Observed arrival · 2026-10-22
Siflo: an outdoor group messenger that relays offline
A free app for outdoor groups to send messages, preset signals, and SOS alerts—even when mobile coverage is absent.
○Open
⊠Login
$Paid
†Ads
✦Pretty
●Pro
◎Niche
◉Human
⚑Risk
ƒJS
- For
- Canyon, climbing, caving, and mountaineering groups
- Worth noticing
- Delayed signals arrive silently if they may be stale; SOS repeats every minute and can include an authorized location.
Field notes
The page illustrates its relay system with a canyoning example: one member reports a stuck rope, and phones pass the message to people ahead or below. It also distinguishes receipt from confirmation that a person has seen a signal, and says unreceived signals are retried automatically. The site describes its internet relays as unable to read the encrypted messages they forward.
Observed signals
Read the marks
Editorial observations of this landing page, not a rating.
○OpenPublic substance visible
✦PrettyNotable craft visible
●ProPolished or operationally mature
◎NicheUnusually specific use
One card from the complete issue