An AI sea companion that never leaves your phone.
Nudii is a virtual nudibranch with a personality of its own — powered by a custom fine-tune of Google's Gemma 4 that runs entirely on your iPhone. No chat servers. No account. What you tell your nudii stays between the two of you.
Be the first to know when Nudii launches.
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Waitlist emails are handled by Formspree for this website only. The app itself keeps your conversations on your device.
The promise
What happens in the tank, stays in the tank.
Most AI companions send every word you type to a server. Nudii runs its language model on your iPhone, so the conversation physically cannot leave.
No chat servers
Conversations are generated and stored on your phone. We don't run servers that could read them — there is nothing to leak, sell, or subpoena.
No account, ever
No sign-up, no login, no profile. Open the app, hatch your egg, start talking. Your nudii knows your name because you told it — not because a database does.
No ads or tracking
No advertising SDKs, no analytics backend, no third-party trackers. The business model is the app itself — not your attention or your data.
How it works
Four steps to a small ocean friendship.
No tutorials, no waiting rooms. You're talking to your new companion within a minute of opening the app.
Hatch — instantly
Pick one of two free species, tap your egg the moment you're ready, and name a companion that feels personal from the first minute. No warming timers.
Talk, care, and play
Conversations, feeding, cleaning, Reef Arcade games, and optional HealthKit activity all shape how your nudii responds and what it remembers.
Watch them become
Six life phases, from Egg to Mythic to a final farewell. Visible growth starts on day one — and Mythic can only ever be earned, never bought.
Keep it all on your iPhone
The AI model and every memory live on your device. That's why Nudii needs newer hardware and more space than a typical pet app — and why it's private.
What makes a nudii
A companion that actually remembers you.
Built on real marine biology and real on-device AI — not a chatbot wearing a cute skin.
On-device AI
Nudii ships its own companion-voice fine-tune of Google's Gemma 4, running locally on iPhone 15 Pro or later. Chats are generated on your phone — never routed through Nudii servers.
Long-term memory
Your nudii remembers what you've talked about and brings it up naturally — your dog's name, the exam you were dreading, the good news. All of it stored locally on your phone.
Genuine evolution
Six phases — Egg, Veliger, Juvenile, Adult, Mythic, Departed — and each one changes the relationship, not just the artwork. Mythic must be earned. It can't be bought.
Rare mood days
About once a week your nudii wakes up different — Philosophical, Extra Playful, Mysteriously Quiet, or Glowing. It colors every interaction for that full day.
Care that counts
Feed, clean, tuck in, and play together. Grant optional HealthKit access and your real-world steps and workouts earn your nudii a daily bonus — read-only, never uploaded.
A theme song per species
Every species has its own original music — Latin pop for the Spanish Dancer, dreamy synths for the Opalescent. All tracks are original and copyright-free.
Species
Eight real nudibranchs. Eight personalities.
Each species is modeled on a real animal, and the biology shapes the personality — how they talk, what they love, how they grow. Two are free; six are one-time unlocks. Hover or tap to preview the earned Mythic form.
Spanish Shawl
Violet body, orange cerata. Fiery and expressive.
Anna's Chromodoris
Electric blue, orange rhinophores. Bold and inquisitive.
Opalescent
Iridescent stripes, glowing tips. Dreamy and quiet. $1.99
Four-Color
Purple, white, orange, black. Proud and eccentric. $1.99
Sea Bunny
Fluffy white, ear-like rhinophores. Playful and warm. $2.99
Blue Dragon
Pelagic blue and silver wings. Wandering and wild. $4.99
Spanish Dancer
Massive, crimson, a true swimmer. Passionate and dramatic. $3.99
Black Nembrotha
Black body, emerald crests. Brooding and deeply loyal. $2.99
The lifecycle
Fast first growth. A bond that deepens for months.
Your nudii changes visibly in the first days, then settles into a long, slow arc. Mythic cannot be purchased — it has to be earned. And when the farewell comes, it doesn't have to be the end.
Egg
Tap to hatch · instant
Veliger
Day 1–7 · baby talk
Juvenile
Day 7–30 · curious
Adult
Day 30–75 · full bloom
Mythic ✦
Day 75+ · earned only
Departed
One final farewell
The Reef Arcade
Six tiny games, inside the tank.
Playing together is part of caring. The Reef Arcade is a fully rebuilt set of six pick-up-and-play games — no ads, no energy meters, just you and your nudii.
Coral Stacker
Stack the reef, piece by careful piece.
Anemone Pop
Quick taps, perfect timing, zero stings.
Jelly Drift
Weave through a glowing bloom.
Shell Shine
Buff dull shells to a pearl finish.
Echo Reef
The reef sings. Sing it back.
Plankton Bloom
Chase the glow before it fades.
Aquariums
Seven homes. One comes free.
Give your nudii a habitat that suits its temperament. Each environment has its own light, mood, and atmosphere.
Pricing
Free to start. Deeper if you want it.
No ads. No attention tricks. No dark patterns. A full companion for free, and honest prices for more.
Starter
Free
Everything you need to hatch, raise, and love a nudii — with no time limit.
- Full lifecycle, Egg → Mythic → Departed
- Unlimited AI conversations
- Up to 50 long-term memories
- 2 starter species (Spanish Shawl & Anna's Chromodoris)
- All care mechanics + the Reef Arcade
- HealthKit activity bonuses
Subscription
Deep Diver
For those who want their nudii to remember everything and linger longer in its prime.
- Unlimited long-term memory — your nudii remembers everything
- Sea Bunny species unlocked while subscribed
- Coral Reef habitat unlocked while subscribed
- Revival Power — ongoing access to bring back a departed nudii
- Mythic extension — stay in the Mythic phase longer
- If you unsubscribe, every memory already learned stays intact
Or $24.99/year — save 47%
One-time
Add-ons
Optional extras — none required to enjoy a full Nudii life.
- Premium species, $1.99–$4.99
- Aquarium environments, $1.99–$2.99
- Decorations and special foods, from $0.99
- Depth Vaccine — 30 days of sickness immunity
- Single Revive ($1.99) on the death screen
- Stage Boost ($4.99) — Mythic excluded
FAQ
Honest answers to fair questions.
An AI pet that runs offline on your phone is an unusual thing. These are the questions we'd ask too.
Why does Nudii need an iPhone 15 Pro or later?
How big is the app, really?
Is everything completely offline?
Can I get a departed nudii back?
What happens to my nudii's memories if I stop subscribing?
Can I restore purchases after reinstalling the app?
Is Nudii a wellness or therapy app?
Be first in the water.
Nudii is coming to the App Store. Join the waitlist and we'll send exactly one email — the day it launches.
✓ You're on the list. See you in the deep.