Sertaç Yıldırım field notes

Writing about how the things that look good in the book actually work in the field.

Notes on Scrum ceremonies, team leadership and software engineering. Every post follows the same skeleton: what it is for → how it should work → how it breaks → checklist. Practice, not theory.

39 posts · 3 sections · available in Turkish and English

01 — 9 posts

Scrum and Process

The ceremonies are a chain: broken refinement makes planning drag, broken planning turns the daily into a status report. That is why these are written to be read in order.

PART 01

Being Agile vs Doing Scrum

Agile does not end the chaos; it makes it visible. That is why teams can run every ceremony and still not be agile.

21 September 2025 · agile · manifesto · scrum
PART 02

Backlog Refinement: Kill Bad Ideas Early

Refinement is a funnel, not a meeting. Back-of-the-envelope filtering and ROI in one shared currency.

1 October 2025 · refinement · roi · prioritization
PART 03

Grooming: Not a Ticket Reading Session

The PO's job is not to read out what will be built, but to explain why it matters.

12 October 2025 · grooming · product owner · context
PART 04

Sprint Planning: Commitment, Not Estimation

Good planning is boring. If surprises show up, the preparation failed. Capacity math and the pull system.

26 October 2025 · planning · capacity · pull system
PART 05

Daily Standup: Synchronization, Not a Status Report

If what you did yesterday does not affect today, it does not matter. Walking the board, and the async option.

8 November 2025 · daily · standup · async
PART 06

Sprint Review: A Feedback Loop, Not a Demo Show

If nobody objects, nobody is listening. Silence is the worst signal.

23 November 2025 · review · stakeholders · feedback
PART 07

Retrospective: Tracked Actions, Not Wishes

Definition, owner, deadline — without all three it is a wish, not an action.

6 December 2025 · retro · kaizen · psychological safety
PART 08

Epic, Story, Task: How to Break Work Down

Why should a task never exceed one day? Six ways to cut work, walked through a real e-commerce returns project.

20 December 2025 · user story · task breakdown · 8 hours
PART 09

Does Scrum Make Customers Happy?

Bringing the customer inside: from 1 project to 9, from 1 person to a team of 14. A real story from the field.

4 January 2026 · customer · ownership · growth
02 — 13 posts

Team Leadership

The human side rather than the process: hard conversations, performance, what replaced authority, and what a manager is actually for in the age of AI.

LEADERSHIP

How to Give Negative Feedback

Why does the sandwich fail? The event → impact → expectation pattern, with real dialogue.

17 January 2026 · feedback · hard conversations
LEADERSHIP

Can You Measure Performance With OKRs?

Tie a bonus to a target and people shrink the target. Why story points inflate, and what to read instead.

1 February 2026 · okr · performance · kpi
LEADERSHIP

New-Generation Leadership: Authority Is Gone, Now What?

The information monopoly ended, dependence ended. What replaced them, and the power of "I do not know".

14 February 2026 · leadership · authority · context
LEADERSHIP

AI or Leadership?

Writing got cheap, verifying got expensive. The junior learning path and the leader's changed job.

1 March 2026 · ai · leadership · juniors
LEADERSHIP

Squad, Tribe, Chapter, Guild: Choosing an Org Model in One Week

The first target handed to me in a meeting with the CEO. 52 conversations, a one-sentence diagnosis, and what we left out of the Spotify model.

7 March 2026 · spotify model · squad · org design
LEADERSHIP

One-on-Ones: An Early Warning System, Not a Status Meeting

Thirty minutes a week, and the agenda is theirs. Why "how is it going?" always returns "fine", and what to ask instead.

15 March 2026 · 1:1 · management · listening
LEADERSHIP

Developer to Manager: A Career Change, Not a Promotion

Promoting your best engineer can lose you twice. The right measure for how much code to keep writing.

29 March 2026 · management · transition · technical leadership
LEADERSHIP

Delegation: Letting Go of the Outcome, Not Handing Out Tasks

Hand work over and then hover, and you have not delegated. Authority with responsibility, and the ten-minute trap.

12 April 2026 · delegation · micromanagement · trust
LEADERSHIP

Psychological Safety: Measurable Behaviour, Not Good Intentions

Saying "speak freely" does not do it. Who speaks first, how late bad news arrives, and how incident reviews kill it.

26 April 2026 · psychological safety · blameless · culture
LEADERSHIP

Conflict: Surface It, Don't Suppress It

Two seniors disagree on architecture and the team picks sides. Separating ideas from people, and deciding who decides.

10 May 2026 · conflict · decisions · architecture
LEADERSHIP

Burnout and Load: Sustainable Pace, Not Heroes

The person who saves every sprint is a single point of failure. On-call load and the signs of quiet overwork.

24 May 2026 · burnout · on-call · sustainability
LEADERSHIP

Growing a Team: Five People and Fifteen Are Not the Same Job

Past seven, communication paths multiply. When to split, Conway's law, and what "two pizzas" really says.

7 June 2026 · scaling · conway · team topology
LEADERSHIP

Managing Up: Setting Expectations, Not Filing Reports

When do you say "the sprint will slip"? The arithmetic of early bad news, and shielding versus hiding.

21 June 2026 · stakeholders · expectations · transparency
03 — 17 posts

Engineering

Concurrency, distributed systems, messaging, scaling and coding with AI — all with real incidents and code examples.

ENGINEERING

Race Conditions: Why Does Stock Go Negative?

Invisible in staging, catastrophic on sale day. Six fixes, with SQL examples.

14 March 2026 · concurrency · database · sql
ENGINEERING

Distributed Locks: Getting It Right

Six traps in a Redis lock, fencing tokens, and the fact that most cases need no lock at all.

25 March 2026 · redis · distributed · fencing
ENGINEERING

Worker Sharding: The Right Way to Split Work

Four workers, one at 100% CPU and three idle. Hot keys, rebalancing and ordering guarantees.

26 April 2026 · sharding · queues · partitions
ENGINEERING

How Pod Scaling Actually Works

Pods went from 4 to 24 and the system got slower. Why is CPU the wrong metric?

9 May 2026 · kubernetes · hpa · scaling
ENGINEERING

Vibe Coding Rituals

Why does three hours of work turn into two days of debugging? Ten habits that work.

30 August 2026 · ai · code quality
ENGINEERING

Leader Election: Who Does This Job?

Four copies, all running the health check. Leases, split-brain and fencing tokens.

11 April 2026 · leader election · lease · fencing
ENGINEERING

How Many Times Does a Message Arrive?

At-least-once, at-most-once and the exactly-once myth. Idempotency keys and dedup, with code.

24 May 2026 · idempotency · kafka · dedup
ENGINEERING

Queue Pathologies

Poison messages, DLQs, jitter, head-of-line blocking, reordering and backpressure — all five.

6 June 2026 · dlq · backoff · backpressure
ENGINEERING

Failure Modes

Thundering herds, cache stampedes, cascades, circuit breakers, gray failure and failover loss.

18 June 2026 · circuit breaker · cascade · failover
ENGINEERING

Distributed Transactions: Why 2PC Blocks and Saga Saves You

One leg filled, the other rejected. Compensating transactions and the escrow pattern.

4 July 2026 · saga · 2pc · compensation
ENGINEERING

The Dual Write Problem: Outbox, Inbox and CDC

The order was written but the event never published. Why atomic dual writes are impossible.

19 July 2026 · outbox · cdc · debezium
ENGINEERING

CQRS and Materialized Views

The portfolio screen takes 8 seconds, the order path needs 3 ms. Separating reads from writes.

1 August 2026 · cqrs · read model · consistency
ENGINEERING

Where Did the 200 ms Go?

Six services add up to 40 ms while the customer waits 240 ms. Correlation IDs and traces.

16 August 2026 · tracing · correlation id · observability
ENGINEERING

Monolith to Microservices: What Five Months Taught Us

The distributed monolith, double shipments, a cancelled order at the door, and the two services we merged back — with numbers.

11 September 2026 · microservices · event driven · strangler
ENGINEERING

Logs and Metrics in Microservices: One Screen, Not Six Log Files

Prometheus, Loki and Grafana on one screen. The four golden signals, structured logs, a 2.4-million-series cardinality accident, and why the CPU alert was useless.

12 September 2026 · observability · prometheus · loki · grafana
ENGINEERING

Don’t Say “I Have an SMS Code, I’m Safe”: Step-Up Authentication with Passkeys for Withdrawals

The JWT was valid and $4,800 went to a new IBAN. A challenge bound to amount and IBAN, a free margin re-check, and the back door on the “add passkey” screen.

16 September 2026 · security · passkey · webauthn · jwt
ENGINEERING

SOLID: A Tool, Not a Goal — When to Use It, When to Skip It

Two interfaces, two classes and a factory for a one-line welcome message. The five principles with code; the signals where they help, the cases where they only add files; YAGNI and the rule of three.

16 September 2026 · solid · design · yagni · c#

Who this is for

In short

If sprints keep spilling over and nobody looks at the retro actions; if you keep postponing the hard conversations in your team; or if your system runs perfectly in staging and falls over on the morning of a campaign — you are in the right place.

The three sections are really the same team’s three different problems: process, people and systems. And they are usually connected — the answer to why a sprint spilled over is sometimes in a queue design, and sometimes in a sentence nobody said out loud.

Every post ends with a checklist; if you are in a hurry, read only those and share them with your team.