GrindBuddy — Privacy Policy
Last updated: August 31, 2026
GrindBuddy is a browser extension and web dashboard that helps you write replies on X (x.com) in your own writing style. This page explains what data it handles and why. Questions: lxmatulin@gmail.com.
What we collect
- Account email. Used to sign you in. Authentication is handled by Supabase; we never see or store your password.
- Your X handle. You enter it on the dashboard so the extension knows which profile is yours to import from.
- Your own public posts. When you click “Import my tweets” on your own X profile, the extension reads up to about 100 of your recent public posts and sends their text to our backend to build your “voice profile”. It does not read other people’s profiles.
- Reply context. When you click the ✨ button on a post, the visible text of that post and up to five preceding posts in the thread are sent to our backend to generate suggestions. This text is used for that request and not stored.
- Usage counts. The number of suggestions you generate per day, to enforce plan limits.
- Anonymous error counts. If the extension can’t find an element it expects on x.com, it reports a short label (e.g.
tweetText) and the extension version so we can fix it. No post content and no personal data are included.
What we do not collect
- Passwords or payment information.
- Direct messages, private posts, or drafts.
- Your browsing history or activity on sites other than x.com.
- Posts from profiles other than your own, beyond the single post (and its thread) you are actively replying to.
How your data is used
Only to generate reply suggestions that sound like you and to run your account (sign-in, plan limits). We do not sell your data, use it for advertising, or use it to train models beyond the API calls needed to produce your suggestions and voice profile.
Who it is shared with
- Supabase — hosts authentication and our database.
- Google (Gemini API) — receives the post text described above at generation time and at import time in order to return suggestions and your voice profile.
- Our hosting provider, which runs the backend that routes these requests.
We do not share your data with anyone else.
Retention and deletion
Your data is kept while your account is active. You can replace your imported posts at any time by importing again. To delete your account and all associated rows (profile, imported posts, voice profile, usage counts), email lxmatulin@gmail.com and we will remove them.
The extension
The extension runs only on x.com. It never posts, replies, likes, follows, or clicks anything on your behalf — you always review and send replies yourself. It stores only your login session locally in your browser so it can talk to our backend.
Children
GrindBuddy is not directed at children under 16.
Changes
If this policy changes, we will update this page and the date above.