Converge

Real-time websocket chat server with SQLite/Postgres persistence and a built-in TUI client.

Features

• Multi-room websocket chat with join/leave events
• Message persistence in SQLite with history retrieval
• Room and user listing
• Configurable limits and timeouts
• CRDT utilities (OR-Set, LWW register)
• TUI client for local testing and demos

Requirements

• Go 1.25+

Run the server

CONVERGE_DB_PATH=converge.db CONVERGE_JWT_SECRET=dev-secret go run ./cmd/server

By default, the server listens on 0.0.0.0:8080. You can change this using PORT, CONVERGE_HOST, or CONVERGE_ADDR.

On startup, the server will log its local network IP, making it easy to connect from other devices: 2026/03/04 00:58:05 Network access: http://192.168.1.5:8080

Postgres:

CONVERGE_DB_ADAPTER=postgres CONVERGE_DB_DSN="postgres://user:pass@localhost:5432/converge?sslmode=disable" CONVERGE_JWT_SECRET=dev-secret go run ./cmd/server

Health check:

curl http://<server-ip>:8080/health

Websocket URL:

ws://<server-ip>:8080/ws?room=lobby

Quick Start Scripts

For convenience, you can use the provided scripts in the scripts/ directory:

• Start Server: ./scripts/start_server.sh
• Demo Client: ./scripts/demo_client.sh [user_id] [display_name] [server_url]

Example:

# In one terminal
./scripts/start_server.sh

# In another terminal
./scripts/demo_client.sh alice "Alice" ws://192.168.1.5:8080/ws

Authentication:

• Send Authorization: Bearer <jwt>
• Token must include user_id or sub
• Optional display_name or name for stored display name

Run the TUI client

go run ./cmd/client -server ws://localhost:8080/ws -room lobby -token "$JWT_TOKEN"

TUI commands

• /join room
• /rooms
• /users [room]
• /history [limit]
• /quit

CRDT over WebSocket

• OR-Set add

{ "type": "crdt_orset_add", "room": "lobby", "doc": "tags", "body": "alpha" }

• OR-Set values

{ "type": "crdt_orset_values", "room": "lobby", "doc": "tags" }

• LWW set/get

{ "type": "crdt_lww_set", "room": "lobby", "doc": "topic", "body": "Hello" }
{ "type": "crdt_lww_get", "room": "lobby", "doc": "topic" }

Protocol

Client → Server

• Send message

{ "type": "message", "body": "hello" }

• Join room

{ "type": "join", "room": "dev" }

• List rooms

{ "type": "rooms" }

• List users

{ "type": "users", "room": "dev" }

• Fetch history

{ "type": "history", "room": "dev", "limit": 50 }

Server → Client

• Welcome

{ "type": "welcome", "room": "lobby", "user_id": "user-123", "display_name": "Alice", "timestamp": "..." }
  "type": "welcome",

- System event

```json
{
  "type": "system",
  "room": "lobby",
  "body": "shayy joined",
  "timestamp": "..."
}

• Rooms list

{ "type": "rooms", "rooms": ["lobby", "dev"], "timestamp": "..." }

• Users list

{
  "type": "users",
  "room": "lobby",
  "users": ["user-123", "user-456"],
  "timestamp": "..."
}

• History

{
  "type": "history",
  "room": "lobby",
  "history": [{ "user_id": "user-123", "display_name": "Alice", "body": "hi" }],
  "timestamp": "..."
}

• Error

{ "type": "error", "body": "message too large", "timestamp": "..." }

Configuration

Env Var	Description	Default
PORT	HTTP listen port	8080
CONVERGE_HOST	HTTP listen host	0.0.0.0
CONVERGE_ADDR	Full listen address (override)	empty
CONVERGE_DB_ADAPTER	sqlite or postgres	sqlite
CONVERGE_DB_PATH	SQLite file path	converge.db
CONVERGE_DB_DSN	Postgres connection string	empty
CONVERGE_ALLOWED_ORIGINS	Comma-separated origins or *	empty (allow all)
CONVERGE_MAX_MESSAGE_BYTES	Max websocket frame size	65536
CONVERGE_MAX_BODY_LENGTH	Max chat message length	2000
CONVERGE_MAX_ROOM_LENGTH	Max room name length	64
CONVERGE_MAX_USER_LENGTH	Max user name length	64
CONVERGE_HISTORY_LIMIT	Max history limit	200
CONVERGE_SEND_BUFFER	Per-client send buffer size	16
CONVERGE_SAVE_BUFFER	Persist queue size	256
CONVERGE_STORE_TIMEOUT	Store operation timeout	2s
CONVERGE_WRITE_WAIT	Websocket write deadline	10s
CONVERGE_PONG_WAIT	Websocket pong wait	60s
CONVERGE_PING_PERIOD	Websocket ping period	54s
CONVERGE_READ_TIMEOUT	HTTP read timeout	10s
CONVERGE_WRITE_TIMEOUT	HTTP write timeout	10s
CONVERGE_IDLE_TIMEOUT	HTTP idle timeout	60s
CONVERGE_JWT_SECRET	HMAC secret for JWT	empty
CONVERGE_JWT_ISSUER	JWT issuer	empty
CONVERGE_JWT_AUDIENCE	JWT audience	empty

Tests

go test ./...

Use as a package

store, err := chat.NewSQLiteStore("converge.db")
if err != nil {
    panic(err)
}
defer store.Close()

hub := chat.NewHubWithOptions(store, chat.Options{
    JWTSecret: "dev-secret",
})
go hub.Run()

http.HandleFunc("/ws", hub.HandleWS)

Postgres adapter:

store, err := chat.NewPostgresStore("postgres://user:pass@localhost:5432/converge?sslmode=disable")
if err != nil {
    panic(err)
}
defer store.Close()

hub := chat.NewHubWithOptions(store, chat.Options{
    JWTSecret: "dev-secret",
})
go hub.Run()

CRDT

setA := crdt.NewORSet[string]("node-a")
setA.Add("alpha")

setB := crdt.NewORSet[string]("node-b")
setB.Add("beta")

setA.Merge(setB)

reg := crdt.NewLWWRegister("hello", time.Now().UTC(), "node-a")
reg.Set("world", time.Now().UTC(), "node-b")

Contributors

Contributing

• Read CONTRIBUTING.md for setup and PR guidelines
• See CODE_OF_CONDUCT.md for community standards

License

MIT. See LICENSE.