by explicit host permissions without CORS | ||
Offline SQLite engine Complete client-side database execution with zero network dependency | ||
In-place local disk saves Direct atomic commits to files on your local drive | ||
Zero installation Run immediately in any modern web browser | ||
Google Drive integration Open, edit, and save documents directly from Google Drive | ||
| Download for macOS ↓ | Open Capsule Web → |