On-device AI · Android beta

Email AI that stays
on your phone.

RAI Inbox runs powerful AI directly on your device — drafting replies, summarizing threads, and managing your inbox without sending anything to the cloud unless you ask it to.

Download APK See how it works
Free, no signup Android 7.0+ latest
RAI Inbox AI illustration
v1.2
Latest build
13
Languages
3
Email providers
100%
On-device option
Features

Your inbox, your data,
your phone.

Every feature is built to work whether you're online or off, with or without the cloud. Pick what fits your day.

Voice Commands

"Hey RAI" — hands-free email, on-device.

Wake the assistant with your voice and reply, search, summarize, or navigate without touching your phone. Wake word and speech detection run locally.

  • Always-listening wake word, fully offline
  • Reply, archive, search by voice
  • Choose local or cloud transcription per command
"Hey RAI, reply that I'll be there at three"
Processed on-device
AI Smart Compose

Drafts written in your voice, not a chatbot's.

RAI reads the thread, learns your signature style, and writes replies that sound like you — formatted as proper HTML, ready to send or edit.

  • Reply, expand, or shorten with one tap
  • Auto-detects recipient formality
  • Personalized signature inserted automatically
Tokim@aermob.com
SubjectRe: Q2 launch sync

Hi Kim,

Yep, Thursday at 3pm works. I'll send the deck twenty minutes ahead so we can stay focused on the rollout timeline.

Talk soon, Jeff

Multi-Account

One inbox. Every account. Color-coded.

Gmail, Exchange (EWS), and any IMAP server. Add as many accounts as you want and switch between them with a single tap — or read them all together.

  • OAuth for Gmail, modern auth for Exchange
  • Per-account signatures, colors, notifications
  • Threaded view across all accounts
All
Personal
Work
Side
M
Maya Hong
Photos from the trip 📸
9:42
K
Kim @ Aermob
Re: Q2 launch sync
9:18
S
Substack Digest
3 new posts you might like
8:30
Smart Boxes

AI sorts the noise so you only see the signal.

Newsletters, receipts, cold pitches, and notifications get auto-categorized into smart boxes. Bulk unsubscribe, batch archive, and never lose an important thread again.

  • Auto-detected newsletters with one-tap unsubscribe
  • Cold email filter, receipts folder, and more
  • Custom rules from natural language
Newsletters
Receipts
Cold
Updates
NEWS
Stratechery — Weekly
Unsubscribe
NEWS
Morning Brew Daily
Unsubscribe
RCPT
Stripe — Invoice #5821
Archive
COLD
Outreach Bot — Demo?
Block
13 Languages

Speaks the language your inbox does.

Full localization with system language auto-detection. RAI's AI replies in the language of the email it received — even if your phone is set to something different.

  • 13 UI languages, more on the way
  • AI auto-detects email language and matches
  • Right-to-left support for Arabic and Hebrew
🇬🇧EN
🇹🇷TR
🇩🇪DE
🇫🇷FR
🇪🇸ES
🇮🇹IT
🇯🇵JA
🇰🇷KO
🇨🇳ZH
🇸🇦AR
🇮🇳HI
🇵🇹PT
Undo Send

Send confidently. Undo if you blink.

Every message gets a 30-second escape hatch before it actually leaves your phone. Catch typos, second thoughts, or the wrong recipient before they hit the wire.

  • 30-second undo window on every send
  • Drafts auto-save as you type
  • Smart recipient warnings before send
Email sent
to Kim @ Aermob
30 seconds to change your mind
Platforms

Built for Android.
Coming everywhere.

RAI Inbox started on Android because that's where on-device AI got real first. iOS and Web are next.

Android

Beta available now. Android 7.0 and up. Direct APK, no Play Store required.

iOS

SwiftUI build in progress. Same on-device privacy story. Sign up for the waitlist.

Web

A web companion is in the works. Use RAI from any browser with full feature parity.

FAQ

Questions, answered.

Privacy, providers, the cloud — here's what people ask most.

Does RAI send my emails to the cloud? +
By default, the on-device AI handles everything — replies, summaries, categorization — without leaving your phone. You can opt in to cloud models (OpenAI, Anthropic, Gemini) when you want more power for a specific task. The toggle is per-action, not all-or-nothing.
Which email providers work with RAI? +
Gmail (via OAuth), Microsoft Exchange Server (EWS), and any standard IMAP/SMTP server. Outlook.com via Microsoft Graph is in active development.
What on-device model does RAI use? +
A customized Liquid foundation model, tuned for email tasks like replies, summarization, and categorization. The on-device AI landscape is evolving fast, so we continuously evaluate and swap in newer, better local models as they ship — you get the upgrades automatically with each update.
Why isn't this on the Play Store? +
We're in open beta. Direct APK distribution lets us iterate fast and gives users the latest build immediately. Play Store listing is on the roadmap for the stable 2.0 release.
Is it free? Will it stay free? +
The core app is free and will stay free. A future RAI Pro tier will add advanced cloud AI quotas, premium models, and team features for power users who want them.
Changelog

Shipped recently.

We push updates often. Here's what's new.

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Take your inbox
back from the cloud.

Free, no signup, no telemetry. Install the APK and you're three taps from a smarter inbox.

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