OSHI for Festivals — Find Your Friends When the Network Is Jammed

OSHI is a free, open-source, end-to-end encrypted messenger for iOS and Android that uses Bluetooth and Wi-Fi mesh networking to send messages without Internet or cellular service. OSHI does not require a phone number, email address, or account.

Every festival-goer knows the moment: full bars, and nothing sends. Fifty thousand phones on three towers means the network is technically up and practically dead. OSHI ignores the towers. With the app open, your group's phones find each other over Bluetooth and Wi-Fi and pass messages directly, and everyone else's OSHI phones in the crowd quietly relay for you. Here is how to make it work on the day.

What works in a crowd

• Group chat with your crew. "Meet at the left tower, 9pm" reaches everyone in mesh range, relayed across up to five phones. Text is small and travels furthest.
• Live location. Share it in the group and the "which tent?" problem disappears. It works with GPS alone; no data is needed.
• Photos and voice notes. When you are close together they transfer over Wi-Fi Direct, phone to phone, fast.
• Offline map of the site. Download the region beforehand; OSHI's OpenStreetMap data usually includes the grounds, the car parks and the town.
• Catch-up when the network breathes. Any time one phone gets a usable connection, everything queued syncs, including to friends who stayed home.

Realistic range in a crowd

Bodies absorb 2.4 GHz radio. In a dense standing crowd, expect 20–40 m per Bluetooth hop rather than the 100 m you get in an empty field. The mesh compensates: the more OSHI phones between you and your friend, the better, and every phone in the chain only needs to be within range of the next. Across a large arena the message will get there, but it may take a minute rather than a second, because store-and-forward waits for phones to drift into range. Send early, keep it short.

Battery through a three-day weekend

Bluetooth Low Energy scanning is cheap; the screen is what drains a phone. OSHI keeps Wi-Fi Direct off until a photo is actually transferring. Practical tips: lower brightness, keep the app open rather than reopening it every minute (iOS throttles background Bluetooth, so an open app relays far better), turn off the cellular radio entirely if the network is hopeless (a phone hunting for signal burns more than the mesh does), and share a power bank within the group. One phone kept alive as the crew's relay is worth more than five at 3 %.

Set-up checklist (do this at home)

1. Everyone installs OSHI: App Store on iPhone, APK from this site on Android. Mixed groups are fine; the mesh works across both.
2. Add each other by QR code and create the group. Name it after the festival so it is easy to find.
3. Download the map region.
4. One airplane-mode test in the living room. Send a message, share location, send a photo.
5. Agree a fallback meeting point anyway. Radio is radio.

Privacy at an event

OSHI needs no phone number, so joining a stranger's group chat at a camp does not hand out your number, and nothing you send over the mesh touches a server. Messages are end-to-end encrypted, so relaying strangers see only ciphertext. View-once media exists for photos you would rather not have forwarded.

Alternatives

OSHI is an alternative to Bridgefy, Briar, Meshtastic and bitchat for offline communication, and to Signal for private messaging. At a festival specifically, bitchat's public local channel is a fun way to talk to strangers nearby, and Bridgefy's Broadcast does the same, though Bridgefy needs Internet on first launch, so install it before the gates. The best offline messenger comparison has the details.

Frequently asked questions