Does website visitor identification actually work?
It names some of your visitors. How many comes from the vendors' own figures, and none of the vendor pages we checked says how often the names are right. Visitor identification tools put a script on your site and try to match anonymous visits to companies and people. RB2B, which says over 100,000 websites use it, and Warmly both sell this. Their own pages put the share of visitors they identify anywhere between 15% and 80%, depending on the page, the plan and whether company-level matches are counted.
We looked for an independent accuracy study with a published method and could not find one we were able to open and check on 20 October 2026. So every coverage or accuracy figure below is a vendor's own claim, labelled as such. What can be checked is how the tools work, what they cost, how to test them on your own traffic, and which privacy rules apply.
How does website visitor identification work?
Vendors describe two methods: matching a visitor's IP address to a company, and matching cookies, device data and IP addresses to a database of named people.
| Method | How the vendor describes it | What you get | Where it works |
|---|---|---|---|
| IP-to-company (company level) | Warmly says traditional tools match IP addresses to companies. RB2B uses Demandbase's reverse-IP lookup network for its company-level ID. | A company name and company data, with no named person | RB2B: company-level ID is global on every plan |
| Identity matching (person level) | RB2B matches visitors against a publisher network using first- and third-party cookies, device IDs and IP addresses. Warmly's pixel captures the IP address, device fingerprint, browser metadata, referrer, UTM parameters and page path, then cross-references more than 220 million contact records. | A name and LinkedIn profile; business email on some plans | RB2B: US visitors only |
Both methods have limits that follow from the vendors' own descriptions. Warmly says traffic from known business IP ranges identifies at higher rates than traffic from residential IPs or mobile devices. RB2B's compliance page says its person-level database only contains profiles matched to US home addresses, and that it uses IP ringfencing to resolve only US traffic. A visitor the vendor holds no identity data for can't be matched to a name, however long they stay on your pricing page.
How accurate is it? What RB2B and Warmly claim
The figures RB2B and Warmly publish on the pages we checked are coverage or identification rates: the share of visitors they put a name to. None of those pages says what share of the names were correct. Here is what each page claims, as of 20 October 2026:
| Vendor page | Figure the vendor gives (our summary) |
|---|---|
| RB2B pricing table | Person level (US only): 15-20% coverage on Starter and Pro, 35-45% on Pro+. Company level (global): 15-20% on Free, Starter and Pro, 35-45% on Pro+. |
| RB2B FAQ | 70-80% of website traffic identified when person- and company-level ID are combined; customers typically see 30-40% at person level (US only) and another 30-40% at company level. |
| RB2B 'Who are you' page | Identifies up to 80% of US-based anonymous site visitors, at person and company level. |
| Warmly visitor identification page | Person level: 15-30% identification rate on typical B2B traffic. Company-level identification typically achieves 30-60% match rates on B2B traffic. |
| Warmly data quality page | 95%+ deliverability on verified emails. |
RB2B's own pages give different numbers. Its pricing table shows 15-20% person-level coverage for the $79 Starter and $149 Pro plans, while its FAQ says customers typically see 30-40% at person level. The two may measure different things, since one describes plan tiers and the other typical customer results, but the pricing page does not define coverage. Warmly's 95% figure is about whether emails are deliverable, which says nothing about whether the right person was named.
The number you need is correctness: of the people a tool names, how many actually visited. You can measure it yourself during a free trial.
What does website visitor identification cost?
RB2B starts free and its paid plans start at $79 a month; Warmly starts at $10,000 a year billed annually, or $4,875 a quarter billed quarterly. Prices from each vendor's own page, checked 20 October 2026:
| Plan | Price | What's included | Per included resolution (our arithmetic) |
|---|---|---|---|
| RB2B Free | $0 | Company-level ID only, pushed to Slack, 150 resolutions a month | $0 |
| RB2B Starter | $79 a month | Person-level ID (US only), LinkedIn URLs to Slack or Teams, no email addresses, 300 resolutions a month; 45¢ per extra resolution | About 26¢ ($79 ÷ 300) |
| RB2B Pro | From $149 a month | Business email addresses and all integrations, from 600 resolutions a month; 25¢ per extra resolution | About 25¢ ($149 ÷ 600) |
| RB2B Pro+ | From $199 a month | Premium Resolution with Identity Graph Waterfall, from 600 resolutions a month; 25¢ per extra resolution | About 33¢ ($199 ÷ 600) |
| Warmly AI Web-Deanonymization | From $10,000 a year billed annually, or $4,875 a quarter | Website visitors (contacts and companies), ICP filtering, real-time and Slack alerts, lead routing, CRM sync | Not published |
RB2B defines a resolution as one identified website visitor that it delivers to you. Every RB2B account starts with a 7-day full-featured trial, with no credit card required, which is long enough for the test in the next section. On Warmly, quarterly billing adds up to $19,500 over four quarters (4 × $4,875), compared with $10,000 a year on annual billing, a bigger gap than the 30% annual saving the page advertises, so confirm the quote with Warmly; its GTM Signals Package add-on costs another $10,000 a year.
How do you test visitor identification on your own traffic?
Test it against visitors whose identity you already know, during the free trial, before you pay.
Build a list of known visitors
Before installing, list 20 to 30 people who will visit your site in the next week and whose identity you can confirm: teammates on home and office connections, customers who log in, people who book a demo, and prospects you send a link to. Note where each person is based, since RB2B only names people in the US.
Install the script and send alerts to one channel
Add the script to every page and route every alert to a single Slack channel. Leave filters off for the first week so you see the raw output.
Score coverage and correctness separately
Coverage: known visitors identified, divided by known visitors. Correctness: identified names that match the real visitor, divided by all identified names you can check. A tool with high coverage and low correctness sends your outreach to people who never visited.
Count the matches worth contacting
From everyone identified in the week, count the people who fit your customer profile and write the first message you would send each one. Multiply that count by four for a rough monthly figure.
Decide on the cheapest level that works
If you only need to know which accounts are active, company-level ID may be enough. Pay for person-level ID only if correctness on your own test is high enough that you would trust a name before writing to them.
Which privacy questions should you ask before installing it?
Ask where the identity data comes from, whether your visitors must consent, and what your privacy policy has to say; the answers depend on where your visitors are. What follows summarises regulators' guidance and is not legal advice.
- UK. The ICO's guidance on storage and access technologies (last updated 29 April 2026) says PECR applies to cookies, tracking pixels, fingerprinting techniques, and scripts and tags that store or access information on a user's device (what the rules cover), and allows them in particular circumstances or with the user's valid consent. Its chapter on how to comply puts the duty on the site: "As the online service provider, it is your responsibility to understand the technologies you intend to use and ensure you comply with PECR."
- EU. The European Data Protection Board's Guidelines 2/2023 (version 2.0, adopted 7 October 2024) note that Article 5(3) of the ePrivacy Directive allows storing or accessing information on a user's device only with consent or where necessary for specific purposes. On tracking based on IP only, they say that unless an entity can ensure the IP address does not come from a user's device, it has to take all the steps Article 5(3) requires; whether consent or an exemption applies has to be assessed case by case.
- California. The California Privacy Protection Agency says the CCPA applies to for-profit businesses doing business in California that meet any one of three thresholds: $26.625 million or more in annual gross revenue (effective 1 January 2025), buying, selling or sharing the personal information of 100,000 or more California residents or households, or earning 50% or more of revenue from selling or sharing it. The CCPA's privacy rights also cover California residents who are contacts for business customers, vendors or independent contractors. Businesses that sell or share personal information must honour opt-out preference signals such as Global Privacy Control, and in most instances must also put a clearly labelled opt-out link on their website, such as "Do Not Sell or Share My Personal Information".
RB2B's own pages address some of this. Its GDPR page says customers using its global IP-to-company identification must use a consent management solution. Its compliance page says California law requires website disclosures that you are sharing personal information, meaning cross-context behavioural advertising, and lists its own service as an example. It also suggests privacy policy wording and an opt-out link.
Questions to put to any vendor before you install:
- Where does your identity data come from, and what did those people agree to? Can we see the data usage terms and DPA?
- What does your script collect: cookies, device IDs, fingerprints, IP addresses?
- Can it stay off until a visitor accepts our consent banner, and can we limit it to the regions we choose?
- What should our privacy policy say, and what opt-out do you offer visitors?
- How long do you keep data about our visitors, and how do we delete one person's data on request?
- Under the CCPA, does using your tool count as selling or sharing, and which thresholds do we meet?
What should you do with an identified visitor?
Treat an identified visit as a reason to check fit, then write as you would to any well-researched prospect. Check the person against your customer profile, look at what they have posted recently, and lead with the problem the page they read is about. Leave the visit itself out of the message: the person never told you who they were. Our guide to buying signals for small teams has first lines for other triggers.
Visitor identification only covers people who already reached your site. Public signals cover people who haven't yet: someone posting about the problem you solve, comparing tools, or engaging with a competitor's posts. Siela's AI SDR finds leads from signals like these on LinkedIn and X, scores each one hot, warm or cold with a one-line reason, and saves them to its built-in CRM with the reason they were picked. Used together, a site visit tells you an account is warm, and a public post tells you what the person cares about.
Frequently asked questions
Is website visitor identification legal?
It depends on where your visitors are and what the tool collects. In the UK, the ICO says PECR covers cookies, tracking pixels, fingerprinting and scripts that access a device, which are allowed only in particular circumstances or with valid consent. In California, the CCPA gives residents, including business contacts, a right to opt out of sale and sharing. This is not legal advice.
What is the difference between company-level and person-level visitor identification?
Company-level identification matches a visitor's IP address to an organisation, so you learn which company visited but not who. Person-level identification matches cookies, device data and IP addresses against an identity database to name the individual. RB2B offers company-level ID globally and person-level ID for US visitors only. Warmly reports lower rates at person level (15-30%) than at company level (30-60%).
How much does Warmly cost?
As of 20 October 2026, Warmly's pricing page lists its AI Web-Deanonymization plan from $10,000 a year on annual billing, or $4,875 a quarter on quarterly billing. It includes website visitors at contact and company level, ICP filtering, alerts, lead routing and CRM sync. The GTM Signals Package add-on, covering intent, hiring and funding signals, costs another $10,000 a year.
Is there an independent accuracy study of RB2B or Warmly?
We could not find one that we were able to open and check on 20 October 2026. The figures in circulation, such as RB2B's 15-20% or 35-45% coverage depending on plan, or Warmly's 15-30% person-level identification rate, come from the vendors' own pages and measure how many visitors get a name, not how many names are correct. Testing on visitors whose identity you already know is a practical alternative.
What is a resolution in RB2B pricing?
RB2B defines a resolution as one identified website visitor that it delivers to you. As of 20 October 2026, the Free plan includes 150 a month at company level only, Starter includes 300, and Pro and Pro+ start at 600. Extra resolutions cost 45 cents each on Starter and 25 cents on Pro and Pro+.
Sources
- RB2B pricing (checked 20 Oct 2026)
- RB2B FAQ (checked 20 Oct 2026)
- RB2B: Who are you? (checked 20 Oct 2026)
- RB2B: GDPR (checked 20 Oct 2026)
- RB2B: Compliance (checked 20 Oct 2026)
- Warmly pricing (checked 20 Oct 2026)
- Warmly: Website visitor identification (checked 20 Oct 2026)
- Warmly: Data quality (checked 20 Oct 2026)
- ICO: Guidance on the use of storage and access technologies (last updated 29 Apr 2026; checked 20 Oct 2026)
- ICO: What are storage and access technologies? (checked 20 Oct 2026)
- ICO: How do we comply with the PECR rules? (checked 20 Oct 2026)
- EDPB: Guidelines 2/2023 on Technical Scope of Art. 5(3) of ePrivacy Directive, version 2.0 (adopted 7 Oct 2024; checked 20 Oct 2026)
- California Privacy Protection Agency: Frequently asked questions (checked 20 Oct 2026)