Agile
"Iterative, incremental delivery; respond to change; people and collaboration over process"
What is Agile?
Agile is a mindset and set of practices for building software in small, frequent increments. Teams deliver value early, get feedback, and adapt plans instead of following a rigid, upfront plan.
Memory hook
"Iterate → deliver → learn → adapt; not big-bang, not fixed scope"
Agile Manifesto (four values)
- Individuals and interactions over processes and tools
- Working software over comprehensive documentation
- Customer collaboration over contract negotiation
- Responding to change over following a plan
(The right-hand items still matter; the left-hand items are valued more.)
Twelve principles (highlights)
- Satisfy the customer through early, continuous delivery
- Welcome changing requirements; harness change for advantage
- Deliver working software frequently (weeks, not months)
- Business and developers work together daily
- Build projects around motivated individuals; trust them
- Prefer face-to-face conversation
- Working software is the primary measure of progress
- Sustainable pace (no burnout)
- Technical excellence and good design enhance agility
- Simplicity—maximize work not done
- Self-organizing teams
- Reflect and tune behavior at regular intervals
Scrum vs Kanban (common frameworks)
| Aspect | Scrum | Kanban |
|---|---|---|
| Cadence | Fixed-length sprints (e.g. 2 weeks) | Continuous flow |
| Roles | Scrum Master, Product Owner, Dev Team | No prescribed roles |
| Commitment | Sprint goal / sprint backlog | WIP limits per column |
| Change | Scope fixed within sprint | Can add/reprioritize anytime |
| Metrics | Velocity, burndown | Lead time, cycle time, throughput |
- Scrum — time-boxed sprints, defined roles, sprint planning and review
- Kanban — visualize work (board), limit WIP, manage flow; no sprints
Scrum in short
Roles
- Product Owner — owns backlog, prioritizes, clarifies “what”
- Scrum Master — facilitates process, removes blockers, protects team
- Development Team — designs, builds, tests; cross-functional and self-organizing
Ceremonies
- Sprint Planning — what to do this sprint; pick from backlog
- Daily Scrum (Stand-up) — short sync: what I did, what I’ll do, blockers
- Sprint Review (Demo) — show done work to stakeholders
- Sprint Retrospective — what went well, what to improve
- Backlog Refinement — clarify and estimate items for future sprints
Artifacts
- Product Backlog — ordered list of all work (features, bugs, tech debt)
- Sprint Backlog — subset of backlog committed for current sprint
- Increment — done, shippable work at end of sprint
Key concepts
- Sprint — fixed time box (often 2 weeks)
- Definition of Done — shared criteria for “done” (code review, tests, deployable, etc.)
- Velocity — (optional) amount of work completed per sprint, used for forecasting
Kanban in short
- Board — columns (e.g. To Do, In Progress, Done)
- WIP limits — max items per column to avoid overload and improve flow
- Pull — work is pulled when capacity allows, not pushed
- Continuous flow — no sprints; work moves through stages
- Metrics — lead time (request → done), cycle time (start → done), throughput (items per period)
Common terms
- User story — short description of value for a user (e.g. “As a …, I want … so that …”)
- Epic — large body of work; broken into stories
- Backlog — list of work to do (prioritized in Scrum)
- Sprint — time box in Scrum (e.g. 2 weeks)
- Stand-up — short daily sync (what I did, what I’ll do, blockers)
- Retro — reflection on process and team behavior
- Velocity — (Scrum) work completed per sprint; used for planning
- WIP — work in progress; in Kanban, WIP limits control flow
Interview one-liner
"Agile is iterative delivery and responding to change. Scrum uses sprints, roles (PO, SM, team), and ceremonies (planning, stand-up, review, retro). Kanban uses a board, WIP limits, and continuous flow. Both focus on working software, feedback, and adapting."
Cheat sheet
Agile = iterate, deliver, learn, adapt
Manifesto: people, working software, collaboration, change
Scrum = sprints + PO + SM + team + ceremonies + backlog
Kanban = board + WIP limits + flow, no sprints
Ceremonies: planning, stand-up, review, retro
Artifacts: product backlog, sprint backlog, increment