FUTO, HeliBoard, FlorisBoard, Urik, FrankenKeys

All five keyboards in this post make the same core claim FrankenKeys makes: no network permission, verifiable on the phone. So the interesting question is not who is private. It is what each one gave up to get there, and what it asks of you in return. Everything below is from the projects' own pages as read on 2026-09-06; links at the end.

The short table

Where each one beats FrankenKeys

I will do this column first because a comparison that only flatters its author is not worth linking to.

All four are source-available and three are open source. HeliBoard and Urik are GPL-3.0, FlorisBoard is Apache 2.0. You can build them yourself and know that the binary you run is the source you read. FrankenKeys ships unobfuscated, which means you can read the shipped build, but you cannot rebuild it and the licence does not let you redistribute it. That is a weaker claim and I am not going to dress it up. Why I chose it anyway is in a separate post.

FUTO has its own offline voice engine. FrankenKeys uses Android's system recogniser, which on Android 12 and up it binds on-device explicitly. FUTO ships a recogniser of its own, and per its site the voice input "can be used with a different keyboard if it is compatible". That is more work than I have done, and it means FUTO's offline dictation does not depend on what the phone vendor shipped. FUTO also says its licence is a one-time payment, which is the same shape as the FrankenKeys Pro unlock, and I think it is the right shape.

Urik encrypts what it learns. Its privacy statement describes AES-256 encryption of learned words and clipboard history through SQLCipher, with keys in the Android Keystore, and the F-Droid listing shows biometric and fingerprint permissions for gating access. FrankenKeys keeps its learned words in app-private storage, which other apps cannot read, but it does not encrypt them at rest and does not gate them behind a fingerprint. If a phone is rooted or imaged, Urik's design holds up better than mine.

HeliBoard and FlorisBoard have communities. Issues, translations, forks, years of history. FrankenKeys has one person and a Play listing.

Where FrankenKeys is different

The feature list. Fifty key sounds synthesised in C++ rather than played from files, thirty press effects, fifteen swipe trails, ten shaders, twenty haptic profiles, thirty-one themes and a Theme Studio, all with the same empty network line. None of the four above is trying to be this, and most of their users would not want it. If you want a quiet keyboard, they are quieter.

On-device AI rewrites. Grammar, tone and clean-up through Android's own AICore where the phone supports it, and a deterministic rules engine everywhere else. Which phones have the model tier is its own post.

Thirty dictionary languages in the package. No downloads. HeliBoard supports many more languages than thirty, to be clear; the difference is that FrankenKeys ships its thirty inside the APK, so there is no dictionary fetch of any kind, through a browser or otherwise.

Glide typing without a closed library. HeliBoard's README is honest that glide typing needs "a closed source library" it cannot include. FrankenKeys swipes with its own decoder.

Which one to pick

If source you can build is the property you care about most: HeliBoard, FlorisBoard or Urik, in whatever order you rate maturity, community and encryption.

If you want offline dictation that does not depend on the phone vendor, and are happy to pay once and accept a source-first licence: FUTO.

If you want the sounds and the effects and the AI rewrite, with the same permission list, and can live with reading the binary rather than building it: FrankenKeys.

None of those is a wrong answer, and all five are better on the one axis this site is about than a keyboard that holds the network permission and asks you to read its policy.

If a maintainer of any of the four reads this and finds a line unfair, it changes. The address is at the bottom of every page.