How to Self-Host Flarum: Modern Forum Software 2026

TL;DR

Flarum (MIT, ~15K GitHub stars, PHP) is modern forum software that's fast, beautiful, and extensible. Unlike Discourse (which requires 2GB+ RAM and significant setup), Flarum is lightweight (~100MB RAM), loads instantly, and has a polished UI out of the box. It supports Markdown, mentions, tags, real-time updates, SSO, and a rich extension ecosystem. Perfect for product communities, support forums, or hobbyist groups.

Key Takeaways

Flarum: MIT, ~15K stars, PHP — modern, lightweight forum
Fast: PHP + MySQL backend loads in milliseconds — feels like a SPA
Extensions: 200+ community extensions — polls, OAuth, reactions, SEO, themes
Real-time: Live updates — new posts appear without page refresh
Markdown: Full Markdown editor with preview
SSO: OAuth2, LDAP, SAML via extensions — integrate with Authentik/Authelia

Flarum vs Discourse vs phpBB vs NodeBB

Feature	Flarum	Discourse	phpBB	NodeBB
RAM usage	~100MB	~2GB+	~100MB	~300MB
Language	PHP	Ruby	PHP	Node.js
UI quality	Excellent	Excellent	Dated	Good
Setup time	10 min	30+ min	20 min	15 min
Extensions	200+	150+	1000+	300+
Real-time	Yes	Yes	No	Yes
SEO	Good (+ extensions)	Excellent	Good	Good
Email-in	No	Yes	No	Yes
Self-hosted	Yes	Yes	Yes	Yes
Price	Free	Free	Free	Free

Part 1: Docker Setup

# docker-compose.yml
services:
  flarum:
    image: crazymax/flarum:latest
    container_name: flarum
    restart: unless-stopped
    ports:
      - "8888:8000"
    volumes:
      - flarum_data:/data
    environment:
      TZ: America/Los_Angeles
      FLARUM_BASE_URL: https://forum.yourdomain.com
      FLARUM_FORUM_TITLE: "Your Community"
      FLARUM_API_PATH: api
      FLARUM_BASE_PATH: /

      # Database:
      DB_HOST: db
      DB_NAME: flarum
      DB_USER: flarum
      DB_PASSWORD: "${DB_PASSWORD}"
      DB_PREFIX: flarum_

      # Admin account (first run):
      FLARUM_ADMIN_USER: admin
      FLARUM_ADMIN_PASSWORD: "${ADMIN_PASSWORD}"
      FLARUM_ADMIN_MAIL: admin@yourdomain.com

      # SMTP:
      FLARUM_MAIL_FROM: forum@yourdomain.com
      FLARUM_MAIL_DRIVER: smtp
      FLARUM_MAIL_HOST: mail.yourdomain.com
      FLARUM_MAIL_PORT: 587
      FLARUM_MAIL_USERNAME: forum@yourdomain.com
      FLARUM_MAIL_PASSWORD: "${MAIL_PASSWORD}"
      FLARUM_MAIL_ENCRYPTION: tls

    depends_on:
      - db

  db:
    image: mariadb:11
    restart: unless-stopped
    volumes:
      - flarum_db:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: "${DB_ROOT_PASSWORD}"
      MYSQL_DATABASE: flarum
      MYSQL_USER: flarum
      MYSQL_PASSWORD: "${DB_PASSWORD}"

volumes:
  flarum_data:
  flarum_db:

echo "DB_PASSWORD=$(openssl rand -base64 24)" >> .env
echo "DB_ROOT_PASSWORD=$(openssl rand -base64 24)" >> .env
echo "ADMIN_PASSWORD=$(openssl rand -base64 16)" >> .env

docker compose up -d

Part 2: HTTPS with Caddy

forum.yourdomain.com {
    reverse_proxy localhost:8888
}

Part 3: Forum Configuration

Admin panel

Access: https://forum.yourdomain.com/admin

Essential settings

Basics:
  - Forum title
  - Forum description
  - Welcome banner (shown to new users)
  - Default homepage: All Discussions / Tags

Appearance:
  - Logo and favicon upload
  - Primary color
  - Dark mode (via extension)
  - Custom header HTML
  - Custom CSS

Email:
  - SMTP configuration
  - Notification settings

Create tags (categories)

Admin → Tags:
  Primary tags (categories):
    📢 Announcements
    💬 General
    ❓ Support
    💡 Feature Requests
    🐛 Bug Reports
    🎉 Show & Tell

  Secondary tags (cross-cutting):
    Solved
    Pinned
    FAQ

Part 4: Extensions

Install extensions

# Enter the container:
docker exec -it flarum sh

# Install an extension via Composer:
composer require fof/oauth
composer require fof/polls
composer require fof/reactions
composer require flarum/markdown
composer require flarum/mentions
composer require flarum/tags
composer require flarum/sticky
composer require flarum/lock
composer require flarum/flags

Essential extensions

Extension	What it does
`flarum/markdown`	Markdown formatting in posts
`flarum/mentions`	@mention users and quote posts
`flarum/tags`	Category system with primary/secondary tags
`flarum/sticky`	Pin discussions to the top
`flarum/lock`	Lock discussions from new replies
`flarum/flags`	User-reported content moderation
`flarum/approval`	Require approval for new posts
`flarum/subscriptions`	Follow/unfollow discussions

Popular community extensions

Extension	What it does
`fof/oauth`	Login with GitHub, Google, Discord, etc.
`fof/polls`	Create polls in discussions
`fof/reactions`	Like/reaction buttons on posts
`fof/best-answer`	Mark answers as "Best Answer" (Q&A)
`fof/drafts`	Save draft posts
`fof/upload`	File and image uploads
`fof/sitemap`	Generate XML sitemap for SEO
`fof/nightmode`	Dark mode toggle
`fof/user-bio`	User bio/about section
`v17development/flarum-seo`	Advanced SEO meta tags
`askvortsov/flarum-categories`	Traditional category layout
`clarkwinkelmann/flarum-ext-emojionearea`	Emoji picker

Part 5: Moderation

Moderation tools

Flag posts: Users can report content → moderators review
Suspend users: Temporary ban with reason and duration
Delete/hide posts: Remove or soft-delete content
Lock discussions: Prevent new replies
Merge discussions: Combine duplicate threads
Move discussions: Change tags/categories

Set up moderation team

Admin → Users → [user] → Groups → Add to "Mods" group

Group permissions (Admin → Permissions):
  Mods can:
    - Edit & delete posts
    - Lock & sticky discussions
    - Approve posts
    - View user IP addresses
    - Suspend users

Part 6: SSO with Authentik

Install OAuth extension:

docker exec -it flarum composer require fof/oauth

Admin → OAuth → Add provider → Custom OAuth
Configure:
- Client ID: from Authentik
- Client Secret: from Authentik
- Authorize URL: https://auth.yourdomain.com/application/o/authorize/
- Token URL: https://auth.yourdomain.com/application/o/token/
- Userinfo URL: https://auth.yourdomain.com/application/o/userinfo/

Users can now log in with their Authentik account.

Part 7: SEO Optimization

Install SEO extensions

docker exec -it flarum composer require v17development/flarum-seo
docker exec -it flarum composer require fof/sitemap

SEO configuration

Admin → SEO:
  - Meta description: auto-generated from discussion content
  - Open Graph tags: share previews on social media
  - Twitter Cards: rich previews when sharing links
  - Structured data: JSON-LD for search engines
  - Canonical URLs: prevent duplicate content

Sitemap

https://forum.yourdomain.com/sitemap.xml

Submit to Google Search Console for indexing.

Part 8: REST API

# Flarum has a JSON:API compliant REST API

BASE="https://forum.yourdomain.com/api"

# List discussions:
curl "$BASE/discussions" | jq '.data[].attributes.title'

# Get a discussion:
curl "$BASE/discussions/1" | jq '.data.attributes'

# Create a discussion (authenticated):
curl -X POST "$BASE/discussions" \
  -H "Authorization: Token YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "data": {
      "type": "discussions",
      "attributes": {
        "title": "Welcome to our community!",
        "content": "This is our new forum. Introduce yourself!"
      },
      "relationships": {
        "tags": {
          "data": [{"type": "tags", "id": "1"}]
        }
      }
    }
  }'

Maintenance

# Update Flarum:
docker exec -it flarum composer update --prefer-dist --no-dev -a
docker exec -it flarum php flarum migrate
docker exec -it flarum php flarum cache:clear

# Update container:
docker compose pull
docker compose up -d

# Backup:
docker exec flarum-db-1 mysqldump -u flarum -p"$DB_PASSWORD" flarum \
  | gzip > flarum-db-$(date +%Y%m%d).sql.gz

tar -czf flarum-data-$(date +%Y%m%d).tar.gz \
  $(docker volume inspect flarum_flarum_data --format '{{.Mountpoint}}')

# Logs:
docker compose logs -f flarum

Why Self-Host Flarum?

The case for self-hosting Flarum comes down to three practical factors: data ownership, cost at scale, and operational control.

Data ownership is the fundamental argument. When you use a SaaS version of any tool, your data lives on someone else's infrastructure subject to their terms of service, their security practices, and their business continuity. If the vendor raises prices, gets acquired, changes API limits, or shuts down, you're left scrambling. Self-hosting Flarum means your data and configuration stay on infrastructure you control — whether that's a VPS, a bare metal server, or a home lab.

Cost at scale matters once you move beyond individual use. Most SaaS equivalents charge per user or per data volume. A self-hosted instance on a $10-20/month VPS typically costs less than per-user SaaS pricing for teams of five or more — and the cost doesn't scale linearly with usage. One well-configured server handles dozens of users for a flat monthly fee.

Operational control is the third factor. The Docker Compose configuration above exposes every setting that commercial equivalents often hide behind enterprise plans: custom networking, environment variables, storage backends, and authentication integrations. You decide when to update, how to configure backups, and what access controls to apply.

The honest tradeoff: you're responsible for updates, backups, and availability. For teams running any production workloads, this is familiar territory. For individuals, the learning curve is real but the tooling (Docker, Caddy, automated backups) is well-documented and widely supported.

Server Requirements and Sizing

Before deploying Flarum, assess your server capacity against expected workload.

Minimum viable setup: A 1 vCPU, 1GB RAM VPS with 20GB SSD is sufficient for personal use or small teams. Most consumer VPS providers — Hetzner, DigitalOcean, Linode, Vultr — offer machines in this range for $5-10/month. Hetzner offers excellent price-to-performance for European and US regions.

Recommended production setup: 2 vCPUs with 4GB RAM and 40GB SSD handles most medium deployments without resource contention. This gives Flarum headroom for background tasks, caching, and concurrent users while leaving capacity for other services on the same host.

Storage planning: The Docker volumes in this docker-compose.yml store all persistent Flarum data. Estimate your storage growth rate early — for data-intensive tools, budget for 3-5x your initial estimate. Hetzner Cloud and Vultr both support online volume resizing without stopping your instance.

Operating system: Any modern 64-bit Linux distribution works. Ubuntu 22.04 LTS and Debian 12 are the most commonly tested configurations. Ensure Docker Engine 24.0+ and Docker Compose v2 are installed — verify with docker --version and docker compose version. Avoid Docker Desktop on production Linux servers; it adds virtualization overhead and behaves differently from Docker Engine in ways that cause subtle networking issues.

Network: Only ports 80 and 443 need to be publicly accessible when running behind a reverse proxy. Internal service ports should be bound to localhost only. A minimal UFW firewall that blocks all inbound traffic except SSH, HTTP, and HTTPS is the single most effective security measure for a self-hosted server.

Backup and Disaster Recovery

Running Flarum without a tested backup strategy is an unacceptable availability risk. Docker volumes are not automatically backed up — if you delete a volume or the host fails, data is gone with no recovery path.

What to back up: The named Docker volumes containing Flarum's data (database files, user uploads, application state), your docker-compose.yml and any customized configuration files, and .env files containing secrets.

Backup approach: For simple setups, stop the container, archive the volume contents, then restart. For production environments where stopping causes disruption, use filesystem snapshots or database dump commands (PostgreSQL pg_dump, SQLite .backup, MySQL mysqldump) that produce consistent backups without downtime.

For a complete automated backup workflow that ships snapshots to S3-compatible object storage, see the Restic + Rclone backup guide. Restic handles deduplication and encryption; Rclone handles multi-destination uploads. The same setup works for any Docker volume.

Backup cadence: Daily backups to remote storage are a reasonable baseline for actively used tools. Use a 30-day retention window minimum — long enough to recover from mistakes discovered weeks later. For critical data, extend to 90 days and use a secondary destination.

Restore testing: A backup that has never been restored is a backup you cannot trust. Once a month, restore your Flarum backup to a separate Docker Compose stack on different ports and verify the data is intact. This catches silent backup failures, script errors, and volume permission issues before they matter in a real recovery.

Security Hardening

Self-hosting means you are responsible for Flarum's security posture. The Docker Compose setup provides a functional base; production deployments need additional hardening.

Always use a reverse proxy: Never expose Flarum's internal port directly to the internet. The docker-compose.yml binds to localhost; Caddy or Nginx provides HTTPS termination. Direct HTTP access transmits credentials in plaintext. A reverse proxy also centralizes TLS management, rate limiting, and access logging.

Strong credentials: Change default passwords immediately after first login. For secrets in docker-compose environment variables, generate random values with openssl rand -base64 32 rather than reusing existing passwords.

Firewall configuration:

ufw default deny incoming
ufw allow 22/tcp
ufw allow 80/tcp
ufw allow 443/tcp
ufw enable

Internal service ports (databases, admin panels, internal APIs) should only be reachable from localhost or the Docker network, never directly from the internet.

Network isolation: Docker Compose named networks keep Flarum's services isolated from other containers on the same host. Database containers should not share networks with containers that don't need direct database access.

VPN access for sensitive services: For internal-only tools, restricting access to a VPN adds a strong second layer. Headscale is an open source Tailscale control server that puts your self-hosted stack behind a WireGuard mesh, eliminating public internet exposure for internal tools.

Update discipline: Subscribe to Flarum's GitHub releases page to receive security advisory notifications. Schedule a monthly maintenance window to pull updated images. Running outdated container images is the most common cause of self-hosted service compromises.

Troubleshooting Common Issues

Container exits immediately or won't start

Check logs first — they almost always explain the failure:

docker compose logs -f flarum

Common causes: a missing required environment variable, a port already in use, or a volume permission error. Port conflicts appear as bind: address already in use. Find the conflicting process with ss -tlpn | grep PORT and either stop it or change Flarum's port mapping in docker-compose.yml.

Cannot reach the web interface

Work through this checklist:

Confirm the container is running: docker compose ps
Test locally on the server: curl -I http://localhost:PORT
If local access works but external doesn't, check your firewall: ufw status
If using a reverse proxy, verify it's running and the config is valid: caddy validate --config /etc/caddy/Caddyfile

Permission errors on volume mounts

Some containers run as a non-root user. If the Docker volume is owned by root, the container process cannot write to it. Find the volume's host path with docker volume inspect VOLUME_NAME, check the tool's documentation for its expected UID, and apply correct ownership:

chown -R 1000:1000 /var/lib/docker/volumes/your_volume/_data

High resource usage over time

Memory or CPU growing continuously usually indicates unconfigured log rotation, an unbound cache, or accumulated data needing pruning. Check current usage with docker stats flarum. Add resource limits in docker-compose.yml to prevent one container from starving others. For ongoing visibility into resource trends, deploy Prometheus + Grafana or Netdata.

Data disappears after container restart

Data stored in the container's writable layer — rather than a named volume — is lost when the container is removed or recreated. This happens when the volume mount path in docker-compose.yml doesn't match where the application writes data. Verify mount paths against the tool's documentation and correct the mapping. Named volumes persist across container removal; only docker compose down -v deletes them.

Keeping Flarum Updated

Flarum follows a regular release cadence. Staying current matters for security patches and compatibility. The update process with Docker Compose is straightforward:

docker compose pull          # Download updated images
docker compose up -d         # Restart with new images
docker image prune -f        # Remove old image layers (optional)

Read the changelog before major version updates. Some releases include database migrations or breaking configuration changes. For major version bumps, test in a staging environment first — run a copy of the service on different ports with the same volume data to validate the migration before touching production.

Version pinning: For stability, pin to a specific image tag in docker-compose.yml instead of latest. Update deliberately after reviewing the changelog. This trades automatic patch delivery for predictable behavior — the right call for business-critical services.

Post-update verification: After updating, confirm Flarum is functioning correctly. Most services expose a /health endpoint that returns HTTP 200 — curl it from the server or monitor it with your uptime tool.

See all open source community tools at OSSAlt.com/categories/community.

The SaaS-to-Self-Hosted Migration Guide (Free PDF)