Companies Using ZoomInfo

Before you compare ZoomInfo's footprint to anyone else's, it is worth being precise about what the number on this page counts. TechnologyChecker.io tracks 29,253 domains running ZoomInfo's visitor-identification tag as of August 24, 2026, and we matched 22,053 of them to a company record. That is a census of WebSights, the script a company puts on its own website to identify the organizations browsing it. It is not a list of ZoomInfo's customers.

Why the distinction matters

Most of what ZoomInfo sells leaves no trace on the open web. A sales team that logs into the platform, filters a market, exports a list and works it through email never touches its own website in the process. Nothing about that customer is visible to us or to anyone else scanning the web. Only the customers who deployed the tag show up here, and deploying it is a separate decision from buying the data.

So treat 29,253 as a firm floor rather than a total. It is an exact count of one thing and an undercount of another. The useful consequence is that everything downstream on this page describes a specific, self-selected group: companies that decided identifying anonymous web traffic was worth paying for.

The tag manager gives away who installed it

The single most revealing number in our data is not about ZoomInfo at all. 91.97% of these domains also run Google Tag Manager, one of the highest overlaps we record for any technology on TechnologyChecker.io. Neither ZoomInfo host appears in the page source of the sites we checked by hand; both are injected at runtime, which is exactly what a tag manager does.

A technology that reaches nine in ten of its installations through a tag manager is not being adopted by engineering teams. It is being pasted in by marketers, which means the buying decision, the rollout and the decision to remove it all sit with the same person.

That explains a great deal about the shape of the base. There is no procurement cycle and no release train standing between wanting the tool and running it, which is why the install base skews so far towards smaller companies and why churn in this category is quick in both directions.

Who actually buys visitor identification

Enterprise buyers are not the story. 83.06% of identified customers employ fewer than 200 people and only 4.70% employ more than 1,000. The largest single band is 11 to 50 employees at 35.76%. Geographically the base is concentrated to an unusual degree, with 78.84% in the United States and better than nine in ten across the United States, United Kingdom and Canada together.

By industry, roughly a fifth sell technology to other businesses, with Software Development at 11.90% and IT Services at 8.93%. Advertising Services follows at 4.00% and Staffing and Recruiting at 3.70%. What unites the list is deal shape rather than sector. These are businesses where a sales cycle runs for weeks, a single customer is worth pursuing by name, and a handful of anonymous visits a week is a tractable number of leads to chase. Consumer retail is close to absent, which follows: naming the company behind a visit is worthless when the visitor is a private shopper.

The stack tells the same story from another angle. HubSpot appears on 40.66% of these domains against Salesforce's 10.44%, a four-to-one split that runs opposite to the enterprise-heavy picture you would get from ZoomInfo's own marketing. Salesloft appears on 3.39% and Qualified on 3.45%, the tooling of a team running outbound rather than one managing a large field organization.

The category table is measuring two different businesses

ZoomInfo ranks 5th of 50 in Visitor Identification with 10.13% share, and that ranking needs a caveat we would rather state than bury. Three of the four technologies above it are not competitors in any commercial sense. FingerprintJS is device fingerprinting for fraud prevention. ipapi.co and ip-api are general-purpose IP lookup services that websites call to set a currency or a language. They share a detection surface with ZoomInfo, not a market.

Strip those out and the real contest is with Leadfeeder at 36,312 domains and Leadinfo at 23,134. Our migration data makes that concrete: over the period we observed, 106 domains dropped ZoomInfo while running Leadfeeder, and 79 went the other way. That is the only genuinely two-way movement in the category, and on these windows it runs slightly against ZoomInfo. The trade buyers are weighing is a focused, cheaper tool against a tag that arrives attached to the contact database you would use to act on what it finds.

What 9,112 reviewers agree and disagree about

ZoomInfo holds 4.5 out of 5 on G2 across 9,112 reviews, and the sentiment breakdown contains a contradiction worth sitting with. Data accuracy is the third most-cited strength, with 324 reviewers naming it. It is also, comfortably, the dominant complaint: the five leading criticisms are inaccurate records, stale data, contacts who have moved on, wrong locations and outdated job titles, totalling 910 mentions between them.

When accuracy is simultaneously the third-best thing and the five worst things about a data product, the honest reading is that quality varies sharply by segment. Buyers should test coverage on their own target list before signing, not on a vendor-supplied sample.

That is not a reason to dismiss the product. It is the predictable condition of any business selling contact data at this scale, where records decay every time somebody changes job. It is a reason to treat a trial as a measurement exercise on the segment you actually sell into.

How to read the August step in the chart

The usage chart shows a steep rise between July and August 2026. That step reflects changes on our side, both the domains we cover and the signals we detect ZoomInfo with, rather than a surge in adoption. Over the same two months our overall detection volume across all technologies fell, so no market-wide event moved anything four-fold. The section of the chart that describes genuine adoption is the steady climb from 2020 through 2024, when the tag went from a few hundred domains to several thousand.

One further caveat applies to any script-based count, including this one. We verified a sample of these deployments in a real browser rather than by fetching the page source, because the tag only appears once JavaScript runs. On a handful of sites that our records list as active, the tag did not fire during our check at all, most likely because it waits for cookie consent. Consent-gated tags are a genuine source of undercounting across this whole category, and they push the true figure up rather than down.