This article contains some useful notes to have on hand when using Kaerutomo, as well as an explanation of some common errors.


Once you've installed Kaerutomo, no matter your platform, please note that you must not attempt to link a Nintendo Account; this is not supported. Instead, Kaerutomo uses Kaeru Accounts to enable similar functionality, although these are implemented in a slightly different way.

With a Kaeru Account, your Kaerutomo save file is safely backed up and synchronised across your devices in the cloud, so if you switch phones or reinstall, you won't lose any of your progress. If you're entitled to access Kaerutomo Beta, you can even switch between it and Stable by simply repatching and logging in again :)

You can create and manage your Kaeru Account at - we look forwards to expanding these features as time and capacity allows.

Kaerutomo Beta and Kaeru Accounts

Access to the Kaerutomo Beta is currently available on an invite-only basis, e.g to donators and Patreon supporters, to limit numbers whilst we test new features and so as not to overwhelm the beta code. If you have not been granted access, you should not attempt to install or use the Beta version; instead, use the Stable release, which is available to the general public free of charge.

If you have recently joined our Patreon, ask a team member to enable your account for Beta usage.

Common error codes

As Kaerutomo is still in development and isn't an official Nintendo product, you may encounter some rough edges / errors whilst using it. Here is an explanation of some of the errors you might encounter:

Error codeDefinitionNotes
801-0011-0000Communication with the assets server timed out.This is fairly common as Kaerutomo directs Miitomo to pull its asset files from the Wayback Machine's archive, which can sometimes be slow or unstable.
The only solution to this is to either keep trying, or come back later. It should eventually work; patience is a virtue.
801-1150-xxxxServer error (BaaS)This indicates either a feature that has not been implemented, or a bug in the Kaerutomo server code.
801-1250-xxxxServer errorThis indicates either a feature that has not been implemented, or a bug in the Kaerutomo server code.
801-1300-xxxxService unavailableThis may appear if you're using an unpatched copy of Miitomo, or if  the Kaerutomo service is down for maintenance.
801-1450-xxxxCould not connect to serverCheck your Internet connection, or on Android, try repatching your app.
801-1900-xxxxInvalid server response contentsThis indicates an error with the response received from the Kaerutomo server and means there is a problem on our end; contact Kaeru support to let us know.
801-9000-xxxxFailed to decode server responseThe data returned from the server couldn't be decoded by Miitomo using its proprietary obfuscation cipher.
This often occurs if you're using an outdated patch, as the old endpoints are no longer serving Miitomo data; if this is the case, starting with a clean install from the Play Store / a clean APK, repatch using the latest Kaerutomo patch bundle.
If you're using the latest patch, this indicates a problem with the Kaerutomo server; contact Kaeru support to let us know.