Discourse is a modern, open-source discussion platform built for the next decade of the Internet. It functions as a mailing list, discussion forum, and long-form chat room, designed from the ground up to address the challenges of community management and online discussion.

Discourse is written in Ruby on Rails with an Ember.js frontend. It runs inside Docker containers, which simplifies deployment but creates opacity when deviating from the standard configuration. The platform emphasizes civilized discussion through features like trust levels, flagging systems, and moderation tools.

Key Characteristics:

• Container-based deployment via Docker
• Built-in PostgreSQL and Redis
• Real-time updates via WebSockets
• Plugin architecture for extensibility
• Comprehensive backup/restore functionality

Discourse ships as a monolithic Docker container containing:

• PostgreSQL database
• Redis for caching and background jobs
• Sidekiq for job processing
• Nginx (internal) for request handling
• Ruby on Rails application server

The container exposes ports for HTTP/HTTPS traffic and handles TLS termination internally by default. However, production deployments frequently place Discourse behind a reverse proxy for flexibility in certificate management, load balancing, or multi-application hosting.

This section documents installation on a fresh Ubuntu server with backup restoration and nginx reverse proxy configuration.

• Fresh Ubuntu Server installation (24.04 LTS recommended)
• Root or sudo access
• Existing Discourse backup file (.tar.gz) if restoring
• Domain name with DNS A record pointed to server IP
• SMTP credentials for outbound email

sudo -s
apt-get update && apt-get install -y git

git clone https://github.com/discourse/discourse_docker.git /var/discourse
cd /var/discourse
chmod 700 containers

Before running the setup script, create the container configuration. This step is critical—configuring after initial build requires a full rebuild.

Create /var/discourse/containers/app.yml with reverse proxy settings:

Comment out SSL templates:

templates:
  - "templates/postgres.template.yml"
  - "templates/redis.template.yml"
  - "templates/web.template.yml"
  - "templates/web.ratelimited.template.yml"
  ## SSL templates - COMMENTED OUT for reverse proxy setup
  # - "templates/web.ssl.template.yml"
  # - "templates/web.letsencrypt.ssl.template.yml"

Modify port exposure:

expose:
  - "8080:80"   # expose container port 80 on host port 8080
  # - "443:443" # https - commented out

<WRAP important> The 8080:80 mapping is not well-documented. The reverse proxy (nginx) handles TLS termination and forwards plaintext HTTP to port 8080. </WRAP>

./discourse-setup --skip-connection-test

The setup wizard prompts for configuration values:

<WRAP tip> The build process takes 5-15 minutes depending on hardware. </WRAP>

If restoring from an existing Discourse instance:

Transfer backup file to server:

scp -P 22 discourse-backup.tar.gz user@server:/var/discourse/shared/standalone/backups/default/

<WRAP info> Adjust the port (-P), username, and hostname to match your environment. Do NOT change the name of the file, as it is metadata necessary for the restore. </WRAP>

Restore via Admin Panel:

1. Access Discourse at http://server-ip:8080 (or domain if DNS configured)
2. Navigate to Admin → Backups
3. Locate the uploaded backup file
4. Click Restore and confirm

The restoration restarts Discourse and may take several minutes depending on backup size.

apt-get install -y nginx

Create site configuration at /etc/nginx/sites-available/forum.example.com:

server {
    listen 80;
    server_name forum.example.com;
 
    location / {
        proxy_pass http://localhost:8080;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Host $host;
 
        # WebSocket support (required for Discourse)
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
 
        # Timeouts
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;
 
        # Buffering
        proxy_buffering off;
        proxy_redirect off;
    }
 
    client_max_body_size 10m;
}

Required headers for Discourse:

• X-Forwarded-For and X-Forwarded-Host - Discourse uses these for client IP detection
• WebSocket headers - Real-time updates require Upgrade and Connection headers
• proxy_buffering off - Prevents response buffering issues

Enable the configuration:

rm /etc/nginx/sites-enabled/default
ln -s /etc/nginx/sites-available/forum.example.com /etc/nginx/sites-enabled/
nginx -t
systemctl reload nginx

snap install --classic certbot
certbot

Certbot automatically:

• Detects the nginx configuration
• Prompts for domain selection
• Generates Let's Encrypt certificates
• Modifies nginx for HTTPS
• Configures automatic renewal

Reload nginx after certificate installation:

systemctl reload nginx

Key environment variables in app.yml:

After modifying app.yml:

cd /var/discourse
./launcher rebuild app

# Enter container shell
./launcher enter app
 
# View logs
./launcher logs app
 
# Stop/start container
./launcher stop app
./launcher start app
 
# Full rebuild
./launcher rebuild app

Backups can be configured in Admin → Backups → Settings:

• Enable automatic backups
• Set retention period
• Configure S3 upload (optional)

• Verify default site removed: ls /etc/nginx/sites-enabled/
• Confirm symlink exists: ls -la /etc/nginx/sites-enabled/forum.example.com
• Test configuration: nginx -t
• Reload: systemctl reload nginx

• Run nginx test with sudo: sudo nginx -t
• Check for configs referencing non-existent certificates
• Ensure only HTTP config exists before running certbot

• Verify file location: /var/discourse/shared/standalone/backups/default/
• Check permissions: ls -la /var/discourse/shared/standalone/backups/default/
• Confirm filename ends in .tar.gz

• Port flag is capital -P (not lowercase -p)
• Syntax: scp -P <port> <source> <user>@<host>:<destination>

<WRAP center round important 60%> AUTO-GENERATED DOCUMENTATION

This section was automatically generated and is subject to change upon human review. Last updated: 2026-01-19 </WRAP>

• List channels: GET /chat/api/channels
• Get specific channel: GET /chat/api/channels/{channel_id}
• Send message: POST /chat/api/channels/{channel_id}/messages
• List messages: GET /chat/api/channels/{channel_id}/messages

All API requests require the following headers:

Api-Key: {your_api_key}
Api-Username: {username}
Content-Type: application/json

Available webhook triggers include:

• Chat message created
• Chat message edited
• Chat message trashed
• Chat message restored
• Post events (for forum integration)
• User events (login/logout/created)

Avatar URLs are provided in the avatar_template field of user objects in API responses.

{
  "user": {
    "id": 2,
    "username": "Chelsea",
    "name": "Chelsea Lee ᶘ ᵒᴥᵒᶅ",
    "avatar_template": "/user_avatar/meant2be.me/chelsea/{size}/3_2.png"
  }
}

Pattern:

{base_url}{avatar_template with {size} replaced}

Example:

https://baseurl.tld/user_avatar/baseurl.tld/username/48/3_2.png

Supported sizes: 20, 25, 32, 45, 48, 60, 90, 120, 135, 240, 360, 480

Recommended for Discord: 128 or 256

def get_avatar_url(user_obj, size=48):
    """Extract and construct full avatar URL from Discourse user object"""
    template = user_obj['avatar_template']
    avatar_path = template.replace('{size}', str(size))
    return f"https://meant2be.me{avatar_path}"
 
# Usage:
avatar_url = get_avatar_url(message['user'], size=128)

Discourse → Discord (via webhooks):

1. Webhook events trigger on chat message actions
2. Webhook receiver endpoints process incoming events
3. Forward to Discord via webhook or bot API

Discord → Discourse (via API):

1. Discord bot listens for message events
2. POST to /chat/api/channels/{channel_id}/messages
3. Payload: {“message”: “text content”}

• Message ID mapping: Track Discourse ↔ Discord message IDs to prevent echo loops
• User mapping: Map Discourse usernames to Discord user representations
• Avatar sync: Use extracted avatar URLs for Discord webhooks
• Category filtering: Configure webhooks for specific categories/channels
• Loop prevention: Maintain state to avoid infinite message echoes between platforms

{
  "messages": [
    {
      "id": 77045,
      "message": ":eyes:",
      "created_at": "2025-12-23T00:30:23Z",
      "chat_channel_id": 1,
      "user": {
        "id": 2,
        "username": "Chelsea",
        "name": "Chelsea Lee ᶘ ᵒᴥᵒᶅ",
        "avatar_template": "/user_avatar/baseurl.tld/chelsea/{size}/3_2.png",
        "moderator": true,
        "admin": true,
        "staff": true
      }
    }
  ],
  "meta": {
    "can_load_more_future": false,
    "can_load_more_past": false
  }
}

• Discourse Meta - Official community
• GitHub Repository
• Docker Repository

• SyncBot