Privacy & Data

Stash is designed with privacy as a core principle. This page explains exactly how your data is handled—and more importantly, what doesn’t happen with your information.

No Data Collection

Anonymous Aggregate Telemetry Only

Stash does not track or monitor you individually. The only data collected is anonymous aggregate counters — event names and coarse dimensions, never anything that identifies you:

No personal identifiers: Events carry an event name and coarse dimensions only — never a user id, IP-linked history, tab URL, title, tag, or note
No cookies: No persistent storage for tracking
No fingerprinting: No device or browser fingerprinting
No user accounts: No registration or login required
Opt-out in the extension: Telemetry can be disabled from Settings; the web viewer’s PostHog analytics are cookieless by default

Browser-Only Processing

All tab sharing happens entirely within your browser:

Extension processing: Tab selection and encoding happens locally
Content stays local: Tab URLs and titles are never sent to a server unless you explicitly opt in to short-link sharing; only anonymous telemetry event names (e.g. “stash saved”) leave the device
Client-side expiry: Expiration checked in browser, not on servers

Local Encoding Process

When you share tabs, this is the complete process:

Tab selection: You choose tabs in your browser
Local encoding: URLs and titles are encoded into a share link
Clipboard copy: Only the final share link is copied
No transmission: No data sent anywhere except when you intentionally share the link

Share links contain only what you explicitly share:

Tab URLs: The web addresses you selected
Tab titles: Page titles (max 30 characters)
Version info: For technical compatibility
Expiry timestamp: For automatic link expiration

No personal information is included:

No browsing history
No user identity
No device information
No location data
No timestamps beyond expiry

Data Security

Server Architecture

Stash has minimal server infrastructure:

Viewer only: stash.illo.fyi only renders share links
No storage: No database or persistent storage
No processing: No server-side data manipulation
Static hosting: Viewer site is static files with no dynamic processing

There is one opt-in exception: short links. If you explicitly enable the short link feature, a copy of the stash is stored on the shortener service for at most 7 days. Agents can also manage a stash library that lives locally in your browser’s storage.local and never leaves your machine (see Agents & MCP).

Link Security

Shared links are designed for security:

Self-contained: All data encoded in the link itself
No decryption keys: Anyone with the link can view it
Expiry enforcement: Links automatically become inaccessible
HTTPS only: All communications use encryption

Third-Party Services

Minimal Third-Party Dependencies

Stash avoids third-party services beyond anonymous telemetry:

CDN only: Static assets served from CDN
Telemetry only: The only external API calls are the anonymous aggregate counters described above (Cloudflare Analytics Engine for the extension/shortener, PostHog for the web viewer) — no other external calls during normal use
No authentication: No OAuth or external identity providers
No advertising: No ad networks or marketing pixels

Open Source

The entire project is open source:

Code transparency: All source code available for inspection
Community review: Anyone can verify security practices
No hidden features: What you see is what you get

User Controls

Complete User Control

You have full control over your data:

Manual sharing: You choose what to share and with whom
No auto-sharing: No automatic or unexpected sharing
Settings control: You configure expiry and other preferences
No backup: No data is backed up or stored anywhere

Extension Permissions

Stash requests minimal permissions:

Tab access: Only to read URLs and titles of selected tabs
Clipboard access: Only to copy share links
Notifications: Only to show status messages
No sensitive permissions: No access to passwords, history, or bookmarks

Recipient Privacy

Viewer Privacy

People who view your shared links have privacy too:

No individual tracking: Viewers aren’t tracked individually — only anonymous aggregate counters (e.g. a stash view happened) are recorded
No collection: No personal information from viewers
Temporary access: Links expire automatically

Mobile Compatibility

Shared links work on any device without compromising privacy:

No apps needed: Works in any browser
No installation: No required downloads or setup
No accounts: No registration to view links

Legal Compliance

Privacy Policy

For complete legal details, see our full Privacy Policy.

Terms of Service

For usage terms, see our Terms.

Open Source License

Stash is licensed under AGPL-3.0—free to use, modify, and distribute.

Common Privacy Questions

Q: Does Stash collect any user data? A: Stash processes everything locally. The only data leaving your device is anonymous aggregate counters (an event name and coarse dimensions) — never URLs, titles, tags, notes, or an identifier tied to you.

Q: Are my browsing habits tracked? A: No. Stash only sees the tabs you explicitly choose to share.

Q: How do you make money? A: Stash is free and open source. There’s no business model that involves data collection.

Q: Can you see who shares what? A: No. We don’t have servers that could track this information.

Stash exists because privacy matters. We believe sharing information should be simple, fast, and private by design.