Stacks Privacy Policy

Effective date: September 5, 2026

This Privacy Policy describes how Stacks handles information across its two surfaces: the Stacks iOS app (with its share extension) and the Stacks Chrome extension. Stacks helps you save, organize, and revisit links.

Summary

• Stacks does not sell your data, and shows no ads.
• We collect only what the product needs: your account identity and the content you choose to save.
• You can export your data and delete your account (and all synced data) from inside the app.
• The iOS app embeds no third-party advertising or analytics SDKs. Our backend uses PostHog for product analytics (see below).

The Stacks iOS App

Information we process

• Account data — your email address and display name, provided when you sign up with email, Google, or Apple. Sign in with Apple supports Apple's private relay email.
• Saved content — links you save, titles, notes, folders, and imported items. Synced to our server so your library follows you across devices.
• Phone numbers (optional) — if you invite someone to a shared folder by phone number, we store that number so they auto-join when they sign up with it. We never send SMS ourselves — invitation messages are sent from your own device via apps you choose (Messages, WhatsApp, Mail).
• Push tokens and timezone — used to deliver notifications you opt into (e.g. the daily feed digest). Stored against your account; removed when you sign out or delete the account.
• Subscription status — whether your account has an active Stacks Premium subscription. iOS payments are handled entirely by Apple; we never see your payment details.
• Location — the map tab shows your position on-device only. Your location is never transmitted to our servers.

How saved content is processed

• AI summarization — for Premium features, the content of links you save (article text, video transcripts, captions) is sent to Anthropic (and, for audio transcription, OpenAI) to generate summaries. These providers process the content as our service providers and do not use it for advertising.
• Content retrieval — public content of links you save or creators you follow may be retrieved through Apify, our scraping service provider.
• Maps geocoding — place names found in your saved content are geocoded via OpenStreetMap's Nominatim service to power the map view. Queries contain place names only, never your identity.
• YouTube import — the optional playlist import uses YouTube API Services. By using it you agree to the YouTube Terms of Service; Google's handling of that data is described in the Google Privacy Policy. Stacks only requests read-only access and stores just the links and titles you choose to import. You can revoke Stacks' access at any time in your Google security settings.

Retention, deletion, export

• Export Data (Account tab) hands you a JSON file of everything stored for your account.
• Delete Account (Account tab) permanently deletes your account and all synced data from our servers.
• Signing out detaches this device's push token from your account.

Copyright, Content & Takedowns

Stacks is an independent product of Sprite Labs and is not affiliated with, endorsed by, or sponsored by Instagram, TikTok, YouTube, X, or any other platform whose links you save. Platform names and logos belong to their owners.

• What Stacks shows — for a link you save or a creator you follow, Stacks displays a small preview thumbnail, the title, the creator's name, and a link to the original post. Tapping a card always takes you to the original on the platform where it was published. Stacks never re-hosts or plays full third-party content.
• Summaries are ours, not theirs — summaries in Stacks are AI-generated by Stacks and are labeled as such. They are not written or endorsed by the platforms or the creators.
• Takedown requests — if you are a creator (or an authorized agent) and want content removed from Stacks' previews, email abhinavkapoor14@gmail.com with the link(s) in question and evidence of ownership. We act on valid requests promptly, normally within 72 hours, including removal of any cached preview images from our servers.
• Repeat-infringer policy — accounts that repeatedly save content in violation of others' rights after notice may be terminated.

The Stacks Chrome Extension

The extension organizes browser tabs/windows and saves your link stacks locally, with an optional user-controlled sync feature.

• Sync is opt-in. You can use the extension fully in local-only mode.
• Data is stored locally in your browser profile via chrome.storage.local; when sync is enabled, your saved stacks are also stored on your sync server account so data can sync across devices.
• Extension permissions: tabs (read/manage tabs you choose to save), storage (local stacks), identity/identity.email (separate local data per Chrome profile), bookmarks (bookmark import), notifications and alarms (reminders and background refresh), contextMenus (right-click save), and scripting with broad host access — used to read the page you explicitly save or import from (e.g. harvesting your own saved posts) and to reach your sync server. The extension does not read pages in the background or inject scripts except on your explicit action.
• Uninstalling the extension removes extension-managed local data; Delete Account + Synced Data removes remote synced data.

Analytics

Our backend sends product-usage events (e.g. sign-ins, link saves, summary generation) to PostHog, our analytics service provider, associated with your account (including your email address) so we can understand feature usage and fix problems. Events may include the hostname of sites you save from (e.g. "youtube.com"), never the full links or their content. PostHog processes this data on our behalf and does not use it for advertising. Deleting your account removes the identifying association.

Data Sharing and Selling

Stacks does not sell, rent, or share your personal data with third parties for advertising or marketing. Data is shared only with the service providers named in this policy (Anthropic, OpenAI, Apify, PostHog, and OpenStreetMap's Nominatim geocoder), solely to provide Stacks features; with Apple for iOS subscription billing; and with Stripe if you subscribe through the Chrome extension's web checkout (your card details go directly to Stripe and never touch our servers).

Security

All traffic between the apps and our servers uses HTTPS. Access tokens are short-lived; passwords are stored salted and hashed. Our backend runs on Railway with a PostgreSQL database.

Changes

We'll update this page when the policy changes and adjust the effective date above.

Contact

For privacy questions, contact: abhinavkapoor14@gmail.com