Stop going on founder side quests

A structured approach to PMF. Weekly check-ins and a systematic GTM. Backed by my own PhD research.

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Founders I work with got in

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and I helped to get these ideas to market:

Unstuck from zero customers to one hundred

"After working for months on my innovative bike lock, Jeroen helped me to focus on getting my product to market. He held me accountable to doing things that move the needle, and see through the noise. At the end of my collab with Jeroen, I reached 100+ sales, and felt comfortable to continue by myself. With a philosophical tangent here and there, he's helped me to get unstuck and ahead as a founder"

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Charlie

Scoot Boot - Chicago

Bike Lock with 120db alarm

Focus, accountability, and momentum

"You can easily convince yourself a side quest is worth it. Jeroen asks the tough questions to keep your eyes on the prize. He drives velocity through weekly accountability and focusing on the right things. It keeps you away from distractions."

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Yasir

NoSocial - Amsterdam

AI Recruiting platform

Additional brain

"Jeroen is an additional brain. Someone who shares your ambitions, has relevant experience and knowledge, and can provide support at a deeply personal level. Sanity checks when you need them."

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Julia

Badge - Lisbon

Remote work platform

Validate my direction

"Jeroen is my sounding board for strategic decisions. Our calls help me validate my direction, sharpen my ideas, and identify the next improvements. It keeps me moving forward with confidence."

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Menno

Noa - The Netherlands

Intelligent voice for recruiting

Now doing sales calls confidently

"I needed a structured approach to scale my sales calls and tactics for smoother conversations. With Jeroen’s input, I walked into those meetings feeling more confident than ever."

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Philipp

Rollouter - Switzerland

Enterprise hardware management SaaS

Actionable advice with relevant examples

10/10 would recommend. Jeroen helped me get better focus on what's the most important priority. Asks the right questions to dive deep and gives very actionable advice with real examples based on the many startups he worked with.

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Jayson

Marvel - Amsterdam

Agentic AI for insurance

Sanity checks and action points

Jeroen is the best! Helpful insights and sanity checks. Walked away with action points we are excited to execute on. Would recommend for any founder.

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Eric

Ailixr - Hong Kong

Educational AI platform

Learn to think like a startup

"By working with Jeroen, I've learned how to turn big ideas into small experiments. This increased momentum and focus for our startup. We now know what works, without spending 6 months of building it."

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Caroline

Grape Genius - Rotterdam

DuoLingo for wine

Mindset shift to the customer

"He helped me to shift my mind away from what I offer to focus on the customer. From supply to demand. This has helped me to sharpen my value proposition immensely"

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Dylan

Bildung Academy - Amsterdam

Self-development programs for adults

Hard and honest feedback

"Jeroen doesn't beat around the bush. He highlighted what customer information I missed in a direct way, I immediately knew where to focus. That's the kind of feedback I prefer to hear, cold and early."

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Javier

Nummary - Madrid

Investment intelligence platform

350+ startups

mentored for 3 - 14 months

Over 1000 founders

attended my workshops

25+

Accelerator cohorts got my workshops

Examples of my results

Anonymised for discretion

Unstuck hardware founder

Start: Product ready, sales zero, non-existing GTM, weak signs of PMF

End: 100+ sales, GTM strategy clear, beachhead segments identified, signals of PMF emerging through actual use cases. Team more lean, lowered burn-rate.

Duration: 6 months

GTM for AI Startup

Start: AI platform ready, potential customers were not onboarding drastically

End: More effective GTM, outbound reply rate jumped from 0.5% to 30%+. Joined accelerator, therefore ended collab.

Duration: 4 months

From 1000 active users to clear GTM and monetisation strategy

Start: B2C app, many users, fraction paid, scattered GTM and revenue actitivities

End: Clear segmentation and monetization strategy. Clear UX strategy to redesign flow to increase retention and conversion.

Duration: 5 months

Invalidated marketplace idea

Start: Startup idea, product ready, no proof of PMF, GTM not existing

End: After pulling hard, GTM seemed impossible. PMF not there, proposition too good to be true.

Duration: 2 months

From 10.000 products in stock to multiple developed channels with deals

Start: Consumer hardware product with high PMF signals, yet not a scalable GTM motion.

End: Global multiple chanels and sales partners, sales are dripping in, online sales taking off.

Duration: 11 months

Kickstart package

2 hour kick-off + 4 weeks of mentoring to get your show on the road

  • 2 hour kick-off session

    Find focus and clear targets and tactics for the next weeks

  • ICP Refinement

    Clarity on the right market to grow in

  • Positioning and messaging

    Find a simple way to describe what you do

  • GTM strategy validation

    Setting up and refining channels that work (including outreach)

  • Onboarding debugging

    Improve the overall conversion

  • 4 weekly mentoring calls

    Process learnings and sanity check priorities

  • Unlimited DMs

    You can email me or WhatsApp me unlimited questions throughout the week

  • How I increase your momentum

    What we cover in calls

    Priority checks

    I challenge your founder side quests.

    Segmentation clear

    ICP/Beachhead clarity improved.

    Outreach messaging optimisation

    Conversion may go up from 0.5% to 30%.

    Positioning

    Have a clear product position your customers immediately get. 

    Validation tactics

    New perspectives on how to approach blockers.

    Improve sales interview skills

    Help with structure of sales calls and what questions to ask

    Signal sanity check

    When things go slower, I will be honest if it's a red flag or not.

    Intros to my network

    To founders in similar space, experts, and sometimes investors (the last is rare, don't chase me for this).

    Learn about your key features

    What is the value you actually bring? 

    Our Team

    Have you ever seen them in the same room together? 😏

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    Jeroen the Mentor

    Guiding light

    Jack of all trades: Trained as a designer, ex-founder, ex-product-owner, innovator at corporates and now experienced mentor.

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    Jeroen the Scientist

    Researcher of product-market fit

    My PhD focuses on how early-stage founders design their startup. Fringe insights from academia.

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    Jeroen the Energizer

    Battler of downs

    Doing a startup is a rollercoaster. I've coach founders through hard times, focusing on the upside of things.

    Any startup

    As long as it's early-stage

  • Software, AI, Hardware, Marketplaces

    As long as it is techy

  • B2B, B2C or B2G

    Yes, even those pesky governments

  • Worldwide

    Worked with founders from the Americas, Europe, and Asia

  • Three packages

    Discounts available for bootstrapped, pre-revenue startups. Payment in tranches possible.

    1 month kickstart package

    Structure, focus, and get moving

    €1950

    total

    $150per seat per year
    • ICP refinement

    • Positioning & messaging

    • GTM strategy validation

    • Onboarding debugging

    • 2 hour kick-off

    • 4 weekly mentoring calls

    • Unlimited DMs

    • AI summaries of mentoring calls

    • Free access to premium Substack posts

    3 month mentoring package

    Usual time needed to move the revenue needle

    €2800

    total

    $450per seat per year
    • Everything in the kickstart package, plus:

    • Two additional months of bi-weekly check-ins

    6 month mentoring package

    Usual time needed to move the revenue needle

    €3900

    total

    $450per seat per year
    • Everything in the kickstart package, plus:

    • Five additional months of bi-weekly check-ins

    Get a first free consult

    Get to know, vibe check, and some free tactics

    Error

    I will reach out to you for scheduling

    FAQ

    Missing anything? Send me an email!

    Did you ever have a startup?

    Yes, two, and made many mistakes. One never exited the business plan writing phase. The other we built for 1.5 years and then launched, got 1500 downloads, and usage flatlined. We built something people didn't want. 

    What is your PhD on? Can I read some?

    Early-stage startups. I see startups as a design object. I'm investigating how entrepreneurs design successful startups. And nope, our mentoring will not be part of our research—unless we specifically agree to that. My book is finished later this year. I'll post about on my Substack or LinkedIn.

    On non-compete

    I share insights anoumously between startups I mentor. This way, everybody profits from the knowledge I built. If you want me to not work with any of your competitors, you pay five times the regular monthly fee.

    I don't have the resources, do you do equity?

    No, I don't. You don't want me on your cap table for three months of work, trust me. Given the early-stage risk, the equity share I require to make it worthwhile to me is not in your favour. You may pay in tranches, and I offer discounts for pre-revenue, bootstrapped startups.