What you are running

Plainwire 2.0 is a realtime chat server built around Erlang/OTP, Cowboy, PostgreSQL, WebSocket, and WebRTC. Redis can accelerate short-lived realtime state. ScyllaDB can become the high-volume message timeline after an explicit migration. TURN provides a relay path for calls when direct peer-to-peer connectivity fails.

A normal small installation does not need every optional component. Start with the smallest topology that meets your needs, then add services because measurements justify them.

Internet
   |
   v
Caddy or nginx :443
   |
   v
Plainwire :8080
   |---------------- PostgreSQL :5432    required relational authority
   |---------------- Redis :6379         optional realtime accelerator
   |---------------- ScyllaDB :9042      optional timeline backend
   |
   +---- HTTPS to approved integrations and TURN credential providers

Browsers <---------------- WebRTC ----------------> Browsers
                  \        TURN        /
                   \------ relay ------/

What each component owns#

Component	Responsibility	Can Plainwire run without it?
Plainwire	API, WebSocket, authorization, message logic, RTC signaling, admin plane	No
PostgreSQL	Accounts, servers, channels, membership, roles, permissions, integration config, and default message storage	No
Redis	Distributed rate gates, node-aware presence, hot recent-message cache	Yes
ScyllaDB	High-volume message timeline and event history when enabled	Yes
Reverse proxy	Public TLS termination and HTTP routing	Public deployments should use one
TURN	Media relay for difficult NAT and firewall cases	Calls become less reliable without it

Storage rule#

Keep one authority for each kind of data.

PostgreSQL is relational truth.
Redis is disposable acceleration.
Scylla is ordered history at scale when the message backend is switched.
Object or filesystem storage holds upload bytes.

If Redis is empty after a restart, Plainwire should recover. If PostgreSQL is lost without a backup, the installation is not recoverable. If Scylla is the active message backend, it becomes part of the backup and recovery plan.

Safe first deployment#

For a first public instance, use PostgreSQL, Redis, a reverse proxy, and a TURN service. Leave PLAINWIRE_MESSAGE_BACKEND=postgres and PLAINWIRE_SCYLLA_ENABLED=false until you have a reason to operate Scylla.

Next: Quick start.