Blog
Mert Özen's blog posts on software development, backend, frontend, and DevOps.
The Product Backlog and the Product Goal: What We Build and Why
The Product Backlog is the ordered, emergent list that is the single source of the Scrum Team's work; its commitment, the Product Goal, says why the list exists. The post shows how ordering weighs value, risk, dependencies and the cost of waiting, why refinement is not an event, and when a Definition of Ready, which is not in the Guide, becomes a gatekeeper, using Bookstore's GitHub Projects backlog.
The Scrum Team and Its Accountabilities: Product Owner, Scrum Master and Developers
In the Scrum Guide 2020 there is a single Scrum Team with three accountabilities: a one-person Product Owner who maximizes value, a Scrum Master accountable for the team's effectiveness, and Developers, testers, DevOps and designers included, who create the Increment. The post covers the shift from roles to accountabilities and from Development Team to Developers, and the traps of a Product Owner committee, proxies, separate QA teams and secretary Scrum Masters, using the Bookstore team.
What Is Scrum? Empiricism, Lean Thinking and the Problem Scrum Solves
Scrum is a purposefully incomplete, lightweight framework for generating value in complex problems: three accountabilities, five events, three artifacts and one commitment per artifact. The post explains the three pillars of empiricism, lean thinking and the five values through the Bookstore team's first Sprint preparation, and shows that velocity, story points, user stories and the three Daily Scrum questions are not in the Guide.
The Evolution of Agile: From the Manifesto to Modern Agile and the Scaling Debate
Since 2001 Agile has both become institutionalized and tried to return to its essence through proposals such as Heart of Agile and Modern Agile; the Agile Fluency Model offers consciously chosen zones, not a maturity ladder. We summarize SAFe, LeSS, Nexus and the Spotify model (which isn't really a framework) with their critiques, show through Bookstore's six teams why buying a framework isn't becoming Agile, and give a short self-check list.
Agile Meets Reality: Fixed-Price Contracts, Deadlines and Architecture
Agile turns the project triangle upside down: time and team are fixed, scope is the variable, and a fixed price doesn't have to mean fixed scope. Using Bookstore's B2B portal and campaign deadline, we cover Sutherland's change for free and money for nothing clauses, MoSCoW slicing that keeps Must have effort under 60 percent, and the architecture runway with early decisions on what is expensive to reverse (database, auth, multi-tenancy).
Agile Myths: No Documentation, No Planning and "Agile Means Scrum"
Agile has documentation, planning and architecture; it promises early feedback rather than speed, and it isn't the same as Scrum or Jira. We compare seven common myths with the text of the manifesto, summarize Fowler's Agile Industrial Complex critique, Dave Thomas's "agility" proposal and Dark Scrum, and list the symptoms of cargo cult Agile through the "transformation" of the company Bookstore belongs to.
Extreme Programming (XP): The Engineering Side of Agile
Extreme Programming (XP) is the side of Agile that lives inside the code: test-first, pair programming, continuous integration, small releases, refactoring and collective code ownership form a system that supports itself. Scrum doesn't define these practices, and Fowler's Flaccid Scrum warning describes exactly that gap; with real output we show a pair writing Bookstore's free shipping rule test-first and getting it onto trunk in small commits within minutes.
The 12 Agile Principles Through a Developer's Eyes
The 12 Agile principles fall into six themes: delivery and feedback, openness to change, collaboration, sustainable pace, technical excellence and simplicity, and self-organizing teams with reflection. We connect each principle to concrete practices such as small PRs, feature flags, CI and YAGNI, show how the principles break in a chain during two weeks of the Bookstore team, and why the unmeasured sustainable pace principle is the sneakiest trap.
The Agile Manifesto: What Happened at Snowbird in 2001 and What the Four Values Really Say
The four values of the Agile Manifesto are a list of priorities, not prohibitions: the manifesto explicitly says there is value in the items on the right (process, documentation, contracts, plans) too. Using the Bookstore team, we explain what the 17 people who met at Snowbird in February 2001 were reacting to, what each value means for a developer, and why documents such as OpenAPI specs, ADRs and READMEs are still needed.
Choosing the Right SDLC Model for Your Project, Team and Risk Profile
The right SDLC model is chosen by the project's risk profile, not the team's habits: requirements uncertainty, regulation, contract type, deployment cost and access to feedback. We use Cynefin to separate complicated from complex problems, build a decision table, and honestly describe conscious hybrid models for Bookstore's bank integration, subscription product and internal reporting work.
From Waterfall to Agile and DevOps: Why the Feedback Loop Shrank from Months to Hours
The feedback loop shrank as the fixed cost of deployment fell: cheaper deployments meant smaller batches, and smaller batches reduced both risk and the time to find a bug. We trace the line from the lightweight methods of the 1990s to the Agile Manifesto, DevOps in 2009 and Continuous Delivery, and cover DORA's five metrics, shift-left and the water-scrum-fall trap of running sprints while still releasing once a quarter.
Incremental, Iterative and Spiral Models: Surfacing Risk Early
Incremental development adds the system part by part, iterative development builds the whole roughly and reworks it; Cockburn recommends using both together. We start Bookstore's checkout with a walking skeleton and grow it in slices, and cover Boehm's risk-driven Spiral model, throwaway vs evolutionary prototypes, RAD and RUP's four phases, together with the pitfall of mini-Waterfall disguised as iterations.