# Software Development Life Cycle (SDLC) Confidence: high Last verified: 2026-05-22 Generation: human_only ## TL;DR SDLC is the structured process for planning, creating, testing, and deploying software. Phases: Planning → Requirements → Design → Implementation → Testing → Deployment → Maintenance. Models: Waterfall (sequential), Agile (iterative), DevOps (continuous). SDLC reduces risk, manages complexity, and ensures quality. ## Core Explanation Waterfall: phases in strict order, no going back — works for well-understood, stable requirements. Agile: iterative sprints (1-4 weeks), continuous feedback — works for evolving requirements. DevOps: extends Agile to operations, CI/CD pipelines automate build-test-deploy. Hybrid: Wagile (Waterfall for planning, Agile for execution). ## Further Reading - [Software Engineering (10th Ed, Sommerville)](undefined)