SEO agency Onder

SEO is the foundation of your website and sup‎ports your online marketing mix

Onder is a specialist SEO agency based in Zwolle. We ensure that your business appears in Google search results and is mentioned in AI responses from ChatGPT, Gemini and Perplexity. We achieve this through a single integrated approach that combines technical SEO, content, digital PR and GEO. You remain in control thanks to pre-agreed objectives and clear reporting.

Check out the online GEO training course
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SEO & GEO specialists

We are a specialist SEO agency and focus 100% on search engine visibility and AI models. This is reflected in our clear advice and smart suggestions.

Collaborate

Pleasant cooperation is important to us. We are involved, thoughtful and proactive. And are happy to share our knowledge with you and your team.

Personal

We like a personal approach. We have a no-nonsense attitude and are always honest and transparent in our working methods and services.

Free live SEO/GEO analysis

Are you curious to know how your website is performing in search engines and LLMs?

Live SEO/GEO analysis

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Services

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Any questions?

Do you want to know more about SEO? Could your website use a new boost?
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Most recent blogs

All about SEO
GEO starts with your target audience

GEO starts with your target audience (not your prompts)

19-10-2026 Other Martijn Hoving

“How do we fare in ChatGPT?” We’ve been asked that question quite often in the past. But the question is becoming more sophisticated, and the answer doesn’t start with ChatGPT. It starts with the person asking the question. In this article, you’ll read about how we move from target audience to prompts to measurement. GEO (or AI SEO): the question is becoming more sophisticated The question “How are we performing in ChatGPT?” has been asked of us quite often in the past. But we’ve noticed that in all

SEO recovery following a drop in website traffic

SEO recovery following a sharp drop in website traffic

5-8-2026 Migration, SEO & GEO Leanne la Faille

Has your organic traffic suddenly dropped? Naturally, you’ll want to recover it as quickly as possible. The good news is that, depending on the cause, a large proportion of the lost traffic can often be recovered. But to do so, you need to know what the problem is. In this article, you’ll learn how to identify the cause of a drop, what to check in Google Search Console, and what SEO recovery looks like following a migration or Google update. Navigate to: Step 1:

B2B pitfalls that mean SEO is not delivering enough

B2B pitfalls that mean SEO is not delivering enough

2-7-2026 B2B SEO Leanne la Faille

Are you investing in SEO, but not seeing that translate into better leads? That usually doesn’t mean that SEO ‘doesn’t work for your sector’. B2B customers search, compare and make decisions differently to consumers. In this article, we discuss the five biggest pitfalls in B2B SEO and reveal where the opportunities for organic growth actually lie. B2B SEO pitfalls in a nutshell Why B2B SEO works differently With B2B SEO, it’s not just about being found. It’s about

This is us!

A team of SEO specialists

Our team consists of enthusiastic SEO specialists who are happy to work with you for the best results.

Meet our team
SEO agency Onder

Testimonials

Photo by Person of review

Lotte van de Wetering

Advocaat

I’ve been working with Onder for about a year now, and I really should have done so much sooner. I thought I could manage everything myself with SEO, and that went quite well, but since I’ve been working with Onder, my website’s search visibility and conversion rates have increased dramatically. Jan Willem is a true professional who really gets to grips with your business and therefore knows exactly what works. On top of that, I simply have a great deal of confidence in Onder. I’ve had some very bad experiences with other online marketing companies, which is why I actually wanted to keep doing everything myself. I’m glad I decided to outsource my SEO after all. It’s better for my business and it also gives me peace of mind, knowing that my website is in very good hands.

A man with a short grey beard and dark hair, smiling in an office setting.

Daan de Haan

Homie partner - Periscoop

At first I thought: just another one of those SEO sort of places. But at Bureau Onder, I soon realised that things work differently there. I genuinely feel that it’s making me smarter too. Sanne and Ivo produce clear, concise reports for our clients, based on objectives we agree on together in advance. No vague talk about clicks and rankings, but insight into what’s happening, why it’s happening and where the opportunities lie. In addition, there are webinars where they actively share their knowledge and make SEO accessible and practical. That’s perhaps what I find most impressive: Bureau Onder doesn’t just carry out the work; they involve you in what they’re doing. As a result, not only do the results improve, but so do we.

Photo Marleen Spikker, at testimonial for SEO office Onder

Marleen Spikker

Contentmanager corporate websites

Bureau Onder helped us with a specific SEO issue. After several meetings, we came up with a concrete plan of action with the end result being a solid and very comprehensive advice that included all SEO disciplines. A valuable concrete document that we could immediately start working with, as we wanted. We experienced the contact with Martijn, Jeroen and Britt as pleasant and approachable; these experts are an absolute added value for your website.

Marcel Wallage

Eigenaar

The SEO world is full of self-appointed gurus. Some know better than others. Not infrequently, they crack each other down and sell new services or sites. So the key is to find a good supplier... In this search, Martijn was referred by another company. Martijn is a breath of fresh air in this world. Modest, a thinker, finally a consultant who does not make empty promises. The whole process takes time, money and patience. After several months, there were sufficient results. We are happy to recommend Martijn to companies, who want serious onder support in their SEO policy.

image review zehder

Marieke Schulenburg

Projectleider Marketing & Online lead

" During the migration of our website, we enlisted the help of Onder, which proved to be a good choice. They advised and supported us throughout the process, and this resulted in us seeing our organic positions return quickly after the migration and not having to sacrifice much on our SEO traffic. Super! In addition, the whole team is a bit wiser through two interactive training sessions, one around SEO by Ineke and one around GA4 by Cynthia. Very valuable. In short, looking for a nice and good SEO party? Then Onder is the right place to be for you. "

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