What is identity resolution?
Identity resolution is the work of deciding which records belong to the same person.
A customer arrives on a phone and again on a laptop. They buy once as a guest and once signed in. They sit in an email list under an address they stopped using two years ago. Identity resolution is what recognises those as one customer rather than five.
The core definition is stable. The ambiguity is in the product category behind it, because two quite different kinds of software are sold under the phrase — and they solve opposite-facing problems.
The short version. One kind works inward, attempting to associate some of the anonymous traffic on your site with a contactable identity. The other works outward, matching the customers you already know to identities on outside platforms. Knowing which gap you have settles the shortlist before you look at a single vendor.
There is also a third identity problem that buyers fold into the same phrase: duplicate or conflicting customer records inside their own stack. That is a customer-data problem rather than either of the two markets below, and it is worth ruling out first.
What do buyers mean when they shop for identity resolution?
In these interviews, two purchasing categories dominate the phrase — and asking buyers the same question returns both.
Visitor identification
Attempts to identify a portion of the anonymous traffic already on your site and associate it with a contactable identity, often an email address — reaching people who never filled anything in.
Data onboarding
Matches the customer file you already hold to identities on advertising, media and partner platforms, so the same people can be targeted or measured somewhere else.
The two groups of buyers barely intersect. Across these interviews, the companies evaluating visitor-identification tools are small and the companies evaluating onboarding platforms are large, with almost no buyer appearing in both.
The buyers say it themselves, in answer to the same question. A media company running programmatic advertising across marketplaces describes its onboarding platform as our primary solution for sending audiences to third-party platforms, and says what it values is substantial scale. A small apparel brand answers the same question with a different product entirely: their tool helps de-anonymize site visitors and unify profiles.
They are using the same phrase for different markets.
How the two differ in practice
The mechanisms are different, and so is what goes wrong.
Some inward tools rely on shared identity pools. One buyer describes the category as highly substitutable for that reason: their tool does not offer anything unique compared to other anonymous ID resolution tools, which all rely on the same database. Outward tools match first-party records against large identity graphs or platform-linked identifiers, which is why coverage can vary by provider and by region.
Some inward tools use publisher or identity networks to make a matched contact actionable. A specialty retailer describes theirs using a publisher network to activate emails when customers visit our site — and reports deliverability problems as a direct result. Outward tools typically deliver the matched audience into advertising, media or partner platforms, where the activation happens.
Cost appears on both sides, for different reasons. Pricing is the leading complaint theme for the most-rated onboarding platform in our corpus: one buyer describes a model that requires payment every time we use their service, and calls the cost and the modelling opaque. On the inward side the cost complaint is about substitutability rather than scale.
Compliance and clarity appear as evaluation concerns on the inward side. The retailer above is weighing a competitor that might be a better long-term fit due to compliance and clarity issues. On the outward side, privacy and compliance appear in positive buyer comments about the leading platform.
What do buyers rate the tools?
Ratings on both sides are mixed. The complaints surfaced here focus more on pricing, clarity, deliverability and substitutability than on an outright failure to produce matches.
| Product | Rating | What it means here |
|---|---|---|
| LiveRamp | 7.5 | The most-rated identity platform in our corpus by a wide margin, and the clearest recurring enterprise example of data onboarding here. Pricing is its leading complaint theme. |
| Acxiom | around 7.5 | Rated by too few buyers for a decimal, but sits a little above LiveRamp on a much smaller sample. |
| Amperity | 7.2 | A CDP doing the identity job rather than a pure onboarding vendor — which is why the categories blur. |
| Zeta | 6.6 | Sits across identity, data and marketing execution, so buyers rate it on more than the match. |
| Epsilon | 6.3 | The lowest-rated of the well-sampled onboarding names here. |
| Neustar | not rated | Too few buyers rated it to publish a number, though it is still named in enterprise identity conversations. |
| Product | Rating | What it means here |
|---|---|---|
| Retention.com | 7.7 | The highest-rated visitor-identification tool here, on a solid if not large sample. |
| Opensend | around 7 | Too few buyers for a decimal. The tool in both buyer accounts on this page — adequate at the job, and the one a buyer called substitutable. |
| Black Crow | around 7 | Rated by too few buyers for a decimal; appears in the same smaller-ecommerce stacks. |
| Wunderkind | 6.4 | The most-rated tool in this group and the lowest-rated. It spans identity and messaging, so buyers are scoring more than the identification itself. |
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Ask where the identity gap actually is.
People browse and leave without ever identifying themselves, and your list is growing slower than your traffic. That is the inward problem, and the tools that solve it are the ones smaller ecommerce teams in these interviews are buying.
You know who your customers are, but you cannot reliably reach or measure them on advertising and media platforms. That is the outward problem, and it is the one that shows up beside programmatic advertising, clean rooms and media measurement.
Your records disagree with each other before either of the above becomes relevant — duplicate profiles, an unreliable customer view across systems. That is neither of the two purchasing categories above; it is an internal identity-resolution problem, typically handled in a customer data platform, identity graph or customer-data layer.
The third case is worth checking first, because it calls for a different class of solution altogether. And whichever applies, the evaluation questions are well covered by buyers who have already done it: what identity-resolution buyers wish they had known goes into match rates, deterministic versus probabilistic matching, and what the pricing actually meters. If the outward case is yours and the data cannot leave either side, a data clean room is the adjacent structure to understand.
Common questions
What is identity resolution?
Identity resolution is the work of deciding which records belong to the same person. A customer arrives on a phone and a laptop, buys once as a guest and once signed in, and appears in an email list under an old address. Identity resolution is what recognises those as one customer rather than five. The core definition is stable. What is not stable is the product category behind it: buyers use the phrase for multiple jobs, with two purchasing categories recurring particularly clearly — visitor identification and data onboarding — and which one a buyer means tracks closely with the size of the company they work for.
What do buyers mean when they shop for identity resolution?
Visitor identification works inward. It takes the anonymous traffic already on your site and resolves some of it to a contactable person, usually an email address, so you can market to people who never filled in a form. Data onboarding works outward. It takes the customer file you already have and matches it to profiles on advertising, media and partner platforms so you can target or measure the same people somewhere else. One attempts to turn some anonymous site visitors into contactable identities. The other turns existing customer records into an addressable audience on someone else's platform. They are not substitutes, and in these interviews almost no buyer is shopping for both.
What is visitor identification and how does it work?
It attempts to associate some anonymous site traffic with a contactable identity, typically an email address, and in these interviews it is bought almost entirely by smaller ecommerce teams. Buyers describe the mechanism plainly: one says the tool helps de-anonymize site visitors and unify profiles, and another describes their tool using a publisher network to activate emails when customers visit the site. That mechanism is also where the complaints come from — the same buyer reports deliverability problems, and is weighing a competitor they think is a better long-term fit on compliance grounds.
What is data onboarding?
Data onboarding matches your first-party customer file to identities on outside platforms so the same people can be targeted or measured there. One buyer describes their onboarding platform as their primary solution for sending audiences to third-party platforms, and the thing they value about it is scale — the ability to integrate audience data across many platforms at once. In these interviews it is the identity-resolution category bought by large enterprises, and the one that shows up alongside programmatic advertising, clean rooms and media measurement.
What is the difference between identity resolution and data onboarding?
Identity resolution is the broader job of deciding which identifiers and records belong to the same person. Data onboarding is one application of that job: matching a company's first-party customer file to identities on advertising, media or partner platforms so those customers can be targeted or measured there. Visitor identification is another application, focused on associating some anonymous site traffic with contactable identities. So onboarding is a use of identity resolution rather than a synonym for it.
Is visitor identification the same as identity resolution?
No. Visitor identification is one identity use case, not the whole category. It focuses specifically on identifying some anonymous site visitors so they can be contacted. Identity resolution more broadly includes reconciling known customer records inside a first-party stack and matching known customer files to outside identity graphs.
Which kind of identity resolution do you need?
Ask where the identity gap actually is. If the gap is that people browse your site and leave without ever identifying themselves, that is visitor identification. If the gap is that you know who your customers are but cannot reach or measure them on advertising and media platforms, that is data onboarding. The split in these interviews is close to clean: the buyers evaluating visitor-identification tools are small companies, and the buyers evaluating onboarding platforms are large ones. Almost no buyer appears in both groups.
What do buyers complain about with identity resolution tools?
Commercial concerns appear on both sides, but differently. On the enterprise side, pricing is the leading complaint theme for the most-rated onboarding platform in our corpus — buyers describe a model that charges on every use, and call it opaque as well as expensive. On the visitor-identification side the complaint is closer to substitutability and value: one buyer rates their tool adequate but says it offers nothing unique against other tools that all draw on the same underlying database, and is looking to replicate it more cheaply. Deliverability and compliance surface there too, in one buyer's account.
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