I improve the conversion rate of websites, online shops and apps across Europe.

CRO agency in Brussels. You have the traffic, I do what it takes to convert it.

A free audit, then ongoing support where every change is measured.

Get your free audit
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5/5 on Google, 3 reviews

Sébastien Balieu, your personal contact from start to finish.

  • Slow page
  • Form too long
  • Unclear message
  • Missing button
  • Hidden fees
  • No customer reviews
  • Account required
  • Price not shown
  • Intrusive pop-up
  • Unreadable on mobile
  • Too many choices
  • Delivery too expensive
  • Payment declined
  • Jargon
  • Confusing menu
  • 404 error
  • Captcha
  • Unknown lead times
  • No guarantee
  • Broken tracking
  • Vague promise
  • Oversized images
  • Hidden contact details
  • Buried button
  • Cookie banner
  • Off-target traffic
  • Emptied basket
  • No promo code
  • No returns
  • Dead link
  • Sign-up too long
  • App crashes
  • Required fields
  • Generic campaign page
  • No proof

I clear the blockers that stop your visitors from converting

Blockers cleared 00

My clients trust me with their platform, and I take it personally
EuronetNallianTraxxeoRepos ProductionHeat MeVaibesHighcodataCatIDDogIDHR-AlertCawab
You know it

Something's off.

You have already paid for every visitor who leaves without doing anything, through advertising or search.

  1. I have visitors, but too few enquiries

    The journey to the enquiry

  2. I get contacts, but few are relevant

    The message and the targeting

  3. I have full baskets that never reach payment

    The checkout

  4. I have campaigns that barely convert

    The landing pages

  5. I've had fewer enquiries since the redesign

    The familiar cues lost in the redesign

  6. I have users, but few customers

    The move to the paid plan

Recognise yourself in one of these situations?

Get your free audit
Case studies

Three sites redesigned to convert.

All case studies
The method

The CRO method: analyse, improve, repeat.

Revenue = traffic × conversion rate. I take care of the conversion rate.

  1. Step 130 min · free

    The audit

    Within 48 working hours, you receive around ten blockers ranked by impact, each with a screenshot and the proposed fix. We go through them together in 30 minutes. The document is yours to keep, whether you work with me or not.

  2. Step 21 to 2 weeks

    Data first

    I check that your analytics tools count conversions correctly. Then I watch how your visitors behave: heatmaps, session recordings, funnels. These starting figures are what I measure every change against.

  3. Step 31 meeting

    Priorities

    I rank my improvement hypotheses by their possible effect on your revenue, how certain I am of them and the work they need on your stack. Then we choose the first project together.

  4. Step 42 to 6 weeks

    Implementation

    I design the improvements (UX, content, forms). My partners and I build them, or I work with your team. If there is enough traffic, I validate them with an A/B test.

  5. Step 5After 4 to 6 weeks

    Analysis, then round again

    I measure how your conversions and your revenue have moved. Did it work? Good. If not, I start again with more data.

The first step commits you to nothing.

Start with the free audit
I have one goal

Improve the conversion rate of your website, your online shop, your app.

My commitments

You know what to expect.

These commitments apply from our first conversation, before anything is signed.

  • The audit is useful, even if we go no further

    A written document within 48 working hours, which you keep. Your team can apply it on its own.

  • If the problem lies elsewhere, I tell you

    It can come from the offer, the traffic or the market. In that case, I don't offer you ongoing support.

  • No forced redesign

    I fix the existing site first. I suggest a redesign only when the site can no longer evolve.

  • Every change is measured, failures included

    You see the changes that moved your conversions, and the ones that achieved nothing.

  • I do the audit myself

    I analyse your site myself and remain your contact until the final review.

  • Not sure yet? Start with the audit, it's free.

    Get your free audit

I'm Sébastien, founder of Numinam.

After working in marketing at Walibi and Zetes, I founded Numinam and co-founded Coddy. I also build and sell my own products.

I carry out the diagnosis and remain your contact for the whole engagement. For implementation, I rely on a network of partners, each with their own speciality, and I work with your team.

My background
Sébastien Balieu

Sébastien Balieu

Founder of Numinam, co-founder of Coddy

Get your free audit

  • 15 years

    of CRO experience

  • Expert

    in UX / UI

  • Full-stack

    developer

  • AI

    evangelist

5.0 out of 5

3 Google reviews

"Numinam's contribution to the development of our App has been significant in its success…"Stephane Draux, Spengo"Numinam (One More Pixel) is doing a fantastic job for Euronet. They’ve started the…"Valérie Van Belle, Euronet"At Nallian we build solutions that are trusted by the world's leading airports, ground…"Jean Verheyen, Nallian"The new website much better reflects who we are. It tells our story more clearly, it's…"Joke Aerts, Nallian"Numinam's technical and design vision has enabled us to improve our lead generation…"Jérôme Van De Sande, Heat Me"Numinam has completely modernized our website. The design is clearer, more credible, and…"Olivier Lafosse, Heat Me"It was a real pleasure to do business with Sebastien. He did a great job and transform…"Shirley Boterdael, Highcodata
Testimonials

Over to my clients.

Nallian · Redesign
Heat Me · UX
FAQ

Answering your questions is my job.

Yes, with no commitment, if your project fits the support I offer. You come away with the main blockers identified and a first lead for each one. If you want me to fix them, that is a paid engagement.

Within 48 working hours. You receive a written document listing around ten blockers, each with a screenshot, its likely cost and the proposed fix. Then we go through it together on a 30-minute video call.

I can observe journeys and gather user feedback. A/B tests need enough conversions. With little data, I explain how far the conclusions can go.

I define the metrics before changing the journey, then I track how they move. Campaigns, prices and seasonality are taken into account. A before/after comparison is not enough to prove the effect of a change.

Me, your team or a partner, depending on the quote. I take charge of the agreed deliverables, without guaranteeing an increase in sales.

Yes. I can design the fixes and work with your agency on building them in. Responsibilities are set before we start.

B2B or B2C companies whose website, online shop or app already contributes to revenue. The project has to make economic sense and be feasible to implement.

I tell you. The offer, the traffic or the market can explain why things have stalled. The audit does not automatically lead to a sales proposal.

The budget depends on the project and on how much of the implementation you hand over to me. The quote sets out the deliverables, the planned capacity and the terms before you commit.

I'm based in Brussels and work remotely, in France as well as Belgium.

Can't find your question?Ask me directly

Free CRO audit

Want to see your site's blockers?

Send me the address of your website or app. Within 48 working hours, you receive around ten blockers ranked by impact, with the proposed fix for each.

Get your free audit