# FAQs
## The basics
### Do my friends need to install anything?
Only if they want to. Members can use the Phlip app (Android) or any modern browser. Only the **host** needs the app — the server is built into it.
### Does it cost anything?
Hosting and every feature are free. The only optional costs: a **domain** if you want a permanent public address (see [[Guides/Go public with Cloudflare]]), and a cosmetic **supporter pack** — themes, card finishes, Open Pitch card backs, a badge. Supporter purchases never unlock features: hosting and everything functional is free for everyone, as a founding principle.
### Is it open source?
Yes — Apache-2.0 licensed.
### Do I need an account with Phlip the company?
There is no Phlip company account. Your identity is a username + password **per server**, held by that server (your friend's phone), not by us.
## Hosting
### What can I host on?
Any Android phone running the Phlip app — a recycled spare that lives on a charger, **or your everyday phone**: hosting runs as a foreground service alongside normal use. One phone can host multiple servers. See [[Guides/Host a server on your Android phone]].
### Does the host phone need a SIM card?
No. Any internet connection works.
### What happens if the host phone is off or offline?
The server is unreachable until it's back — like a clubhouse with the lights off. All data is stored on the host, so nothing is lost and everything resumes intact. (Members' personal spaces keep working offline regardless.)
### How do people connect from outside the host's Wi-Fi?
The **Public** toggle opens a Cloudflare Tunnel from the app — either a free temporary `.trycloudflare.com` address or a permanent one on your own domain. No router setup. One public server per phone at a time. Guide: [[Guides/Go public with Cloudflare]].
### Where exactly is my data?
On the host phone, in a per-server data file. Cloudflare relays public connections but your group's content lives only on the host — and message/event content is end-to-end encrypted anyway (below).
## Security & privacy
### Is it end-to-end encrypted?
**Message and event content — yes.** Content is encrypted with AES-GCM-256 using a group key. Your personal password does the heavy lifting: the group key is wrapped for you under a key derived from your password, and the password itself is never sent over the wire — the server only ever stores a salt and a verifier. Nobody, including someone holding the join code, can read content or impersonate you without your password.
**Not everything is covered yet.** Some metadata — event time fields, display names, icons, routing information — is not yet end-to-end encrypted, and the host can see the IP of a pending join request (that's part of deciding who to admit). Extending E2E to remaining metadata is on the [[Roadmap]]. We'd rather you know the exact boundary than assume the wrong one.
### What if I forget my password?
The host removes your old membership and re-admits you with the join code. Your password is a real cryptographic key, so there's no "reset email" — there's no company to send one.
### Can someone with the join code impersonate me?
No. The join code gets you to the door; your per-user password verifier is what proves you're you. Unrecognised devices are asked for the join code *and* your password.
### Who decides who's in?
The host — every new member goes through **Approve/Deny**, and the member directory lets the host manage roles (host / admin / moderator / user / viewer) or remove people.
### What about photos?
Deliberately minimal. Chat is for coordinating plans — no photo uploads, no galleries on the server. **Memories** photos are stored only on your own device, never uploaded; sharing a memory composes a card image on your device that you choose to send.
## Other apps
### Do we all have to leave our group chat?
No. Phlip is an events planner, not a chat replacement — most groups keep chatting wherever they already do and use Phlip for the part chat is bad at: turning "we should do something" into a real plan with a time, a place and an RSVP list. You can share any event as a card image with a link, so people who never open Phlip still see the plan.
### Connecting Phlip to other chat apps
Bringing plans in and out of tools like WhatsApp and Discord automatically is planned, not built — it's on the [[Roadmap]]. For now, sharing an event card and link is the way to reach people outside a server.
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