Statelessness

Kind: principle

Layer: Performance Core

Record: architecture:statelessness

Severity: recommended

Scope: service, process, handler

Canonical: Ontology

A design rule that a handler keeps no request state between calls, so any instance can serve any request.

Listed in Architecture principles, after Caching and before Concurrency.

Requires

• Externalized State

Reinforces

• Horizontal Scaling
• Resilience

Enables

• Load Balancing
• Auto-Scaling

Conflicts with

• Instance Affinity
• Temporal Coupling

In tension with

• State Access Latency

Tensions

• Statelessness / State Access Latency

Violated by

• Instance-Local State

Refactored by

• Externalize Session State
• Session Management

Severity

• recommended

Category

• Scalability / Performance / Optimization

Linked from

• Computation and resource
• Separate, trade, or mitigate
• The principle architecture
• Anti-patterns
• Error Handling / Resilience
• Scalability / Performance / Optimization
• Self-Healing / Recovery / Deployment Safety
• Scalability / Performance / Optimization
• Severity levels
• The resolutions