*By Timothy Jacqmin — Co-Founder, Nexuro Digital · July 2026*
TL;DR
- A good SEO agency isn't chosen on a promise of "rank #1," but on objective criteria: method, transparency, ROI measurement and verifiable references.
- Google is explicit: no one can guarantee a #1 ranking. Any agency that promises one (or claims a "special relationship" with Google) is a red flag.
- Ask five decisive questions: expected results and timeframe, how success is measured, experience in your industry, what is actually delivered, and how you'll communicate.
- Compare billing models (monthly retainer, project fee, hourly) on what they include, not just the sticker price. Avoid "pay per ranking" performance deals.
- A serious agency starts with an honest audit (read-only access to Search Console), documents every action, and ties SEO to your sales (not traffic for traffic's sake).
You're looking for an SEO agency in Belgium. You type the query and land on dozens of pages that all promise the same thing: "explode your visibility," "rank #1 on Google." How do you decide when everyone uses the exact same line?
The truth is that SEO is a market where it's easy to sell a dream and hard to verify the work. An SME owner rarely has the time or the technical reference points to tell a solid agency from a promise vendor. This guide gives you the criteria, the red flags and the exact questions to ask (including the ones Google itself recommends) so you can choose with your eyes open. No "us versus them": just an objective checklist.
Why is choosing an SEO agency so risky?
SEO commits your site for the long term, and a bad agency can do more harm than good. Google explicitly warns that an irresponsible SEO can damage your site and reputation, notably by creating deceptive content or building artificial link schemes that can get your site removed from the index. So the risk isn't only "wasting your budget": it's also harming an asset you own.
The second problem is information asymmetry. You're buying a service you can't technically evaluate, at a point where results take months to appear. In the meantime, it's easy for an agency to bill "reports" while nothing moves on your revenue. The only real protection is an objective selection framework decided before the first sales meeting.
Key takeaway: you remain responsible for the actions of any agency you hire. If an SEO uses prohibited techniques, it's your site that pays the price, not theirs.
What should a good SEO agency actually deliver?
Before comparing providers, you need to know what a competent SEO agency actually produces. A good SEO agency works on three pillars: technical (can Google crawl and index your site?), content (do you answer your customers' questions?) and popularity (do other sites cite you?). An agency that only talks about "keywords" while ignoring the technical side or internal linking is doing a third of the job.
Concretely, the deliverables expected from serious SEO work are:
- A clear initial audit (technical, content, popularity) with an honest baseline and realistic improvement estimates.
- A keyword strategy aligned with your offer and real search intent, not flattering volumes that never convert.
- Documented on-page and technical optimizations (tags, structure, speed, Schema.org structured data, indexing).
- Content production that answers real customer questions, plus coherent internal linking.
- Reporting that is readable, presentable to a management committee, and ties SEO to conversions (leads, sales), not just traffic.
If you want the detail of what a serious diagnosis contains, we described it in our dedicated article on the method behind a complete SEO audit. And to understand the difference between an agency and an individual profile, see the role of an SEO consultant.
What objective criteria should you use to evaluate an SEO agency?
The right reflex isn't to compare agencies against each other by name, but to score each of them on a criteria grid. Here's the one we recommend to a Belgian SME owner.
| Criterion | What reassures | What should alert you |
|---|---|---|
| Method | Audit first, then a prioritized, explained plan | "Let's launch and see" |
| Transparency | All actions documented and shared | Black box, refusal to explain |
| Measurement | KPIs tied to sales (leads, revenue), not traffic alone | Only rankings and traffic volume |
| References | Verifiable client cases, reachable contacts | No concrete example to show |
| Compliance | Follows Google Search Essentials, cites official docs | "Secret" techniques, mass links |
| Contract | Clear commitment, reasonable exit | Long locked-in term, vague penalties |
| Point of contact | One person who knows your business | Rotating contact, generic answers |
The single best criterion is the agency's curiosity about your business: Google advises checking whether the SEO is interested in what makes your company unique, who your competitors are, and how your customers find you. An agency that doesn't ask these questions is selling a standard service, not a strategy.
What questions should you ask an SEO agency before signing?
Your questions are the best filter. Google publishes an official list of questions to ask before hiring an SEO, which we complete here with a few field additions. Ask them all, and above all listen to the clarity (or fog) of the answers.
- Can you show me examples of previous work and share success stories? A serious agency has verifiable references.
- Do you follow the Google Search Essentials? (the former "Webmaster Guidelines"). The answer should be a clear yes, with examples.
- What results do you expect, and in what timeframe? How do you measure success? Avoid week-by-week numeric promises; demand a measurement logic.
- What's your experience in my industry and in my country / city? Belgian local SEO has its own specifics.
- How will we communicate? Will you share all the changes made to my site, with the reasoning behind them? Transparency is tested here.
- How do you bill, and what's included? (see the billing section below).
- What do you base your recommendations on? A good agency cites official Google documentation as evidence, not "secrets."
Common mistake: judging an agency on the polish of its sales deck rather than the precision of its answers to these seven questions. The salesperson seduces; the method delivers.
What are the red flags of a bad SEO agency?
Some signals should make you walk away, no matter how charming the salesperson. The biggest red flag is a guarantee of a #1 ranking: Google states that no one can guarantee a ranking, and recommends being wary of agencies that promise positions or claim a "special relationship" with Google. A guaranteed result on an algorithm no one controls is, at best, ignorance, at worst, a lie.
Other warning signs worth knowing:
- "First page or your money back": it sounds good but means nothing. "First page" on which keyword? They can rank you for a zero-competition query that will never bring you a customer.
- Secrecy: an agency that won't clearly explain what it will do is a risk. Google advises asking for explanations whenever something is unclear.
- Unsolicited emails: a provider that cold-pitches you claiming "your site isn't listed anywhere" deserves the same skepticism as an ad for miracle diet pills.
- Link schemes: "submit to thousands of search engines," mass backlink buying, or being required to link back to the agency. These practices are useless or dangerous.
- Vanity reporting: only traffic and ranking curves, never a word about conversions or revenue.
Key takeaway: an honest agency will also tell you what it can't promise. That's a sign of seriousness, not weakness.
How do SEO agencies bill in Belgium?
There's no single SEO price: there are billing models you need to compare on what they include. The right model depends on your need (a one-off project or ongoing support) and your site's maturity, not on the sticker price in isolation. Here are the market's main models.
| Model | How it works | Right when… | Watch out for |
|---|---|---|---|
| Monthly retainer | A fixed monthly amount for a defined scope | You want ongoing support | Check what the retainer really includes |
| Project / fixed fee | A price for a scoped mission (audit, migration, redesign) | One-off, bounded need | Nail down the scope up front |
| Hourly / day rate | Billed by time spent | Variable needs, ad-hoc advice | Ask for a capped estimate |
| Performance-based | Payment tied to rankings or traffic | Rarely recommended | Pushes toward easy keywords and risky shortcuts |
We won't publish "finger-in-the-air" price ranges here: they depend too much on your industry, your competition and the state of your site. For documented, honest orders of magnitude, see our dedicated article: how much SEO costs in Belgium. And if you're still unsure about the discipline itself, go back to fundamentals with our guide on where to start with SEO.
Recommendation: be wary of "pay only on results." It looks risk-free, but it pushes the agency toward the easiest keywords (and the least useful for your sales), or even toward risky techniques to deliver fast.
SEO agency in Brussels or elsewhere: does local matter?
Many owners look for an "SEO agency in Brussels" out of a proximity reflex. Geographic proximity is a comfort, not a performance criterion: what matters is the agency's experience in your market and its ability to do local SEO. An agency in Liège or Namur can rank a Brussels business perfectly well, as long as it masters local SEO (Google Business Profile, geo-targeted queries, reviews).
That said, Google does recommend asking an agency about its experience in your country and city. The Belgian market has its particularities: FR/NL bilingualism, local competition, specific search habits. An agency that knows this context will move faster. So the real criterion isn't "how far away are you?" but "have you already ranked businesses like mine, here?".
Should you choose an agency that also does GEO?
Your customers no longer search only on Google: they ask their questions to ChatGPT, Claude or Perplexity. A future-proof agency must know how to optimize not just for Google rankings, but also to be cited by generative engines (what's called GEO, Generative Engine Optimization). Google itself now lists "optimizing for generative AI" among the useful services a good SEO can provide.
One caveat: ask whether the agency's GEO/AEO advice is aligned with Google's official guidance on optimizing for AI features. GEO isn't a magic formula separate from SEO: solid, structured, sourced content is the best starting point for being cited by AI. We detailed this shift in our guide on how to be visible in ChatGPT, Claude and Perplexity. It's the ground where we position ourselves as pioneers in Belgium.
Conclusion: choose a method, not a promise
Choosing an SEO agency in Belgium isn't about finding the one that promises the most. It's about finding the one that most clearly explains how it will work, what it will measure, and why. A good agency starts with an honest audit, documents every action, ties SEO to your sales, and isn't afraid to tell you what it can't guarantee.
That's exactly how we work at Nexuro: no overselling, no black box, a single point of contact who knows your business. If you'd like clarity with no strings attached, we can look at the real state of your site together during a free audit of your digital ecosystem. No bots, no salespeople: Timothy or Bryan personally gets back to you within 24 hours.
*— Timothy Jacqmin, Co-Founder, Nexuro Digital*
FAQ
How do you choose a good SEO agency in Belgium?
Score each agency on an objective grid: method (audit first), transparency, how success is measured (sales, not traffic alone), verifiable references and adherence to Google's guidelines. Ask the official questions Google recommends. Walk away from any agency that guarantees a #1 ranking. The right choice is the clarity of the method, never the strength of the promise.
What questions should you ask an SEO agency before signing?
Seven key questions: can you show success stories? Do you follow the Google Search Essentials? What results, in what timeframe, measured how? What experience do you have in my industry and region? How will we communicate and will you share your actions? How do you bill? What sources back your recommendations? The clarity of the answers is your best filter.
Can an SEO agency guarantee the first position on Google?
No. Google explicitly states that no one can guarantee a #1 ranking, and recommends being wary of agencies that promise positions or claim a "special relationship" with Google. The algorithm is controlled by no outside party. A ranking guarantee is therefore a major red flag: look instead for an agency that promises an honest method and honest measurement.
How much does an SEO agency cost in Belgium?
There's no single price: agencies bill via monthly retainer, per project, hourly, or (more rarely, and best avoided) on performance. The right model depends on your need and the state of your site, not on the sticker price in isolation. Compare what each offer actually includes. For documented orders of magnitude, see our article on the price of SEO in Belgium.
Should you choose a local SEO agency in Brussels?
Not necessarily. Proximity is a comfort, not a guarantee of performance. What matters is the agency's experience in your market and its command of local SEO (Google Business Profile, geo-targeted queries, reviews). Google does recommend, however, checking the agency's experience in your country and city, because the Belgian market (bilingualism, local competition) has its specifics.
What are the signs of a bad SEO agency?
The main red flags: a guaranteed #1 ranking, a "first page or your money back" pitch, refusal to clearly explain the work, cold email outreach, mass link schemes, and reporting limited to traffic with no link to conversions. Google also recommends never granting write access to your Search Console for a simple audit: read-only is enough.
Sources
- Google Search Central — *Do you need an SEO? Tips for hiring an SEO* (updated 2026-06-05): https://developers.google.com/search/docs/fundamentals/do-i-need-seo
- Google Search Essentials (official guidelines): https://developers.google.com/search/docs/essentials
- SEOptimer — *10 important questions to ask an SEO agency*: https://www.seoptimer.com/fr/blog/questions-a-poser-agence-seo/
- Markentive — *6 questions to ask before choosing an SEO agency*: https://www.markentive.com/blog/6-questions-a-poser-agence-seo
- Sortlist Belgium — *Comparison of SEO agencies in Belgium*: https://www.sortlist.be/fr/seo/belgique-be
