SDLC Process Guide: Phases, Methodologies, and How to Improve Yours

SDLC—Software Development Life Cycle—is the structured process teams use to build software. Whether you follow Waterfall, Agile, or something in between, understanding SDLC phases helps you identify bottlenecks and improve your delivery process. This guide explains the modern SDLC, how to measure each phase, and where most teams get stuck.

"The SDLC isn't a process to follow—it's a lens for understanding where value gets stuck on its way to customers."

What is SDLC?

The Software Development Life Cycle (SDLC) is a framework that describes the phases software goes through from concept to retirement. Every software project follows some version of this cycle, whether explicitly or not.

The classic SDLC phases are:

1. Planning — Define goals, scope, and feasibility
2. Requirements — Gather and document what needs to be built
3. Design — Architect the solution
4. Development — Write the code
5. Testing — Verify it works correctly
6. Deployment — Release to production
7. Maintenance — Support, fix bugs, iterate

The Software Development Life Cycle

┌─────────────────────────────────────────────────────────────────┐
│                                                                 │
│   Planning → Requirements → Design → Development → Testing →   │
│                                                                 │
│                        ↓                                        │
│                                                                 │
│              ← ← ← Deployment → Maintenance → → →              │
│                        │                                        │
│                        │ (feedback loop)                        │
│                        ▼                                        │
│                   Back to Planning                              │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

SDLC Methodologies

Different methodologies implement the SDLC differently. The methodology you choose affects how work flows through these phases:

The Modern SDLC in Practice

In modern software teams, especially those practicing DevOps and continuous delivery, the SDLC phases often overlap and happen in parallel:

1. Ideation & Planning

Ideas come from customers, stakeholders, or the team. This phase includes:

• Problem definition and user research
• Feasibility assessment
• Prioritization against other work
• Rough scoping and resource allocation

Common bottleneck: Too many ideas, unclear priorities. Work sits in "planning" indefinitely.

2. Requirements & Design

Define what to build and how. Modern teams often combine these:

• User stories or PRDs (Product Requirement Documents)
• Technical design docs for complex features
• API contracts and schema definitions
• Wireframes or prototypes for UX

Common bottleneck: Over-documentation. Spending weeks on specs for features that take days to build.

3. Development

Writing code. In modern teams, this phase is highly measurable:

• Coding time (first commit to PR opened)
• PR size and complexity
• Branch lifetime
• WIP (Work in Progress) limits

Common bottleneck: Context switching. Developers juggling too many things, none making progress.

4. Code Review & Testing

Verifying quality before merging. This is where many teams lose the most time:

• Wait for review (PR sits waiting for attention)
• Review time (reviewer examining code)
• Iteration (address feedback, re-review)
• Automated testing (CI pipeline)

Common bottleneck: Review pickup time. PRs wait hours or days before anyone looks at them.

5. Deployment

Getting code to production. Modern practices minimize this phase:

• Continuous Integration (CI) — Automated builds and tests
• Continuous Deployment (CD) — Automated releases
• Feature flags — Deploy without releasing
• Canary releases — Gradual rollout

Common bottleneck: Manual deployment processes. Waiting for "deployment windows" instead of shipping when ready.

6. Monitoring & Maintenance

Post-deployment observation and iteration:

• Production monitoring and alerting
• Bug fixes and incident response
• Performance optimization
• Feature iteration based on feedback

Common bottleneck: Bug-fixing dominates. Teams spend so much time on bugs they never ship new features.

Measuring Each SDLC Phase

"You can't improve what you don't measure. But measuring the wrong things makes them worse, not better."

Here are meaningful metrics for each SDLC phase:

SDLC Process Improvement

Improving your SDLC means finding and eliminating bottlenecks. Here's a systematic approach:

Step 1: Map Your Current Flow

Document how work actually flows through your process (not how it's supposed to flow):

Example: Current SDLC Flow Analysis

Phase               Avg Time    Wait Time    % of Total
──────────────────────────────────────────────────────
Ideation            -           14 days      -
Requirements        3 days      5 days       16%
Development         4 days      1 day        10%
Code Review         1 day       3 days       8%   ← Most wait here
Testing             0.5 days    0.5 days     2%
Deployment          0.5 days    2 days       5%   ← Manual process
Maintenance         ongoing     -            -

Total Lead Time: ~33 days (14 days just waiting for review/deploy)

Step 2: Identify Biggest Bottleneck

Focus on the phase with the most wait time. In the example above, it's code review (3 days waiting) and deployment (2 days waiting).

Step 3: Apply Targeted Fixes

Step 4: Measure Impact

After implementing fixes, measure again. Did lead time decrease? Did the bottleneck move to a different phase?

SDLC Anti-Patterns

Common mistakes that slow down software delivery:

1. Big Bang Releases

Saving up changes for quarterly releases creates risk. Smaller, more frequent releases are safer and provide faster feedback.

2. Handoff Culture

When phases are owned by different teams (dev → QA → ops), handoffs create delays. Cross-functional teams that own the full cycle are faster.

3. Over-Process

Approval gates, change advisory boards, and heavyweight documentation slow teams without proportional safety benefits. Automate checks where possible.

4. Under-Investment in Automation

Manual testing, manual deployments, and manual code reviews don't scale. Every repetitive task is a candidate for automation.

5. Invisible Work in Progress

Without visibility into WIP, teams overcommit. Visualize all work in progress— not just development, but reviews waiting, deployments queued, bugs triaged.

"The goal isn't to follow the SDLC perfectly—it's to ship valuable software to users as quickly and safely as possible."

Related Guides

• DORA Metrics Guide — Industry-standard metrics for software delivery
• Deployment Frequency & Lead Time — Measuring your deployment pipeline
• Reduce PR Cycle Time — Speed up the code review bottleneck
• Cycle Time Breakdown — Understanding where time goes in development

Conclusion

The SDLC is a framework for understanding how software gets built—not a set of rules to follow rigidly. The best teams:

• Understand their actual flow—not the idealized version
• Measure each phase—especially wait time between phases
• Attack bottlenecks systematically—one at a time
• Automate repetitive work—especially testing and deployment
• Iterate continuously—the SDLC itself should evolve

Start by mapping your current flow. Where does work wait? That's your first improvement target. Use tools like CodePulse to measure the phases you can see in Git data—coding, review, and deployment. Then work backward from there to planning and forward to maintenance.