SDLC (Software Development Life Cycle) is a way to structure software work so it’s repeatable and auditable—from planning and requirements through delivery and maintenance. Teams use SDLC to reduce risk, manage complexity, and improve the quality of releases over time.
This pillar explains the core SDLC ideas and links out to practical cluster pages: phases, models, tools, documentation, security, and common best practices.
Key Takeaways #
- SDLC is a framework, not a rigid rule: adapt phases and gates to your team size and risk level.
- Quality is built in: testing, reviews, and security checks should be part of the lifecycle.
- Documentation improves speed: clear requirements and design notes reduce rework.
- Tooling supports discipline: CI/CD, issue tracking, and templates make practices easy to follow.
- Measure outcomes: use metrics (defects, lead time, reliability) to iterate on the process.
What is SDLC? #
SDLC describes the stages a product goes through: requirements → design → implementation → testing → deployment → maintenance. Different organizations name phases differently, but the goal is consistent: make work visible and reduce surprises.
Good SDLC does not mean more paperwork—it means the right level of structure for the risk you’re managing (user impact, compliance, security, uptime).
Why SDLC Matters #
- Predictability: stakeholders understand what “done” means at each stage.
- Quality and security: defects are cheaper to catch earlier; security can be integrated from day one.
- Knowledge transfer: documentation and standards reduce bus factor and onboarding time.
- Continuous improvement: post-release feedback feeds into better planning and prioritization.
Step-by-Step: Apply SDLC Without Overhead #
- Define your phases and what must be true to move forward (acceptance criteria).
- Standardize artifacts: issue templates, PR templates, design notes, release checklists.
- Automate quality gates: CI tests, linting, security scans, and reviews.
- Ship in small batches: reduce risk with incremental delivery and rollback plans.
- Review outcomes: run retrospectives and use metrics to improve the next cycle.
Comparison Table #
| Option | Best For | Pros | Cons |
|---|---|---|---|
| Waterfall SDLC | Fixed scope, compliance-heavy projects | Clear phases, predictable docs | Slow feedback, hard to change mid-stream |
| Agile SDLC | Products with changing requirements | Fast feedback, iterative | Requires discipline to avoid chaos |
| Spiral/Iterative | High-risk systems | Risk-driven iterations | More process complexity |
Common Mistakes #
- Skipping requirements validation — unclear scope causes rework and churn.
- Testing too late — late bug discovery increases cost and delays releases.
- Treating security as a final checklist — integrate security and threat thinking across the lifecycle.