Most Active Speaker

Jacob Duijzer

Jacob Duijzer

Helping developers, teams & organizations build better software | Engineering Manager | Team Topologies Advocate | Sooner Safer Happier Advocate

Vught, The Netherlands

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Jacob is a leader who inspires others through his commitment to learning, sharing knowledge, and fostering growth. With a strong foundation as a software developer, team lead, and technical consultant, he brings real-world experience to every role he takes on.
Jacob actively guides organizations through changes, such as adopting Team Topologies, and supports teams by mentoring developers, creating development teams, and leading workshops. His hands-on approach ensures that his ideas are practical and grounded in experience.
Driven by a passion for helping people and teams succeed, Jacob focuses on building strong, collaborative environments. He combines technical expertise with leadership to advocate for better ways of working and continuous improvement.

Badges

  • Most Active Speaker 2024

Area of Expertise

  • Business & Management
  • Information & Communications Technology

Topics

  • Polly
  • Chaos Engineering
  • Specification By Example
  • Coding Cojo
  • Code Retreat
  • .NET
  • Linux
  • Team Topologies
  • DevOps
  • Domain Driven Design
  • Leadership
  • Agile Coaching
  • Agile Leadership
  • TDD & BDD
  • BDD
  • DDD
  • IT Leadership
  • Technical Leadership
  • Team Leading
  • Agile Coach
  • liberating structures
  • engineering management
  • Software Engineering Management
  • Engineering Culture & Leadership
  • Platform Engineering
  • Software Engineering
  • engineering leadership
  • Engineering Culture

Sessions

Chaos Engineering: unleash the monkeysennl

Large online organisations like Netflix, Amazon and LinkedIn are already doing it for years: Chaos Engineering, injecting chaos in their production environments. And while it might sound scary (and it will be in the beginning), even you can apply some chaos in your applications. In this talk I will demonstrate how to create chaos and how to apply resilience to work around this chaos and create a more stable platform.

In this session we will look at the Chaos Monkey Pizza shop, an event-driven, microservice oriented web application where you can order pizzas. The application will be running on Kubernetes, have a frontend, a GraphQL API, RabbitMQ and a few .NET microservices. When everything is running smoothly we will apply chaos on different compontents and try to solve this chaos with different scenario's.

While trying to manage the application it will become apparent that it is not only logging that is important but also traceability and metrics.

The Road to Faster Flow Is Paved with Missteps: A Retrospectiveen

Two years ago, we set out on a journey to transition to a Team Topologies-inspired organization, aiming to unlock faster flow and better collaboration. Today, it's time to reflect on the lessons learned along the way.

Looking back, what I see is not a straight road, paved with tarmac. No, it is a twisting road, with potholes and puddles, with some broken down and rusted vehicles here and there.

We often hear polished success stories, but we can also learn a lot about the bumps and wrong turns. These stories don't need to be dark or cynical, there are many small successes and golden nuggets of insights to be found.

So let's have a retrospective, and try and find some answers on what went wrong, and what worked well. Let's try and identify patterns and anti-patterns to learn from our mistakes and build on our wins.

Key takeaways:

- Embrace the Mess
- Celebrate Small Wins
- Beware of Anti-Patterns

Take a ride with me on this bumpy road, and learn from our lessons, for a smoother road ahead.

GraphQL is cooler than (the) REST!ennl

If you're tired of over-fetching, under-fetching, or feeling constrained by rigid endpoints, this is your chance to learn more about a cool alternative for REST.In this session we'll cover the essentials—from understanding its structure and benefits to the strategic considerations that will help you decide whether to make the switch. There will be a lot of code and demo’s, we’ll try to cover as much possibilities of GraphQL as possible in the given time.

Here’s what you will take away::
The biggest difference between REST and GraphQL
The strengths of GraphQL and how they can empower your development
The potential weaknesses to watch out for
What you need to get started

Let's dive into why GraphQL is cooler than REST!

Fast Flow, Not Fast Fluff: Embracing an Eclectic DevOps Coaching Approachen

Sometimes it feels like sailing against the wind: delivering value for our customers. There are so many obstacles that it might feel like navigating through a labyrinth of uncertainties. Sometimes we might know how to fix “our part”, but fixing the whole is a completely different challenge.

In this session, we will talk about an eclectic approach to change, by leveraging Team Topologies, DevOps, Lean, and Agile principles. We will talk about how a Team-First approach, with a strong focus on the outcome, can help to achieve great results. But we might also discover that having fun at work actually helps in delivering more value, sooner, safer, and happier!

Living in your own bubbleen

There are a lot of farms in the Netherlands, and a lot of cows. All cows on a farm have a certain value, based on their history. Cows are sold and bought, being born and slaughtered, inseminated or milked, generating a large stream of information. Information which is used by the farmers but also by the government. Taxes, carbon footprints, CO2 reductions, business value, it all needs up-to-date and accurate animal information.

Due to new laws, some serious changes had to be implemented on a legacy system. Nightly processing of new information was already problematic, extending the business rules would even make it slower. Scaling and extending the legacy application, which heavily leaned on stored procedures and triggers, appeared to be too difficult. While Domain Driven Design could really help to bring clarity in this complex domain, rebuilding was not an option.

Time to introduce the Bubble Context of which Eric Evans wrote in his paper “Getting Started With DDD When Surrounded By Legacy systems”! In this session I will use a simplified version of the legacy system and demonstrate how to create your own bubble context to apply new business rules while keeping the existing system intact. In fact, we hardly touch the existing system! I will explain the advantages and disadvantages of a bubble context and how to move even further away from the legacy system.

Empowering Teams for High-Performance: Unleashing the Potential of Team Topologies and DevOpsen

In today's fast-paced and dynamic business environment, organizations strive to build and scale high-performing technology teams that can deliver value with speed and efficiency. To achieve this, a combination of effective team organization and continuous improvement practices is essential. In this talk, we will explore how the concepts of Team Topologies and DevOps can be leveraged from the perspective of an enabling team, such as an agile coach, to empower organizations and teams.

Software leveren met de snelheid van het lichtnl

Stel je jezelf ook wel eens de volgende vragen?

Wat is het grote verschil tussen de beste- en slechts presterende softwareteams?

Zijn er overeenkomsten bij de best presterende organisaties als het gaat om het ontwikkelen van software?

Wat kunnen wij daarvan leren en misschien zelfs toepassen in ons team of onze organisatie?

Het State of DevOps researchproject, uitgevoerd door DevOps Research & Assessment (DORA), doet hier al jaren onderzoek naar. Zowel de uitkomsten als de vragen van dit onderzoek kunnen helpen om jouw team of organisatie te verbeteren! Uit de resultaten van eerdere onderzoeken zijn 24 punten gekomen die, statistisch gezien, zorgen voor de belangrijkste verbeteringen in het proces van softwareontwikkeling.

De belangrijkste uitkomsten uit het onderzoek wil ik, samen met jullie, wil bespreken. Wat is de achterliggende gedachte achter de verschillende punten? Wat heeft het DORA researchproject te zeggen over mogelijke veranderingen en implementaties? Welke obstakels zou je tegen kunnen komen? De onderwerpen zijn niet alleen technisch van aard, maar gaan ook over processen en cultuur, veranderingen die in eerste instantie eenvoudig lijken kunnen tot de kern van jouw organisatie doordringen.

Na afloop van deze sessie heb je inzicht in de resultaten van jaren onderzoek naar de staat van DevOps. Je weet wat de belangrijkste aandachtspunten zijn om succesvol te kunnen versnellen in het leveren van software. Met behulp van de opgedane kennis kun je onderzoek doen naar de staat van jouw team en organisatie, verbeterpunten identificeren en daadwerkelijk bijdragen aan veranderingen die noodzakelijk zijn om software sneller te kunnen leveren.

Specification by Example: building the right things the right waynlen

Specification by Example: een term die zich niet goed in het Nederlands laat vertalen maar waar ‘samenwerking in de praktijk’ centraal staat. De meest ideale infrastructuur neerleggen om goede communicatie mogelijk te maken. En dat is iets waar het in de softwarewereld nog wel eens aan ontbreekt. Dat vraagt om de juiste manier van samenwerken tussen de betrokken partijen zodat elementen die als frustrerend, blokkerend of remmend kunnen worden ervaren, worden weggenomen. Samen ga je zo nauwkeurig mogelijk omschrijven waar de software in resulteert.

Je kent allemaal de frustratie wel: als stakeholder of als developer, als analist of als tester. We hebben elkaar niet goed begrepen en het verkeerde gerealiseerd. Details zijn verloren gegaan. Gesprekken zijn niet goed uitgewerkt. Concepten zijn verkeerd begrepen. Ook al werken we volgens agile-methodieken en kunnen we tijdig ingrijpen en bijsturen, het is nog steeds kostbaar. Het kan ten koste gaan van vertrouwen in elkaar en in de kwaliteit. Specification by Example is een goed middel om de kwaliteit van de samenwerking en daarmee de kwaliteit van de software te verbeteren.

Deze presentatie is niet alleen theoretisch van aard. Het doel is om - met behulp van praktijkvoorbeelden - te laten zien hoe je een begin kunt maken met Specification by Example: niet alleen voor het beschrijven van specificaties maar ook hoe je deze specificaties kunt automatiseren.

Een aantal onderwerpen dat aan bod komt:

- Samenwerking

- Belangrijke processen

- Hoe beschrijf je specificaties

- Gezamenlijke taalontwikkeling (ubiquitous language)

- Levende documentatie

- Het automatiseren van specificaties

- Valkuilen & mislukkingen en succesverhalen

Na afloop van deze presentatie weet je hoe je Specification by Example kunt inzetten voor het verbeteren van het ontwikkelproces. Je kent een aantal valkuilen en je weet hoe je op kleine schaal een aanzet kunt maken. Daarnaast heb je voldoende kennis om het gesprek aan te gaan over Specification by Example: met je team, je opdrachtgever of werkgever.

DevOpsDays Amsterdam

June 2025 Amsterdam, The Netherlands

Fast Flow Conf NL 2025Sessionize Event

March 2025 's-Hertogenbosch, The Netherlands

devConf 2025Sessionize Event

March 2025 Heerlen, The Netherlands

2024 All Day DevOps Sessionize Event

October 2024

Domain-Driven Design Europe 2024Sessionize Event

May 2024 Amsterdam, The Netherlands

Living Documentation Event (LDE24)

April 2024 Eindhoven, The Netherlands

Future Tech 2024Sessionize Event

April 2024 Utrecht, The Netherlands

WeAreDevelopers Live 2024 (Season 7)Sessionize Event

January 2024

DeveloperWeek Enterprise 2023Sessionize Event

November 2023

Tweakers Developers Summit

September 2023 Utrecht, The Netherlands

Domain-Driven Design Europe 2023Sessionize Event

June 2023 Amsterdam, The Netherlands

JetBrains .NET Days Online 2022Sessionize Event

October 2022

Jacob Duijzer

Helping developers, teams & organizations build better software | Engineering Manager | Team Topologies Advocate | Sooner Safer Happier Advocate

Vught, The Netherlands

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