Gravline Privacy Policy
Last updated: November 10, 2026
Gravline is a racing game made by Complete OS LLC. It has no accounts, no ads, no purchases and no AI. Most of what it keeps stays on your device. This page lists everything that can leave it.
What stays on your device
Your racer name, credits, upgrades, weapon choices, best laps and settings are saved in your browser's storage. We can't see them unless you turn on cloud sync.
If you use tilt steering, the game reads your phone's motion sensors to steer. That reading stays on your device. In the iPhone app, vibration (haptics) and controller rumble happen on the device and send nothing.
What leaves your device, and why
- Cloud sync (only if you turn it on). Your save, including your racer name, is stored on our database so you can continue on another device. It's found using a 16-character sync code. We store only a scrambled version (a hash) of that code, not the code itself.
- Phone as a controller (only if you scan the code on the TV). The phone sends button and stick states to the TV. No name, no account, no mic, and nothing is saved on the phone. It connects directly on the same Wi-Fi; if it can't, those button presses pass through our backup server, which doesn't log or store them. Cloudflare sees IP addresses when that happens.
- Online rooms (only if you host or join). Your racer name and live race data go to the other players in your room. Devices connect directly to each other, so other players' devices can see your internet (IP) address. If a direct link can't be made, your name and race data pass through our own backup server, which runs on Cloudflare. They're encrypted on the way there and back, but the server has to read each message to pass it on. Nothing is saved or logged, and only the people in your room receive them. Cloudflare sees your IP address when this happens. A short setup message passes through our database service to connect you, and it isn't saved.
- Connection helpers (online rooms only). Google and Cloudflare run the public servers that help devices find each other. They see your IP address when you connect.
- Gameplay statistics (website only). When you play at gravline.vercel.app, the game sends a page view and a note when a race starts (track, mode and laps), with a random ID that changes every time the game opens and is never saved, so visits can't be joined up over time. No racer names, room codes or location. The App Store and Google Play apps never send these.
- Game Center (iPhone and iPad app only, if you're signed in). Your best lap on each track, your Daily race time and the achievements you earn are sent to Apple's Game Center so they show on its leaderboards. Game Center is run by Apple under Apple's privacy policy, with the nickname and settings you chose there; you can turn it off in the Settings app. Gravline never sees your Apple ID or Game Center name.
- Error reports. If the game hits an error, it sends a technical report so we can fix it, with your device and browser type. Room codes are removed, racer names aren't included and IP addresses aren't stored.
- Loading the game. Vercel hosts the game and handles your request for its pages, which includes your IP address.
Gravline has no ads and no ad tracking, and doesn't build a profile of you. We don't sell your information or share it for advertising.
Your microphone
On iPhone and in some browsers, hosting or joining a room asks for microphone permission, because on some home networks the device won't connect to another one without it. That step sends no sound, nothing is recorded, and you can refuse it and still try to connect. Gravline has no voice chat. The Android app doesn't ask for the microphone at all.
Who we use
- Vercel: hosts the game.
- Supabase: stores cloud saves and passes the room setup messages.
- Google: a connection server.
- Apple Game Center: leaderboards and achievements in the iPhone and iPad app.
- Cloudflare: a connection server, and it runs our backup server for rooms.
- Sentry: error reports.
- PostHog: gameplay statistics, website only.
How long we keep it
- Saves on your device stay until you clear them.
- A cloud save is deleted after 180 days without use. One that was written once and never updated can be deleted after 2 days.
- Sentry keeps error reports for the period its service plan sets. Vercel, Google and Cloudflare keep their own technical logs under their own policies.
Your choices
- See or delete what's on your device: clear this site's data in your browser settings, or remove the installed app and its data.
- Move your data: use Save & devices in the game to copy your save code.
- Delete a cloud save or ask a question: email us with your sync code. We can't find a save without it, because we don't know whose it is.
You can ask us to access, correct, delete or send you any information we hold about you, wherever you live, and we'll answer.
Children
Gravline is made for ages 13 and up. We don't ask for anyone's real name, email, age or location. Racer names are filtered and limited to 12 letters and numbers, and there's no text chat. If you believe a child under 13 has put personal information into a racer name or cloud save, email us and we'll delete it.
Security
Connections to the game use encryption, and cloud saves can be reached only with the sync code. Anyone who has your code can open your save, so keep it private. No system is perfectly secure.
Changes
If this policy changes, we'll update this page and the date above.
Contact
Complete OS LLC · hello@completeos.app