Sistrix Visibility Index: Whose Number Is It?

The Visibility Index comes from SISTRIX, a German SEO software company based in Bonn. According to the company's own documentation, its time series for the German market goes back to February 2008, making Germany one of the longest-tracked markets the tool has. It's a proprietary, in-house metric. Google doesn't calculate or publish it, and no other search engine does either.

What matters most here is where the data comes from: SISTRIX doesn't measure links. The company crawls Google's search results itself for a fixed set of keywords per country and logs which domain ranks in which position. Those ranking observations, not link profiles, form the basis of the index. That's the fundamental difference from metrics like Domain Authority or Domain Rating, both calculated from link indexes, covered in more detail in the last section below.

Per its own documentation, SISTRIX collects search results for roughly a million keywords per country, chosen to form a representative cross-section of that market's search volume. The Visibility Index is now available for more than 50 countries, though update frequency varies: daily in 13 countries, weekly in the rest. The German-speaking region remains, both historically and by design, the core of the product, even as international coverage has expanded over the years.

For each of those roughly one million keywords per country, SISTRIX pulls the organic top-100 Google results; paid ads aren't included. That works out to roughly 100 million data points per country as the calculation base. Every ranking found is then weighted by three things: the exact position in the results, the estimated search volume for that keyword, and the expected click-through probability at that position. SISTRIX also names search intent as a factor, since users with a clearly navigational intent tend to click only the first result, while broader informational queries see clicks further down the list more often.

This domain-wide, global figure shouldn't be confused with so-called project visibility inside the SISTRIX Toolbox, where a customer can define their own keyword list for a specific project. Both values carry a similar name and share the same general calculation principle, but they draw from different keyword pools, a fixed set defined by SISTRIX for the domain-wide index, a freely chosen list for project visibility.

An example from the company's own documentation makes the principle concrete: position eight on a heavily searched term earns more points than position one on a rarely searched one. Overall, SISTRIX describes distributing a fixed pool of 100,000 visibility points across every domain found in a given market. Any single domain only ever captures a fraction of that total, a point the closing section below returns to, because it matters for comparing this number against other metrics.

What SISTRIX doesn't disclose: the exact keyword list, the precise weighting formulas and the specific CTR values per position all stay a trade secret. The company confirms only that "a portion" of those keywords gets swapped out periodically to reflect shifting demand, without stating an interval or a percentage. Anyone hoping to reverse-engineer one exact domain value can't, not with what's publicly documented.

The Visibility Index isn't a Google ranking factor. Google doesn't use it in its own algorithm and, in a technical sense, doesn't even know it exists, since it's generated entirely outside Google. A number going up or down doesn't directly change how Google ranks a site, it simply describes the measured outcome of that ranking.

It's also not a link metric, which is the central difference from Domain Authority, Domain Rating or Authority Score. Those three estimate a domain's authority from its backlink profile, while the Visibility Index measures actually observed ranking positions. A domain can carry a strong backlink profile and still show a low Visibility Index if it simply doesn't rank well for the keywords in the tracked set, and the reverse holds too.

And it's not a direct traffic measurement. SISTRIX states this explicitly in its own documentation: the Visibility Index is not a traffic index and doesn't aim to be one, it measures SEO success, not visitors to a website. Visibility correlates with traffic, since better positions tend to draw more clicks, but that conversion runs through estimated, not measured, click-through rates. Snippet design, brand recognition or seasonal effects can all move real traffic without the visibility figure shifting at all.

SISTRIX also flags that updates aren't real-time for most countries, which get measured weekly rather than daily. That's a technical limit of the methodology itself, not a broken promise from the company.

It works best as a time series for a single domain: a drop from one week to the next, measured with the same methodology, is a real signal that something has shifted within the Google results SISTRIX tracks. That's precisely what it's built for, and the company itself describes how it helps narrow down the causes of a ranking shift by removing external noise such as differing measurement methods between tools.

It also works reasonably well for comparing competitors within the same market and language: two domains targeting the same country, measured against the same keyword set, start from the same conditions, so their relative movement carries real information. Data depth runs deepest across the German-speaking region, where SISTRIX has measured longest, which gives sturdier historical comparisons there than in markets added later or tracked at a lower frequency.

It's far less useful for comparing entirely different countries or languages. Each market runs on its own keyword set, its own search-volume distribution, and sometimes a different update frequency, so a German figure and a Spanish figure for the same brand aren't directly comparable just by sitting side by side. SISTRIX itself notes that roughly 15% of all Google searches have never been made before, meaning full coverage with any fixed keyword set is structurally impossible. And comparing a value against another tool's visibility index leads to the same trap: the company states plainly that every tool has its own characteristics and that values don't translate one to one across providers.

The most common mistake with this term is placing the Visibility Index next to Domain Authority, Domain Rating or Semrush's Authority Score, as if all four were variations on the same idea. They aren't. The latter three are authority, or link, metrics: they estimate how much weight a domain carries based on its backlink profile, calculated from the number and quality of referring domains. None of them checks whether that domain actually ranks for anything.

The Visibility Index does the opposite: it measures real, crawled ranking positions against a fixed keyword set and ignores link data entirely. That isn't a matter of degree, it's a difference in category. A domain with an excellent link profile can still rank poorly across the tracked keyword set, say because its content or technical foundation is lacking, and would then show a low Visibility Index alongside a high Domain Authority.

The scale differs fundamentally too, something rarely spelled out: Domain Authority, Domain Rating and Authority Score all run on a capped 0-to-100 scale. The Visibility Index has no such ceiling, SISTRIX describes distributing a fixed pool of 100,000 visibility points across every domain found in a market, and any single domain usually captures only a small slice of that total. Two figures that happen to look similar, say a Visibility Index of 40 and a Domain Rating of 40, share no arithmetic relationship whatsoever.

In practice, that means explaining why a domain with a strong Visibility Index shows a weak Domain Rating, or the other way around, isn't a puzzle. They're two tools answering different questions: how much weight does this domain's link profile carry, versus how often and how well does this domain actually rank on Google right now, measured against a fixed keyword set. The two answers can move independently of each other.

SISTRIX didn't start as a software project, it started from a practical problem. Johannes Beus founded the company in 2004, first in Kassel as an SEO consultancy, before it moved to Bonn in 2005, where it's still based. According to a retrospective on the company's own blog, the standard method of the time couldn't reliably show a client whether a site was actually improving: checking a handful of keywords by hand produced, in Beus's own words, "too few, occasionally wrong" position values, nothing solid enough to build a claim on.

That gap led to a 2007 prototype that automatically pulled the top-100 Google results for 1,000 keywords. Official data collection for the Visibility Index began on February 25, 2008, and the SISTRIX Toolbox followed as a standalone product that October. The industry context at the time, per the same retrospective, was an SEO scene still shaped by questionable tricks, keywords hidden in white text on a white background among them. The Visibility Index set out to answer that guesswork with a verifiable number instead.

What began as an internal tool for the consultancy's daily work grew into a product in its own right: the internal question "is this site ranking better than last week?" turned into a metric now used far beyond the German-speaking region, even though that's still where the historical data runs deepest.

SISTRIX started treating AI search as its own area in 2025, not a footnote. Per an update on the company blog covering the first half of 2025, Google's AI Overviews rolled out first in the UK at the end of 2024 and, by the time of that post, already appeared in more than 15% of the queries SISTRIX tracked. SISTRIX responded with a keyword filter called "AI Overview – with ranking," a dedicated AI Overviews section under its SERP reporting, and a SERP archive storing the full content alongside cited sources.

Alongside that, the company launched "SISTRIX for AI/chatbots," still in beta per its handbook page, dated 08/06/2025. It covers ChatGPT, Gemini, and DeepSeek, not Perplexity as a primary platform. Per its own documentation, it draws on roughly 10 million selected prompts per language, split across German, English, French, Spanish, and Italian, producing its own AI Visibility figure, distributed across 1 million points per language and chatbot, using the same underlying principle as the classic Visibility Index.

It's also tracking Google's new AI Mode, which the blog describes as an optional US-only test phase. SISTRIX states it's already working on making that mode measurable, since impressions and clicks for it aren't yet broken out separately in Search Console. In May 2026, per the company's own account, SISTRIX used its AI Visibility figure to document a core update inside ChatGPT, an early sign the company is carrying its methodology over to changes in chatbot answers, not just Google rankings.

Where it genuinely earns its keep is as an early-warning system for a single domain: a drop from one week to the next reliably shows that something shifted in measured Google visibility, whether the cause is an algorithm update, a technical issue, or a content problem. It also holds up well comparing two domains within the same market and language, since both get measured under identical conditions. Within Germany, Austria, and Switzerland, the index gives the sturdiest comparisons, thanks to the measurement history running back to 2008.

Where it falls short is anything outside that narrow frame. Comparing different countries breaks down over differing keyword sets and update frequencies. It's no substitute for traffic either, since it measures ranking positions, not visits. And comparing the figure against another SEO tool's visibility index leads nowhere useful, since every provider runs its own keyword set and its own formula.

What the Visibility Index never delivers, by design, is any read on a link profile. SISTRIX measures rankings, not backlinks; anyone needing to assess link profile strength, say before buying a domain or checking for spam, reaches for a complementary tool like Majestic or Ahrefs. The two categories don't compete, they answer different questions.