ChatFix
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Privacy

Chats are personal. ChatFix is built so that only you, and people you choose to invite, can see your chat. This page explains what happens to your data.

Your file stays on your device

When you choose a WhatsApp export, your phone or computer reads it. The file itself is never uploaded and never saved. Names of the people in the chat are not sent to us. The app only sends the text of the messages, the time they were sent, and whether each one is yours or someone else's. You choose which person is you.

What we send for analysis

To find your mistakes, the app sends your messages to an AI service, together with nearby messages from the other people in the chat, so the AI understands what you meant. Those messages are used only to read your mistakes. The temporary copy kept while the chat is being analysed is erased as soon as each part is done.

What we store

  • For each mistake we found: your message, the corrected version, the explanations, and the few messages around it (up to 3 before and 2 after). Those nearby messages can be from other people in the chat. Long ones are shortened.
  • The habits (groups of mistakes) made from them.
  • Messages with no mistakes are not stored. We only keep a short one-way code for each message we checked, so that uploading the same chat again does not repeat the work. The code cannot be turned back into the message.
  • Your practice progress, which only you can see.
  • Your email address (from Google or email sign in), and the emails of people you invite.
  • Voice clips of correct sentences, so each sentence is made only once.
  • Voice notes: if you choose to include them, only the notes you choose are uploaded. They are turned into text and the audio is deleted right after. If something goes wrong, the audio is deleted within 24 hours anyway. We keep only the text of notes that have mistakes, as a correction.
  • Messages you check on the Check page are not saved unless you press Save.
  • How much you used this month and today (counts only, for your plan's limits).
  • If you have Pro: your Stripe customer and subscription ids and the subscription status. Never your card details.

We never write message text in our logs and never put it in a web address.

Who can see your chat

Only the people on the chat's member list, and only when they sign in with Google or with a link sent to the invited email. The owner can invite up to 5 people, for example a teacher or a friend. Members can see everything stored for that chat, including the nearby messages, so only invite people you trust. The demo is the one public page. It uses made-up example sentences, not real chats.

Who processes the data

  • Mistake finding: Anthropic Claude, reached through OpenRouter. We ask for providers that do not keep your data or train on it.
  • Voice notes: OpenAI speech to text. The audio is deleted right after it is turned into text.
  • Voice: OpenAI text to speech. Only a correct sentence or a habit example is sent, never the whole chat.
  • Storage and sign in: Supabase, in the EU. Access rules in the database keep chats private.
  • Hosting: Vercel.
  • Payments for Pro: Stripe. Your card details go straight to Stripe and never reach us.
  • Sign in: Google, or a one-time link and code sent by email (sent by Resend). We only get your email address, and your name if you use Google.

Cookies and tracking

We use only the cookies needed to keep you signed in and remember your settings. There are no ads and no tracking. This site is hidden from search engines.

Deleting your data

  • Delete a chat any time in its settings. This removes its mistakes, habits, practice progress, message codes and voice clips.
  • If a chat was shared with you, you can leave it in the same place.
  • Reset your practice progress in Settings.
  • Hide a single mistake from its menu if you do not want it shown.

Backups kept by our database provider can take a short time to clear after you delete something.