SDLC for WordPress Developers: The Cycle Behind Every Project
Born in the 1960s. Still relevant in the AI era.
You already use SDLC. Every task goes through it: someone wants something, you clarify it, decide how to build it, write the code, check it, ship it and fix it later. Many WordPress developers know the process by heart and have never used the letters. Developers say “task”, “flow”, “release”. Managers, tech leads and hiring teams say SDLC.
This page translates that manager’s word into a developer’s language.
What SDLC Is
SDLC stands for Software Development Life Cycle: the phases software goes through from an idea to the day it is switched off. On this page there are seven:
- Plan: why we build it, what it is worth, what the risks are.
- Requirements: what exactly it must do.
- Design: how it will be built.
- Build: the code.
- Test: proof that it works.
- Deploy: getting it live.
- Maintain: keeping it alive, then feeding the next Plan.
Sources split the cycle into five to eight phases and name them differently. The order stays the same.
SDLC Is the Umbrella, Not a Methodology
Waterfall, Agile, Scrum and Kanban are ways of walking through the same phases. SDLC is what they all walk through. All of them are listed under Methodologies.
The phases are the ribs of the umbrella. Remove one and the canopy fails:
- Skip Requirements and you build the wrong thing well.
- Skip Design and every new feature fights the old ones.
- Skip Test and your users test for you.
- Skip Maintain and the site slowly rots under plugin, core and PHP updates.
Sixty Years of Weather
- 1968: the software crisis. At the NATO Software Engineering Conference in Garmisch, Germany, participants discussed what became known as the “software crisis”: projects late, over budget and unreliable. The answer was engineering discipline, and with it a defined cycle.
- 1970: Waterfall. Winston W. Royce published “Managing the Development of Large Software Systems”. Its sequential diagram later got the name Waterfall, although Royce himself warned that running it strictly one way was risky.
- 2001: Agile. The Agile Manifesto did not remove the phases. It made the cycle short and repeated it. A sprint is a small SDLC.
- 2009: DevOps. The term spread after the first DevOpsDays in Ghent. Deploy and Maintain became continuous: see CI/CD for WordPress and GitHub Actions.
- 2020s: AI. Coding tools made Build cheap. The other six phases did not get cheaper.
The weather changes. The cycle stays.
Three People Under One Umbrella
The same phase looks different depending on who holds the umbrella.
| Phase | Client asks | Project asks | Developer asks |
|---|---|---|---|
| Plan | Why are we doing this, and what is it worth? | Scope, budget, deadline, risks. | Is it feasible on WordPress? Existing plugin, custom plugin or theme code? |
| Requirements | What must the site do for my users? | Turn wishes into a list that can be accepted or rejected. | Roles and capabilities, content types, edge cases, integrations. |
| Design | How will it look and feel? | Is the solution the right size for the budget? | Data model, hooks, blocks or templates, REST routes, where each piece of code lives. |
| Build | When can I see it? | Progress against the plan. | Plugin and theme code, migrations, configuration. |
| Test | Does it work on my phone? | Is it ready to ship? | Unit and end-to-end tests, coding standards, capabilities, nonces, escaping. |
| Deploy | Is it live? | Release window and rollback plan. | Staging to production, WP-CLI, database, cache. |
| Maintain | Will it keep working? | Support cost and update schedule. | Core, plugin and PHP updates, security fixes, monitoring. |
On a small WordPress project one person often wears all three hats. A freelancer is the project manager and the developer, and often helps the client decide what they want. That is where SDLC stops being a manager’s word.
SDLC on a WordPress Project
Each phase already has a home on 4wp.dev:
- Plan: Lean (MVP), Design Thinking.
- Requirements: BDD, Ubiquitous Language.
- Design: Architectures, SOLID, Essential Principles, Domain-Driven Design, database schema, API-first, Block-first.
- Build: Hooks, Gutenberg Blocks, REST API, WordPress Coding Standards, Git, Composer.
- Test: TDD, Security.
- Deploy: CI/CD for WordPress, WP-CLI, Twelve-Factor App, GitHub Flow.
- Maintain: Site Reliability Engineering, WP-CLI profiling, performance.
From Developer to Tech Lead
Build is one rib out of seven. A developer who only builds competes with every tool that builds.
A developer who holds all seven asks why before writing code, pins down what “done” means, decides where the code lives, proves it works, ships it safely and keeps it alive. That developer is already doing a tech lead’s job, whatever the title says. With the right personal qualities, that is the natural next step.
The AI era asks for exactly this: not a developer who types fast, but a fullstack developer who thinks like an architect. If you cannot connect the phases, every one of them becomes harder. More on the cost of that in The Price of Attention.
AI Took One Rib
AI coding tools write code fast. They do not decide what to build, they do not own the trade-offs, and they do not own the rollback.
- Vague requirements give you vague code, only faster.
- More generated code means more code to review and test.
- Architecture decides whether generated code fits the system or fights it.
AI took Build. Six ribs are still yours. See AI Workflows for WordPress for how we split the work with agents.
FAQ
Software Development Life Cycle: the phases software goes through from an idea to retirement.
No. Waterfall is one way to walk through the cycle: one phase after another, once. Agile, Scrum and Kanban walk through the same phases in short, repeated loops.
Yes. Agile made the cycle shorter, DevOps made Deploy and Maintain continuous, and AI made Build cheaper. None of them removed a phase.
Yes, more than anyone. A solo developer is the planner, the architect, the tester and the support team. Knowing the phases helps you see which one you skipped.