What is the SDLC? The software development lifecycle explained
The software development lifecycle (SDLC) explained: its phases, the main models from waterfall to DevOps, and the controls each phase should have.
2 min read
Definition
The software development lifecycle (SDLC) is the sequence of stages a piece of software goes through, from the first idea to its retirement. It gives teams a shared structure to plan, build, test and release software with predictable quality.
The phases of the SDLC
- Planning: why the change is needed and what it is worth.
- Requirements: what exactly must be built.
- Design: how it will work and fit with the rest.
- Development: writing and reviewing the code.
- Testing: proving it does what was asked.
- Deployment: installing it in production under control.
- Maintenance: operating, supporting and improving it.
SDLC models
| Model | How it works | Fits when |
|---|---|---|
| Waterfall | Each phase finishes before the next one starts | Requirements are stable and well known |
| V-model | Each development phase has a matching test phase | Verification must be formal |
| Iterative | The product is built in successive versions | Learning is needed along the way |
| Agile | Short iterations deliver working software | Needs change often |
| DevOps | Agile plus continuous delivery and operation | Changes must reach production often and safely |
Controls in each phase
Whatever the model, auditors and security frameworks expect some controls: approved requirements, reviewed code, documented tests, authorized releases and a record of each change. The trick is to build them into the flow so they never depend on memory.
How DevGob helps
DevGob records each phase of the lifecycle on the change itself, from the business case to the production installation.
Read it in the documentationFrequently asked questions
What are the seven phases of the SDLC?
Planning, requirements, design, development, testing, deployment and maintenance. Some models merge or split them.
Is Agile an SDLC?
Agile is a family of SDLC models based on short iterations that deliver working software.
What is a secure SDLC?
An SDLC with security activities in every phase, such as threat modeling, code review and security testing.
Keep reading
DevOps with governance, on one record
DevGob plans the work and governs every change on its way to production: backlog, sprints, committee authorizations, install evidence and an audit trail.