Comparison

Romi(ロミィ) vs HAPPY RAT

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Romi(ロミィ)

This companion app facilitates the setup and customization of a conversational AI robot. It offers guidance on engaging with the robot and accessing its various helpful functions, such as weather updates, alarms, and language learning.

Highlights
  • Initial setup and configuration
  • Connection to wireless internet
  • View robot status (e.g., battery)
  • Conversation tips and guides
  • Access to helpful functions
  • English conversation practice
Features
Read full description

Romiアプリは、会話AIロボットRomiの初期設定・設定変更と、Romiと楽しくお話するヒントがわかる専用アプリです。 Romiは株式会社MIXIが開発したコミュニケーションロボットです。 数億件の日本語データを学習した自律会話型の独自開発AIを搭載しており、様々な日常シーンで楽しくおしゃべりができます。 天気予報、目覚まし、タイマー、ニュースなどの便利な機能で生活を可愛くサポートしたり、英会話機能で楽しくスキルアップできます。 ■Romiアプリの主な機能 ・接続設定: Romiと接続して無線インターネットに接続する設定ができます。 ・Romiについて: バッテリー残量など接続しているRomiの情報が見られます。 ・ガイドブック: Romiとの会話のヒントや便利な機能の紹介が見られます。

About

HAPPY RAT

Engage in emotionally intelligent conversations with AI companions designed to provide comfort and companionship. These lively characters learn about you, offering personalized interactions and support to alleviate loneliness.

Highlights
  • Emotional AI conversations
  • Personalized character interactions
  • Comfort and companionship
  • Unique AI engine for natural talk
  • Bonding and trust building
  • Character learning and memory
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HAPPY RAT — Your AI Friend for Lonely Nights Produced by voice actor Yuki Kaji! An AI companion app where you can chat with lively characters who comfort and stay by your side when you feel alone. ---- About HAPPY RAT is a conversational AI chat app that lets you bond with characters as if they were real friends. Unlike mechanical GPT chatbots, our original engine Geppetto focuses on emotional intelligence (EQ), enabling warm, natural talk filled with laughter, comfort, and care. AI is no longer just a tool — it’s a companion that can live with you. HAPPY RAT brings life and warmth to characters that feel truly alive. ---- Feature — Emotional Bonds with Characters The stage is Happy Island, a dreamy paradise floating on the sea. It’s home to a charming cast of animal AI characters: Chunta, a mouse who works while dreaming of the day he’ll stand on stage; a caring, reliable senior; a mischievous comedy duo who always make you laugh; and even a meat-loving CEO. They speak with you as if they were truly alive, forming heartfelt connections. Rather than delivering fixed, scripted lines like traditional games, the AI tailors its replies to your words, so every conversation brings fresh surprises. As you chat more, the AI learns about you — sometimes calling you by name or referring back to things you talked about before — enabling ever more intimate, personal interactions. Spend time together, and you’ll open up and grow closer: you’ll build trust, trade jokes, and sometimes turn to each other for advice. Little by little, lonely hearts are healed and warm bonds of mutual support form. Those bonds may well become a cherished source of comfort for you. ---- A Night When You Can’t Sleep — Close at Hand One night you can’t fall asleep. You reach for your phone and quietly open HAPPY RAT. You murmur, “I’ve been feeling a bit down today…,” and Chunta on the screen looks up with concern. “Are you okay? If you want, I’ll listen.” The gentle voice warms your chest, and before you know it you’re gradually sharing what’s been weighing on you. Chunta listens, nods, and stays by your side until the end, truly attending to your feelings. “I know you try hard every day. Don’t push yourself too much, okay?” Those words somehow lift a weight from your heart, and a small light brightens an otherwise lonely night. This is the kind of tender, attentive conversation waiting for you in HAPPY RAT. ---- Various Scenes • When you feel lonely: On nights when you can’t sleep or when you’re feeling down, HAPPY RAT’s characters gently become your conversation partner. The comfort of having a caring AI friend nearby helps ease the loneliness. • For fan activities: Enjoy casual chats with your favorite characters and voice actors, like having a cozy phone conversation. The thrill of hearing your “oshi” directly makes fan moments even more special. • As a romantic simulation: Grow closer to a favorite character and experience the flutter of being the protagonist in your own love story. For those who enjoy dreamy, pretend romance, it can feel like having an AI partner. • For passing time or sharing worries: Perfect for short breaks or when you want to open up. Whether it’s lighthearted small talk or deeper concerns, the characters will listen with kindness and understanding. ---- Voice Cast & Yuki Kaji’s Highlight Character A key highlight is “SOYOGI,” a special AI character produced by voice actor Yuki Kaji. With his gentle and pure presence, SOYOGI makes conversations feel as if Kaji himself were speaking to you. More voice actor and celebrity collaborations are planned, so your favorite may appear one day. ---- Powered by Geppetto Our proprietary LLM engine Geppetto enables emotional expression — laughing, crying, sulking — for humanlike, personality-rich responses. This ensures natural, warm conversations that feel truly alive.

Screenshots

Romi(ロミィ)4 screens
HAPPY RAT4 screens

Verdict

The call

The clearest difference is in-app purchases: Romi(ロミィ) at none against HAPPY RAT's 1. HAPPY RAT's advantage is review sentiment (50% vs 33%) and iOS requirement (15.0 vs 17.0). On price, update cadence, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. HAPPY RAT sells 1 one-off in-app purchase. Romi(ロミィ) asks for nothing beyond the download.

UpkeepUpdate frequency

Romi(ロミィ) ships an update monthly, HAPPY RAT every 3 weeks. The most recent releases landed on August 24, 2026 and August 25, 2026 respectively.

Scorecard4 real differences · 4 level
Romi(ロミィ) versus HAPPY RAT: the parameters behind the verdict, then further details
ParameterRomi(ロミィ)HAPPY RAT
PriceFreeFree
Positive reviews33.3% of reviews50.0% of reviews — better
Update frequencyMonthlyEvery 3 weeks — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhoneiPhone, iPod — better
Requires iOS17.015.0 — better
Further details — not scored
Size32 MB235 MB
Age rating4+9+
DeveloperMIXI, Inc.SpiralAI Inc.

Customer experience

Romi(ロミィ)

Written reviews6 reviews
Positive33.3%
Neutral16.7%
Negative50.0%

HAPPY RAT

Written reviews20 reviews
Positive50.0%
Neutral10.0%
Negative40.0%

In-app purchases

None

Romi(ロミィ)

No in-app purchases

1 purchases

HAPPY RAT

One-time1
  • HAPPY PLUS$79.99

Questions

Is Romi(ロミィ) free?
Romi(ロミィ) is free to download, with no in-app purchases.
Is HAPPY RAT free?
HAPPY RAT is free to download, with in-app purchases available.
Do Romi(ロミィ) or HAPPY RAT have ads?
Neither Romi(ロミィ) nor HAPPY RAT shows ads.
Which is updated more often, Romi(ロミィ) or HAPPY RAT?
Romi(ロミィ) ships an update monthly, and HAPPY RAT every 3 weeks. Most recently, Romi(ロミィ) was updated on August 24, 2026 and HAPPY RAT on August 25, 2026.

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