Nothing leaves without your yes.

What can be sent

Only the kinds you allow, from the launcher's first-run question or Settings → Data collection:

• Performance statistics, after each play session of a minute or more. These are the frame-time and tick-time percentiles and a 14-bucket histogram (never a recording of each frame), the peak memory, how long the game took to start and to load the world, and the settings that change performance (render and simulation distance, frame limit, VSync, fullscreen, graphics mode).
• Crash reports, when the game crashes. They hold the error, where it happened in Horizon's code, your graphics adapter and settings. They hold no log, no world, no server and no resource packs.
• Bug reports that you write and send yourself. The end of the game's log goes with one only if you add it after reading it, and lines of chat are removed first.
• Benchmark uploads of the benchmarks you run. These are shown publicly in the community results.

Each one also carries the Horizon version, the day it was made (not the time), and a description of your machine: the operating system and version, the CPU model and thread count, the memory rounded to the gigabyte, and the GPU, its driver and the graphics backend. It also carries a random install ID. The launcher makes that ID the first time you allow something; it says nothing about you and exists only so that your data can be deleted.

Never sent: your Microsoft or Minecraft account name or UUID, world names, server or LAN addresses, chat, and your user name or home folder in file paths. Before anything is kept, those are replaced with placeholders, along with e-mail and IP addresses. The server does not store the IP address requests come from.

The launcher shows exactly what would be sent: Settings → Data collection → View what would be sent, or horizon-launcher data show. Every field is listed in docs/telemetry.md.

Why

To find what is slow or crashes on which machines, and fix it. Benchmark uploads also show other players how Horizon runs on hardware like theirs. Nothing is sold, shared for advertising, or used to identify you.

On what basis

Your consent (Article 6(1)(a) of the EU's General Data Protection Regulation). It is given kind by kind, recorded on your computer with the version of the question you answered and when, and withdrawn at any time with the same switches. Withdrawing deletes what was waiting to be sent. When what is collected changes, the launcher asks again, and nothing new is sent until you answer.

Where and how long

Items wait on your computer (telemetry/ in the game folder) and are sent compressed when the launcher starts or closes, to Horizon's own server at Railway. The server keeps them for 180 days, then deletes them. What stays after that are anonymous totals per day, Horizon version, operating system, GPU maker and render distance (for example "120 sessions on macOS with Apple GPUs at render distance 12"). They hold no install ID, and groups too small to be anonymous are never shown.

Deleting your data

Settings → Data collection → Delete my data, or horizon-launcher data delete. The server deletes everything sent under your install ID, your share of the totals is recomputed, anything waiting on your computer is removed, and you get a new install ID. You can also turn everything off, or delete the telemetry/ folder.

Your rights and contact

Horizon is made by Ludovic Marie, who is responsible for this data. To ask for a copy of what was sent under your install ID, have it corrected or deleted, or ask anything about it, write through lu4ovic.com (give your install ID, shown in Settings → Data collection). You can also complain to the data protection authority where you live.

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