authentik SSO: AI-Optimized Technical Reference

System Overview

What: Self-hosted open-source SSO solution replacing Okta, Auth0, Azure AD
Core Technology: Python/Django with PostgreSQL backend
Community: 18k GitHub stars, active Discord community
Cost Impact: 90% reduction vs commercial SSO ($40/month vs $375/month for 25 users)

Critical Configuration Requirements

Memory and Resource Specifications

• Minimum RAM: 2GB (system fails with 1GB - swaps to death)
• Production RAM: 4GB minimum, 8GB for multiple outposts
• Storage: 50GB minimum for logs and database growth
• CPU: 2 cores minimum for stable operation
• I/O Requirements: Decent disk I/O - PostgreSQL becomes chatty under load

Database Configuration (Critical Failure Points)

• PostgreSQL Version: 16+ required for authentik 2025.4+
• Upgrade Risk: Breaking changes in version upgrades - follow migration guide exactly
• Connection Pooling: Default settings assume development load - will fail in production
• Shared Memory: Requires tuning for larger user counts
• Backup Strategy: Essential - losing database means rebuilding from scratch

Initial Setup Gotchas

• Recovery Key: Save immediately or risk permanent lockout
• Docker Configuration: Use official compose file exactly - custom configs fail
• PostgreSQL Setup: Follow docs precisely or face connection timeouts

Protocol Support Matrix

Protocol	Implementation Quality	Configuration Difficulty	Production Readiness
OAuth2/OIDC	Excellent - plug-and-play	Easy	Production ready
SAML	Works but fiddly	High - XML attribute tweaking required	Functional with effort
LDAP	Solid	Moderate	Production ready
RADIUS	Available	Moderate	Production ready

Integration Reality Check

• OAuth2: Works out of box with Grafana, Nextcloud, GitLab
• SAML: Expect debugging time with enterprise apps that implement SAML "creatively"
• Legacy Systems: LDAP outpost handles most legacy application requirements

Cost Analysis (Real Numbers)

Solution	50 Users/Month	100 Users/Month	Self-Host Cost	Lock-in Risk
authentik	$40 (server)	$40 (server)	$40/month	None - open source
Okta	$100-750	$200-1500	N/A	High
Microsoft Entra	$300-1100	$600-2200	N/A	Very high
Auth0	$1150+	$2300+	N/A	High
Keycloak	$40 (server)	$40 (server)	$40/month	None - open source

Deployment Options

Docker Compose (Recommended < 100 users)

# Use official compose file - don't customize
wget https://goauthentik.io/docker-compose.yml
# Modify .env only for environment variables

Stability: High once running
Setup Time: Weekend project
Maintenance: 2 hours/month

Kubernetes (Production Scale)

• Use official Helm chart
• Configure ingress, storage classes, resource limits
• Default values assume unlimited resources - adjust for production
• Setup Complexity: High - requires K8s expertise

Failure Modes and Mitigation

Common Production Failures

1. Memory Exhaustion: 503 errors from swapping - increase RAM
2. PostgreSQL Connection Limits: Tune connection pooling
3. Outpost Connectivity: Fails silently - implement monitoring
4. Redis Memory Usage: Sessions accumulate - monitor and clean
5. Container Log Volume: Verbose by default - implement log rotation

Breaking Change Patterns

• Monthly Updates: Expect breaking changes
• Database Migrations: Follow upgrade procedures exactly
• SAML Configurations: May require adjustments with new versions
• API Changes: Review release notes before upgrading

Security Implementation

MFA Configuration

• Google Authenticator: Works out of box
• YubiKey/Hardware Keys: Initial setup pain, then flawless
• WebAuthn/Passkeys: Difficult initial configuration, excellent once working
• Default Flows: Cover most use cases without customization

Production Hardening

• Save recovery keys immediately
• Implement proper backup strategy
• Monitor authentication logs
• Use outpost system for distributed auth
• Configure reverse proxy correctly (Traefik/nginx)

Maintenance Requirements

Update Schedule

• Frequency: Monthly security patches
• Breaking Changes: Common - plan upgrades carefully
• Testing Required: Always test in staging first
• Downtime: Plan for authentication outages during upgrades

Monitoring Essentials

• Container logs (verbose by default)
• PostgreSQL connections and query performance
• Redis memory usage
• Outpost connectivity status
• Reverse proxy configuration health

Migration Considerations

From Commercial SSO

• OAuth2 Apps: Direct migration possible
• SAML Apps: Expect configuration adjustments
• User Data: Export/import capabilities available
• Downtime: Plan for authentication service interruption

Vendor Lock-in Escape

• Data Portability: Full control over user data and configurations
• API Access: Complete REST API for automation
• Blueprint System: Infrastructure as code capabilities
• Custom Policies: Python scripting for advanced rules

Support and Community Quality

Community Resources

• Discord: Active, helpful responses from maintainers
• GitHub Issues: Responsive maintainer engagement
• Documentation Quality: Surprisingly comprehensive and accurate
• Integration Guides: Community-contributed, verified working configs

Enterprise vs Open Source

• Open Source Limitations: None for typical deployments
• Enterprise Features: FIPS compliance, official support tickets
• Support Quality: Community support often superior to paid alternatives

Decision Criteria

Choose authentik if:

• Cost reduction priority (90% savings vs commercial)
• Self-hosting capability exists
• Open source preference
• Need protocol flexibility (OAuth2, SAML, LDAP, RADIUS)

Avoid authentik if:

• No in-house container management skills
• Zero tolerance for maintenance overhead
• Require enterprise compliance (SOC2, FedRAMP)
• Need point-and-click simplicity over cost savings

Critical Success Factors

1. Follow documentation exactly - customization causes failures
2. Plan adequate resources - 2GB RAM minimum, not optional
3. Implement proper backups - database loss = complete rebuild
4. Test upgrades in staging - breaking changes are common
5. Monitor system health - outpost failures are silent

Real-World Performance Thresholds

• User Capacity: Handles 100+ users on 4GB RAM
• Response Time: Sub-second authentication with proper resources
• Reliability: 99.9% uptime achievable with proper setup and monitoring
• Scalability: Horizontal scaling via outpost system