What is STACKIT Application Load Balancer?
The STACKIT Application Load Balancer (ALB) is a managed Layer 7 load balancer that distributes HTTP/HTTPS traffic based on content: URL path (prefix or exact match), host names, HTTP headers, and query parameters. The ALB API has been generally available (GA) since January 2026. Since August 4, 2026, the ALB Web Application Firewall (ALB WAF) has also reached GA: it inspects Layer 7 traffic on a per-listener basis, is powered by the Coraza engine, and combines a managed rule set based on the OWASP Core Rule Set with a JSON abstraction for custom rules. Unlike the STACKIT Load Balancer, which operates at Layer 4 (TCP/UDP), the ALB is suited for modern microservices architectures and API gateways where routing decisions depend on request content.
Core Features
- Content-based routing: Forwarding by URL path, host name, HTTP headers, and query parameters
- TLS termination and TLS bridging: SSL/HTTPS processing at the load balancer, with optional encrypted forwarding to the backend
- Health checks: Active HTTP-based and basic TCP checks; unhealthy backends are automatically removed from the target pool
- Sticky sessions: Cookie-based session affinity for stateful applications
- Access control: IP-based access control lists (ACLs) to restrict access
- WebSocket support: For real-time applications
- High availability: Active/passive cluster on two virtual machines across multiple availability zones
- Observability: Metrics via Prometheus, logs via Loki
- Web Application Firewall (ALB WAF): GA since August 4, 2026; Coraza engine with an OWASP Core Rule Set-based rule set and custom rules, configurable via API, SDK, and Terraform provider
Typical Use Cases
Microservices routing: A single ALB routes traffic to different backend services based on URL paths (e.g. /api, /app, /static), without separate load balancers per service.
API gateways: Central entry point for multiple APIs with routing by host or path plus TLS termination.
Kubernetes ingress: Used as an ingress solution for workloads on the STACKIT Kubernetes Engine (SKE).
Stateful applications: Sticky sessions ensure that a user’s requests are consistently sent to the same backend instance.
Benefits
- GDPR-compliant: Runs on STACKIT infrastructure in EU01 (Germany) and EU02 (Austria)
- Layer 7: Content-based routing for modern application architectures
- Highly available: Redundant setup across multiple availability zones
- Centralized: One ALB can replace many individual reverse proxies
Integration with innFactory
As an official STACKIT partner, innFactory supports you with load balancer architecture: from routing rule design and TLS configuration to integration with STACKIT Kubernetes Engine and firewall services.
Typical Use Cases
Frequently Asked Questions
What is the STACKIT Application Load Balancer?
The Application Load Balancer (ALB) is a Layer 7 load balancer that distributes HTTP/HTTPS traffic based on content such as URL path, host name, HTTP headers, and query parameters. It runs as a managed service on STACKIT infrastructure in the regions EU01 (Germany) and EU02 (Austria).
How does the ALB differ from the STACKIT Load Balancer?
The STACKIT Load Balancer operates at Layer 4 (TCP/UDP) and distributes traffic regardless of content. The ALB operates at Layer 7 and enables content-based routing, for example for microservices or API gateways.
What does the Application Load Balancer cost?
Billing is usage-based (pay-per-use). Current prices are available in the STACKIT pricing calculator.
How highly available is the ALB?
Each ALB runs on two virtual machines in an active/passive cluster, distributed across multiple availability zones. Details on the contractually guaranteed availability are in the official SLA documentation.
Can the ALB be used with STACKIT Kubernetes Engine?
Yes. The ALB can be used as an ingress solution for workloads on the STACKIT Kubernetes Engine (SKE).
Does the ALB offer a Web Application Firewall (WAF)?
Yes. ALB WAF has been generally available (GA) since August 4, 2026. It is powered by the Coraza engine with a managed rule set based on the OWASP Core Rule Set and can be configured via the stable v1 API, SDK, or Terraform provider; a graphical configuration option in the STACKIT Portal is not yet available according to the documentation.
Note: All product information on this page has been compiled with care, but is provided without guarantee and may be outdated or incomplete. Cloud services evolve rapidly — features, pricing, SLAs, and availability change frequently. Authoritative and up-to-date information can only be found on the official product page of STACKIT (official documentation). This page does not represent an offer by STACKIT.
