Natsumeru

Messages that get through on weak signal and satellite. End-to-end encrypted.

Natsumeru is a messenger that always gets your message through — even on weak signals and satellite connections.

■ No "failed to send"
When the signal drops, nothing fails. Messages wait on your phone and go out automatically the moment you are connected again. You never have to resend by hand.

■ Built for weak and satellite links
Each message is tiny. Over satellite, text and stickers go first, and files up to 1 MB go too; photos and voice messages follow once you are back on a land connection. The transcript of a voice message arrives first, so the content gets through right away.

■ No signal at all? Use Bluetooth
With no network at all, you can still message a friend nearby directly over Bluetooth (one-to-one, while both of you have the chat open). Nothing goes through the server, and messages stay encrypted.

■ Natsume san, your on-device concierge
Natsume san, a black cat, is in your friend list from the start. Ask Natsume san to set timers and reminders, add events to your calendar, check the weather forecast, open a map app for directions, or explain how the app works. Natsume san also shares one Natsumeru tip a day, and sometimes just chats, with Jyanken chan dropping by.
Natsume san runs entirely on your device: what you say is never sent to us or to any AI service (only weather forecasts are fetched, directly from the Japan Meteorological Agency). Everything but the forecast works with no signal or over satellite. Natsume san speaks English or Japanese, following your app language.

■ Translate on your device
When a friend writes in another language, a small "Translate" appears under their message. Tap it to translate on your device; the original stays visible above the translation. Translations are never sent to us or to your friend. When language data is needed, it is downloaded only with your OK, over Wi-Fi or a strong mobile signal — never over satellite.

■ End-to-end encrypted
Messages, photos, files, stickers and voice messages are encrypted between devices. The server only relays them, still encrypted, and deletes them once delivered. Your chat history and friend list live only on your device.

■ Features
- One-to-one and group chats
- Edit photos before sending (crop, rotate, color, stickers, emoji, text, drawing, mosaic)
- Save received photos to your photo library (Natsume san lets you know 3 days before old photos are shrunk or removed to save space)
- Send files up to 10 MB (PDF, GPX, KML, ZIP and more), view them in the app, or share them in from other apps
- Built-in sticker packs and favorites
- Make your own stickers (photo cut-outs, text, drawing, layers, zoom in for fine detail)
- Voice messages and voice typing (both transcribed on your device)
- On-device translation of messages in other languages
- Reactions, read receipts, unsend
- Location sharing on a map (choose how often and for how long; export your track as GPX)
- Sign in to up to three accounts on one phone and switch between them
- App lock with fingerprint, face unlock or screen lock
- Earn "Natsupo" points and level up as you use the app
- Read and answer notifications on Wear OS watches
- Use it on your computer's browser too
- Encrypted backups and automatic Android backup

■ Privacy
No tracking. Your name and email address are not stored on the server. Your display name and icon go only to your friends' devices. Your chats with Natsume san and your translations never leave your device.

Satellite messaging requires a supported device and carrier. Weather forecasts cover areas in Japan. Translation works for language pairs your device supports.