Blue Client — Privacy Policy
This policy is not a substitute for legal advice. If you have specific compliance obligations (GDPR, CCPA, APPI, etc.) you are responsible for reviewing this document against them before deciding whether to use the Software.
1. Who we are
The Blue Client project ("we"). Contact: the project's Discord server. We are not a registered legal entity, and we do not currently sell anything or charge for any part of the Software.
2. What data the client processes
When you run Blue Client, it processes the following data locally on your machine:
| Item | Source | Purpose |
|---|---|---|
| Minecraft username + UUID | Microsoft account auth | Display name, multiplayer connect |
| Microsoft access/refresh tokens | Microsoft account auth | Multiplayer auth. Stored locally in auth.json with restricted file permissions |
| Settings file | Your edits | Persist game preferences, stored locally |
| Crash logs | The client, on a crash | Saved locally to ~/.blue/crashes/; never sent anywhere automatically |
Your Microsoft tokens never leave your machine except to talk to Microsoft (to log in) and to the Minecraft server you choose to join. We do not operate any server that receives, stores, or processes this data — there is no license check, account system, or telemetry backend behind the Software.
3. Optional Discord Rich Presence
If you enable the "Discord RPC" mod (off by default), the client sends your current activity (e.g. "Playing on <server>") to your own, already-running local Discord client over Discord's local IPC. This is the same mechanism any game with Discord Rich Presence uses. It only reaches Discord's servers if you have Discord open, and what happens to it after that is governed by Discord's own privacy policy. Disabling the mod stops this immediately.
4. Mojang's client.jar
On first launch (if client.jar isn't already present), the client downloads
it directly from Mojang's official servers
(piston-meta.mojang.com / piston-data.mojang.com). This is a
standard, unauthenticated HTTPS request — Mojang sees the request the way any web server
sees any download, per their own privacy policy. We do not proxy, log, or see this
request ourselves.
5. If you report a bug on Discord
If you use the /bug command in our Discord server, whatever you type (and
any crash log you choose to attach) is sent to Discord and visible to our moderators in
a private thread. Discord's handling of that data is governed by their own
privacy policy.
We do not pull that data out into any system of our own.
6. What we don't do
- We do not operate a license server, account system, or hardware-fingerprinting of any kind.
- We do not use crash-reporting services (e.g. Sentry) — crash logs stay on your machine unless you choose to share one with us.
- We do not sell or share your data with advertisers, data brokers, or any third party for marketing purposes — we have no data of yours to sell in the first place.
- We do not currently process any payments; there is no purchase or billing data to collect. If that changes in the future, this policy will be updated and you'll be asked to accept the new version before continuing.
7. Your rights
Because essentially all of the data described above lives on your own machine, exercising
your rights (access, correction, deletion) is usually as simple as editing or deleting the
relevant local file (auth.json, your settings file, or the
~/.blue/ directory). For anything you've shared with us directly (e.g. in a
Discord bug report), contact us through the channels in section 1 and we'll act within 30
days.
8. Security
Microsoft tokens are written to disk with restricted file permissions (owner-only on Unix-like systems). We use TLS for all network requests the client makes (Microsoft auth, Mojang's servers, the Minecraft server you connect to). There is no server-side system of ours in this picture to secure, because there isn't one.
9. Children
The Software is not directed at children under 13. We do not knowingly collect data from anyone under 13 — and per section 2, we don't operate infrastructure that would let us collect it even if we wanted to.
10. Changes to this policy
Material changes are signalled by updating the "last updated" date at the top of this document. The client will re-prompt you to accept the terms again if the underlying usage terms change materially.
11. Complaints
If you believe we have mishandled your data, please contact us first so we can fix it. You retain the right to lodge a complaint with the data-protection authority in your jurisdiction (in Japan, this is the Personal Information Protection Commission, ppc.go.jp/en).