About
Sendline is a purpose-built iOS companion app for rock climbers, designed to solve real problems at the gym and crag. At its core, Sendline offers walkie-talkie-style push-to-talk audio sessions over local WiFi using Apple's MultipeerConnectivity framework — no internet required during sessions. This means you can communicate hands-free with your crew while on the wall without relying on cellular data. Beyond communication, Sendline acts as a personal climbing log. Athletes can record every send, attempt, and project, tracking grades, route types, and long-term progress through a personal route library. The app also includes a social layer where users can add friends via QR code, view their active sessions, and start group climbs together. Smart integrations elevate the experience: Apple Music automatically ducks when someone transmits audio, keeping your playlist uninterrupted. A Live Activity widget surfaces session status directly on the Dynamic Island and Lock Screen, so you always know who's talking without touching your phone. Gym Detection intelligently identifies nearby climbing venues to set session context automatically. Sendline is privacy-focused — audio is never recorded or stored, location is only used while the app is open, and user data is never sold. It's the go-to tool for gym rats, outdoor climbers, and anyone who wants to stay connected with their climbing community.
Key Features
- Live Push-to-Talk: Walkie-talkie style audio sessions over local WiFi using Apple's MultipeerConnectivity — no internet required, fully hands-free while you climb.
- Route Tracking: Log every send, attempt, and project with grades and route types. Build a personal climbing library and track progress over time.
- Climbing Social Layer: Add friends by QR code, see their live sessions, and start group climbing sessions together in real time.
- Music Ducking: Apple Music automatically lowers volume when someone transmits audio, so your playlist and your conversations coexist seamlessly.
- Gym Detection & Live Activity Widget: Automatically detects nearby gyms and crags for session context, and surfaces session status on the Dynamic Island and Lock Screen.
Use Cases
- Coordinating hands-free with climbing partners at the gym during active sessions without needing to pick up a phone.
- Logging personal climbing progress — tracking sends, attempts, grades, and route types over weeks and months.
- Organizing group climbing sessions where multiple friends can communicate in real time over a shared push-to-talk channel.
- Discovering nearby climbing gyms automatically and setting session context without manual input.
- Staying socially connected with your regular climbing crew through shared session visibility and friend activity feeds.
Pros
- Works Offline for Core Features: Push-to-talk sessions run entirely over local WiFi with no internet dependency, making it reliable in gyms with spotty cell service.
- Strong Privacy Stance: Audio is never recorded or stored on servers, location is only accessed while the app is in use, and user data is never sold to third parties.
- Deep iOS Integration: Live Activity on Dynamic Island, Apple Music ducking, and MultipeerConnectivity make it feel like a native, polished iOS experience.
Cons
- iOS Exclusive: Currently only available on the App Store, excluding Android users and potentially limiting group adoption if not everyone has an iPhone.
- Requires Local WiFi for Push-to-Talk: The signature push-to-talk feature depends on all users being on the same local network, which may not always be available at outdoor crags.
Frequently Asked Questions
Does Sendline require an internet connection?
Push-to-talk sessions work entirely over local WiFi with no internet required. An internet connection is only needed for account sync and authentication.
Is my audio recorded or stored?
No. Audio is transmitted directly between devices over your local network and is never recorded or stored on Sendline's servers.
How do I add friends on Sendline?
You can add friends by scanning their QR code within the app. Once connected, you can see their sessions and start group climbs together.
How does Gym Detection work?
Sendline uses your approximate location (only while the app is open) to detect nearby climbing gyms and crags, automatically setting context for your session without manual entry.
Is Sendline free to use?
Sendline is available on the App Store. Pricing details are available on the app listing, and the core companion features are accessible upon download.
