Excellence for Leaders who understand you must keep growing

Trainings | peer groups | events

Whatclients say about us

Jeroen Brouwers CPO @ Vesper

Being part of the Group Effort peer group is incredibly valuable. It provides a platform for exchanging ideas, best practices and learnings with people in the same position.

Gijs Hendrix CPTO @ Appical

As the most senior product person in my organisation, it's very hard to get useful feedback. This is what the Group Effort peer group provides me, as well as opportunities to get challenged and grow. It's been incredibly valuable.

Miranda Ippel Head of Product @ Twelve

In the peer group sessions, Martyn listens attentively, intervenes when the conversation veers off course, and frequently employs metaphors for clarification. He remembers the main themes from previous sessions for each individual, which deepens the conversations and advice. This is not only impressive but also extremely valuable for the participants.

Arco Westbroek CPO @ Carerix

It's very useful to share knowledge and be challenged by people in the same role within other companies. It's also fun to only need half a sentence to understand each other and have a relevant conversation.

Tom van der Woude Head of Product

The peergroups give me the opportunity to learn from the experiences of Heads of Products. I notice that more and more often I find myself in situations where I can apply what my peers have already experienced and learned and I can apply that knowledge to make judgment calls or prevent making mistakes that I would have probably made otherwise.

Jelle Kamsma Head of Product @ ANP

Martijn is an excellent facilitator who always has a metaphor or story at hand to help you reframe your thinking.

Sjoerd van den Biggelaar Product Owner @ Eurofiber

Every day, distractions come by that you can use as an excuse to neglect or postpone less enjoyable but more important matters. Martijn made me aware of the distractions of the day and the choices I was making unconsciously. He didn't do this by telling me what to do, but by skillfully coaching me in the right direction with questions and tools to help me understand the situation myself.

Peter Deumer Director of Software Development

As a coach, Martyn managed to provide a mirror instead of advice. Based on what I saw in that mirror I managed to identify certain aspects of myself, both personal and business, that I wanted to work on. I very much liked his approach towards sustainable improvement.

What do we do?

Depending on your needs, we offer different services:

Training/Coaching

Martijn worked over 200+ product & tech leaders across Europe.

This gave him a very specific expertise to help you grow your people.

If you need your product or tech department to level up, don’t hesitate to reach out. The best way to do this is to reach out to Martijn directly using LinkedIn.

Peer Groups

Imagine the insights you could gain from 7 experienced leaders in your field.

When you join a peer group for leaders like you, you can leverage the experience from all the others.

It’s like getting 10 peers directly in your pocket. Peers you meet multiple times a year.

(Un)Conferences

Small scale (un)conferences for senior leaders. The 2025 Product Mastery Conference had an amazing speaker (Marty Cagan) and got us an NPS of over 60!

The second, the Tech Mastery Unconference, had over 550 years of experience among attendees from 14 countries.

Right now, we’re arranging the Product Mastery Conference 2026 with Melissa Perri. More info at:

Free goodies

If you don't know me yet, you might want to get a taste before you commit. Just for that case, I make free content for your benefit:

What does it look like?

Coaching is always tailor made. The intake is always on location in either Hilversum or Berlin.

After forming a solid coaching question, it is determined how many sessions are needed to achieve this. We have a 100% success guarantee.

Over the course of a year you meet up with your group of experts under the guidance of an experienced coach.

Together you break bread, tackle challenging cases and discuss developments in your industry that affect you all.

Over the course of a year you meet up with your group of experts under the guidance of an experienced coach.

Together you break bread, tackle challenging cases and discuss developments in your industry that affect you all.

Current OPEN peer groups

CEOs

To keep the company growing, you have to keep growing yourself. One of the biggest dangers is that you might develop blind-spots on the way. These groups give you perspective.

COOs

Being a COO is a very special role. Your company grows, and as it does it requires you to grow with it. The different growth stages require different things from you. We match you with COOs that are in comparable growth stages.

Product Leadership

It is lonely at the top of product. Whether you're a CPO, VP of Product, Director of Product or a Heads of Product. We have a group that can add new perspectives to your challenges.

Technical Leadership

We Provide different groups for CTO, VPs of Engineering, Directors of Engineering etc. We separate physical product, physical&software and software groups to make context more alike.

CFOs

Being end responsible for the financials brings specific sets of challenges. From deciding when it is time for cut-backs, to working with that controller that has a black box of excel hell, to your role in the leadership team. There is always opportunity to grow.

And many more!

We are currently growing rapidly. We added partner coaches and they are reaching out to people close to their expertise. Aside from the ones showcased here, you might be approached by one of our partner coaches for a group that serves your specific niche. Have fun!

About Martijn Versteeg

Martijn Versteeg

I love excellence.

With Group Effort, my goal is to nurture and grow a community of top-performing leaders in Tech Companies across Europe. Perhaps I’ll see you there soon! I found that the higher you go, the lonelier it gets.

You need to leverage the experiences of other leaders and companies.

I believe if you want to go far, you go together.

If you’re a product or tech leader done with fluffy talks, vague advice, and generic content overload — we might be a fit.

I have the privilege of looking behind the curtain at 200+ companies across Europe, seeing what makes great leaders thrive (and where others fall short).

I bring those insights to you through curated peer groups, conferences, and tailored support like assessments, off-sites, and training — all built to help you grow faster by learning from those who’ve been there.

Want in but don’t know where to start? Ping me on LinkedIn or contact me with the details below!