Agile guide
Agile explained: Scrum, Kanban, and Waterfall for career changers
Almost every tech job listing mentions Agile. Here is what it actually means, how it compares to the old way of building software, and what it looks like for each non-technical role.
The core idea
Waterfall builds software like a house — design everything first, then build, then test. The blueprint is fixed before a single brick is laid. This works for construction because the cost of changing a foundation after it is poured is enormous.
The problem: software requirements change constantly. Users ask for different things. The market shifts. The team learns something new. Agile fixes this by building in short cycles called sprints and adjusting constantly based on real feedback — instead of discovering problems only at the end.
Waterfall vs Agile
The difference is not just about speed — it is about when you learn whether you built the right thing.
WaterfallAgile
PlanningPlan everything upfrontPlan iteratively
ChangesHard to change mid-projectExpected and welcomed
DeliveryBig release at the endSmall releases every 1–4 weeks
Best forConstruction, hardware, complianceSoftware, SaaS, digital products
Scrum — the most common Agile framework
When someone says their team is Agile, they almost always mean Scrum. It structures work into sprints with five recurring ceremonies.
Sprints
2-week cyclesA sprint is a fixed, time-boxed period — usually two weeks — during which the team builds a specific set of features. At the start of each sprint the team commits to a plan; at the end they ship something real.
Sprint Planning
What gets built nextThe team reviews the top of the backlog, estimates the work, and decides what can be completed in the sprint. The Product Owner sets the priority; the dev team sets the capacity. The output is a sprint backlog — the committed list of stories.
Daily Standup
15 min sync, three questionsEvery working day, the team meets for a brief check-in. Each person answers three questions: What did I do yesterday? What will I do today? Are there any blockers? The standup is for coordination, not status reporting to a manager.
Sprint Review
Demo to stakeholdersAt the end of the sprint, the team demonstrates what was built to stakeholders and collects feedback. Work that does not meet the Definition of Done is not demoed — it goes back to the backlog.
Sprint Retrospective
What do we improve?After the review, the team reflects on the process itself: What went well? What did not? What is one thing we will do differently next sprint? Retros are where teams get better sprint over sprint.
The three Scrum roles
Product Owner
Sets prioritiesThe Product Owner owns the backlog — the ordered list of everything the product needs. They decide what to build next based on business value and user feedback. They write user stories and define acceptance criteria.
Scrum Master
Removes blockersThe Scrum Master is a servant-leader who keeps the team healthy and the process running. They facilitate ceremonies, shield the team from interruptions, and clear any impediment that is stopping work from moving forward.
Dev Team
Builds the productThe development team includes engineers, designers, and QA. They are cross-functional and self-organizing — they decide how to do the work, not just what to do. In Agile, QA is embedded on the team, not a separate gate.
Kanban — the continuous flow alternative
Kanban has no sprints. Work flows continuously from To Do to In Progress to Done — there is no time-box, no planning ceremony, no velocity. New work enters the queue as old work exits.
The key constraint is WIP limits — a maximum number of items allowed in each column at once. WIP limits prevent bottlenecks: if a column is full, no new work can enter until something moves forward. This forces the team to finish rather than start.
Best for: support teams, ops work, maintenance queues, and any workflow where work arrives unpredictably rather than being planned in advance.
Key Agile vocabulary you will hear in interviews
These five terms come up in almost every interview for a PM, BA, QA, or Scrum Master role.
Backlog
The prioritized list of all work to be done, owned and ordered by the Product Owner. The top of the backlog is what the team builds next.
Epic
A large piece of work that spans multiple sprints — for example, 'User Authentication' containing stories for registration, login, and password reset.
Story Points
Relative effort estimates using Fibonacci numbers (1, 2, 3, 5, 8, 13). A 3-point story is roughly three times the effort of a 1-point story. Points measure complexity, not hours.
Velocity
The number of story points a team completes per sprint, averaged over time. Used to forecast how much work can be planned for a future sprint.
Definition of Done
The shared agreement on what 'done' means for the team. Usually includes: code reviewed, tests passing, QA signed off, deployed to staging. A story is not done until every item is checked.
What each role does in Agile
Agile is a team sport. Each role has specific responsibilities within the sprint cycle.
PM / Product Owner
- Writes user stories and acceptance criteria
- Prioritizes and orders the backlog
- Makes trade-off decisions during sprint planning
- Participates in sprint review to accept or reject work
Business Analyst
- Refines requirements before they enter the sprint
- Clarifies acceptance criteria with the team
- Bridges the gap between stakeholders and dev team
- Documents edge cases and business rules on tickets
QA Engineer
- Tests each story during the sprint (shift-left testing)
- Writes test cases from acceptance criteria
- Files and tracks bugs in the same sprint they are found
- Signs off before a story is marked Done
Scrum Master
- Facilitates all five sprint ceremonies
- Removes blockers surfaced during standups
- Coaches the team on Agile practices
- Tracks velocity and flags process problems early
Apply this to your career
Learn your role in an Agile team
Understanding Agile theory is the start. See exactly what PMs, BAs, QAs, and Scrum Masters do day-to-day inside a real sprint.
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