FullContact has spent over a decade building a person-centered identity graph that helps brands understand who their customers are. For companies with fragmented data (emails from one system, loyalty IDs from another, anonymous website sessions from a third), FullContact stitches those fragments into a single, persistent identity for each person, with privacy compliance built in.
To write this FullContact review, we analyzed the platform in detail. We believe it fits if:
You need to unify fragmented consumer identifiers across marketing systems into a single person-level profile
Your business operates exclusively in the United States
You're a MarTech/AdTech platform, publisher, or enterprise brand with first-party data assets
You prioritize privacy-safe identity resolution with no data pooling
You need real-time API responses (under 150ms) for in-session personalization
You want consumer-level enrichment (demographics, interests, household data) rather than B2B company data
However, FullContact might not fit if:
You need B2B prospecting with verified direct dials and business emails at scale
You operate outside the United States or serve a global audience
You want outbound engagement tools, CRM functionality, or campaign execution built in
You need buyer intent signals tied to specific accounts and contacts
You're looking for a self-serve platform with transparent, published pricing
You want conversation intelligence, sales automation, or marketing orchestration in one system
In this case, consider ZoomInfo: an AI GTM Platform that goes well beyond identity resolution. Where FullContact resolves consumer identifiers into unified profiles, ZoomInfo provides the B2B go-to-market stack: 500M contacts with verified direct dials and business emails, buyer intent signals, conversation intelligence, AI-powered prospecting, marketing automation, and multi-channel campaign execution, unified through the GTM Context Graph.
We've included a detailed look at ZoomInfo at the end of this review for teams that need B2B intelligence and execution beyond what identity resolution alone delivers. To explore ZoomInfo directly, start with a free trial here.
What is FullContact?
FullContact is a privacy-safe identity resolution platform founded in 2010 by Bart Lorang in Denver, Colorado.
The company started as a developer-first contact enrichment API, helping CRMs and sales tools fill in customer records from social profiles and public data. Over the following decade, it pivoted from contact management into enterprise identity resolution, a shift that crystallized with the Resolve product launch in 2020.
In Q4 2024, Ziff Davis, Inc. (NASDAQ: ZD) acquired FullContact. FullContact now operates within Ziff Davis's Martech division alongside Campaigner, Moz, SMTP, Kickbox, iContact, and Email Industries.
Today, FullContact sells four products built on its Person-Centered Graph: Acumen (lead identification from anonymous website traffic), Resolve (identity resolution that unifies fragmented customer data), Enrich (appending 900+ data attributes to customer records), and Identity Streme (encrypted first-party data management). The graph maps 248 million U.S. consumer profiles across 50+ billion identifiers, with 200 million daily updates.
FullContact's target buyers are MarTech/AdTech platforms, enterprise brands with offline customer data, and publishers resolving unauthenticated web traffic into addressable audience segments. Named customers include Blackbaud, Precisely, ADP, HubSpot, and Copper.
FullContact Pros & Cons
Pros | Cons |
|---|---|
Person-centered identity graph with 248M U.S. profiles | U.S.-only coverage; no international identity resolution |
Real-time API responses under 150ms | No outbound engagement, CRM, or campaign execution tools |
900+ enrichment attributes across consumer and professional data | No published pricing for Resolve, Enrich, or Identity Streme |
Privacy-safe architecture with no data pooling | Data must be deleted within 30 days of contract termination |
Value-based billing (pay only for successful matches) | Post-acquisition leadership uncertainty (no listed CEO) |
Cookieless visitor recognition without third-party cookies | B2B company data coverage depth not documented |
SOC2 Type II, GDPR, and CCPA compliant | 12-month minimum commitment; no monthly billing option |
FullContact Review: How It Works & Key Features
Acumen Lead Identification: FullContact converts anonymous website visitors into identified leads with professional contact details.
Acumen tackles a specific problem: 98% of unknown website visitors never convert. That traffic disappears without identification, and the acquisition spend that brought those visitors goes with it.
Source: FullContact
The process starts with a JavaScript webtag installed via a tag manager or directly in HTML. When a visitor lands, Acumen matches against the Identity Graph using deterministic identity resolution based on observed data points, not IP-lookup guessing. Each resolved visitor receives a PersonID (a persistent identifier), and the system returns their name, work email, phone number (on Core plan and above), employer, job title, location, and LinkedIn URL.
The typical Acumen customer recognizes 45-70% of website visitors, and average customers identify 100+ leads with professional email addresses within the first week. With behavioral tracking enabled, Acumen also captures visited URLs, page sequences, and time-on-site data to flag high-intent signals like repeated visits and extended browsing.
Source: FullContact
Integrations include Google Tag Manager, Google Analytics, Segment, Tealium, Adobe Experience Platform, WordPress, Webflow, and native Slack notifications for real-time lead alerts.
Resolve Identity Resolution: FullContact unifies fragmented customer identifiers into a single persistent profile.
Resolve is FullContact's core product. It takes fragmented identity data (different email addresses, phone numbers, device IDs, loyalty accounts, and social profiles scattered across systems) and links them to a single PersonID that persists across devices, channels, and platforms.
Source: FullContact
The process follows three stages: Identify, Resolve, and Enrich. You submit whatever identity fragments you have (emails in cleartext, MD5, or SHA-256; phone numbers; postal addresses; social profile URLs; Mobile Ad IDs; internal customer IDs) through a Multi Field Request accepting up to 25 identifiers per type.
Source: FullContact
The Identity Graph matches these against its records and assigns a persistent PersonID. From there, profiles can be enriched with 900+ personal and professional insights.
FullContact reports an average match rate of 93% with expected deduplication of 10-15% of duplicate records. The matching uses machine learning confidence scores with a "Belief Vector" that weighs positive and negative evidence, and buyers can tune confidence levels per request to balance precision against match rate. A Human in the Loop process handles edge cases where automated matching falls short.
Source: FullContact
Customers access the identity graph without giving any of their data away. There's no data pooling or co-op requirement. FullContact backs this with a 3X recognition and reach guarantee (limited to U.S.-based individuals).
Source: FullContact
Enrich Data Enrichment: FullContact appends 900+ consumer and professional attributes to existing records.
Enrich transforms a single identifier into a detailed customer profile. The system draws from 248 million U.S. consumer profiles, rebuilt biweekly from thousands of data sources with 200 million daily updates.
Source: FullContact
Data is organized into modular Person Insights Bundles that customers enable per account:
Individual (age, gender, city, country, birthday, name, education, Twitter URL)
Individual Plus (all of the above plus 330 data elements: behavioral insights, social media, marital status, net worth, household, income, investments, pets)
Core Segmentation (dwelling type, homeownership, marital status, income, net worth, language, children)
Interests (consumer affinities across automotive, brands, dating, fashion, gaming, health, entertainment, sports, streaming)
Professional (current job title, organization, business email, business phone, address)
Employment History (current and past organizations, titles, start/end dates)
Email Signals (cross-network engagement metrics: first/last open, click, reply, unsubscribe, bounce)
Email Risk (hard bounce, spam trap, disposable, bot, and abuse flags with composite risk score)
Market Verticals (industry segments including Automotive, CPG, Financial Services, Media, Retail, Tech, Travel)
Source: FullContact
A separate Company Enrich endpoint returns company data (name, location, founding year, employee count, SIC and NAICS codes, web traffic rank) from a domain input. Real-time API responses arrive in 40ms with 99.99% uptime, and batch processing handles hundreds of millions of records within a day.
The breadth here leans consumer. Where B2B-focused platforms emphasize company data depth and verified business contacts at scale, Enrich is built around a whole-person view combining personal attributes (household composition, interests, financial indicators) with professional data.
Identity Streme: FullContact provides encrypted first-party data management without PII exposure.
Identity Streme is FullContact's most recent core product (launched April 2023). It handles PII so customers don't have to.
Source: FullContact
The flow works in three stages. First, the brand sends siloed datasets via API or batch upload, and everything is ingested, encrypted, and obfuscated upon receipt. PII is deleted upon receipt. Second, incoming fragments are matched against the Identity Graph to produce a persistent PersonID. Third, brands use those PersonIDs downstream for segmentation, personalization, and ad targeting, and can share data with second-party partners without exposing raw PII.
FullContact positions Identity Streme as "like a data clean room...but better", citing per-brand encryption as the differentiator. The core guarantee: your data is never commingled or combined with other data, including FullContact's.
Key capabilities include identity.map for mapping internal IDs (customerID, loyaltyID, CDPID) to PersonIDs, identity.delete for right-to-erasure compliance, Customer Tags for storing segments as key-value pairs, and Secure Sharing for sharing identities with partners using persistent Partner IDs. Client libraries are available in Go, Java 8, Java 11+, and Python.
Pricing: Acumen has published tiers; all other products require sales contact.
FullContact's pricing splits into two worlds. Acumen is the only product with public pricing, billed monthly on a 12-month subscription:
Essentials: $99/month
Professional email addresses, LinkedIn profile matching
3 platform user seats, single domain
Core: $300/month
Phone numbers included, unlimited hashed emails for advertising
Plus: Contact sales
Custom lead volumes, priority support, SOC2 Type 2 reports, unlimited domains
Source: FullContact
Resolve, Enrich, and Identity Streme require direct sales contact with no published pricing. A free API key with 1,000 matches is available for developers, and Acumen offers a 14-day free trial with no credit card required.
FullContact uses match-based pricing: you pay only when the API returns data (a "200 Response"). Queries returning no match cost nothing. Contracts auto-renew unless 30 days written notice is provided, and payment obligations are non-cancelable with fees non-refundable.
One contractual detail worth noting: customers can retain and use FullContact data only while they remain active paid customers, and all FullContact data must be deleted within 30 days of termination.
Where FullContact Falls Short
FullContact works well for its intended purpose, but several limits appear depending on what your team needs. These reflect the boundaries of a platform built as identity infrastructure rather than a go-to-market system.
U.S. Only. FullContact's 3X recognition and reach guarantee applies only to U.S.-based people. The FAQ states FullContact does not do business with companies looking for identity resolution outside of the United States. For any organization with international customers or audiences, this is a hard ceiling.
Source: FullContact
No Activation Layer. FullContact resolves and enriches data but does not help you act on it. There's no campaign execution, email sequencing, sales automation, conversation intelligence, or native CRM. It provides no lists or audiences for marketing purposes and will not provide PII that the organization doesn't already have. Customers must activate resolved data through separate platforms, adding integration work and cost.
B2B Depth is Not Documented. While Enrich includes professional profiles and company enrichment, the site does not specify B2B company data coverage or company identity graph scale.
The platform leans toward B2C consumer identity. Teams needing verified B2B contact data at scale (direct dials, business emails, org charts, technographics, buyer intent) will find the coverage thin for outbound sales.
Pricing Opacity. Only Acumen has published prices. Resolve, Enrich, and Identity Streme all require contacting sales, with no pricing calculator or self-serve tier. For mid-market buyers benchmarking options, this slows evaluation.
Post-Acquisition Uncertainty. Since the Ziff Davis acquisition in Q4 2024, FullContact's team page lists no CEO or President, only directors and VPs. The last major product announcements were Identity Streme (April 2023) and the Snowflake Native App (June 2023), with a gap in product news between mid-2023 and early 2026. Enterprise buyers evaluating long-term commitment should probe the roadmap directly.
Data Deletion on Termination. When a contract ends, all FullContact data must be deleted within 30 days. For organizations building durable data assets, this dependency on an ongoing subscription creates lock-in worth factoring into total cost of ownership.
These limits aren't failures. They follow from building a specialized identity resolution layer rather than a go-to-market platform. But for teams that need B2B prospecting, buyer intent signals, outbound execution, and deal intelligence alongside their data, the gap is real.
Top FullContact Alternative for B2B Go-to-Market: ZoomInfo
ZoomInfo is an AI GTM Platform built on a large B2B data foundation: 500M contacts, 100M companies, and 135M+ verified phone numbers, plus 200M+ verified business emails.
FullContact resolves consumer identities; ZoomInfo handles B2B intelligence and execution, from data discovery through campaign execution and deal management.
That data feeds the GTM Context Graph, which fuses ZoomInfo's B2B data with your CRM records, conversation transcripts, and behavioral signals, processing 1.5B+ data points daily. The result: AI that understands not just what happened in a deal, but why, and what to do next.
Source: ZoomInfo
Teams access this through three paths: GTM Workspace for sellers, GTM Studio for marketers and RevOps, or APIs and MCP for custom tools or AI agents.
Source: ZoomInfo
Comprehensive B2B Data: ZoomInfo's B2B dataset covers contacts, companies, and intent signals, verified at scale.
ZoomInfo's data covers three dimensions: identity data (who buyers are and how to reach them), company context (firmographics, technographics, org charts), and signals (buyer intent and behavioral data showing when a company is actively in-market).
The numbers: 500M contacts, 100M companies, 135M+ verified phone numbers, 120M direct-dial phone numbers, and 200M+ verified business email addresses. Global coverage extends to 34M+ company profiles outside North America, 200M+ professional profiles outside NA, and 45M+ mobile numbers outside NA.
Source: ZoomInfo
In 2025 alone, ZoomInfo added 10.2 million contacts through enhanced title classification and expanded international mobile coverage by 1.8 million numbers across six European markets.
This data is verified through a multi-source pipeline backed by 300+ human researchers and up to 95% accuracy on first-party data. In a Fortune 500 competitive RFP analyzing 25 million contacts across vendors, the independent consultant concluded that "no other competitor came even close."
Beyond contact data, ZoomInfo provides Buyer Intent signals tracking 210 million IP-to-Organization pairings and 6 trillion+ new keyword-to-device pairings monthly, technographic profiles for 30+ million companies, and WebSights for resolving anonymous website traffic to companies and contacts.
Source: ZoomInfo
AI-Powered Execution: ZoomInfo translates data into action through GTM Workspace and GTM Studio.
Where FullContact stops at resolving and enriching data, ZoomInfo carries through to execution.
GTM Workspace gives sellers a single view where prioritized accounts, AI-drafted outreach, deal intelligence, and CRM updates converge. Built on Anthropic's Claude, the AI agents inside Workspace research accounts, generate follow-ups, monitor signals, and surface next actions.
Source: ZoomInfo
Customer results: Seismic's sales team boosted productivity by 54% and saved 11.5 hours per week; Thomson Reuters increased closed-won deals by 40%.
Source: ZoomInfo
GTM Studio gives marketers and RevOps a builder environment where audience definition, multi-channel campaign orchestration, and pipeline measurement happen in natural language. Expansion plays that used to take 3 weeks now launch in 30 minutes, without engineering support.
For teams building their own tools, API access is included in all relevant plans, and the MCP server connects AI models directly to ZoomInfo's data (currently supporting Claude and ChatGPT).
Source: ZoomInfo
Conversation Intelligence and Deal Context: ZoomInfo captures why deals move, not just that they moved.
Chorus, ZoomInfo's conversation intelligence product, captures and analyzes customer calls, meetings, and emails. This goes beyond transcription.
Source: ZoomInfo
Chorus extracts the context behind interactions: why a deal accelerated (executive sponsorship secured), why a champion went quiet (internal budget battle), and what a competitive mention predicts about deal risk.
That context feeds into the GTM Context Graph, which connects conversation signals with CRM data, intent signals, and ZoomInfo's third-party intelligence. The difference: AI that doesn't just know the CFO joined the last call, but recognizes that executive sponsorship entering at this stage, combined with specific questions asked, matches the pattern behind closed-won deals in your segment.
Pricing and Access: ZoomInfo offers both free and paid entry points with multiple product tiers.
ZoomInfo uses a custom-quoted, seat-and-credit-based subscription model. Like FullContact's core products, exact pricing requires a conversation with sales. But ZoomInfo provides more entry points.
ZoomInfo Lite is a permanent free tier (no trial, no time limit) that includes access to ZoomInfo's B2B database, 10 monthly export credits, WebSights Lite (up to 10 website visitor reveals per day), the ReachOut Chrome Extension, built-in email sending, and HubSpot integration. A separate 7-day free trial provides broader access to core features.
Source: ZoomInfo
Paid plans are organized into Sales (Professional, Advanced, Enterprise), Marketing (Marketing Demand, ABM Lite, ABM Enterprise), and standalone products (Chorus, Chat).
Each tier adds capabilities: Professional covers core data and prospecting; Advanced adds buyer intent signals, Account Fit Scores, and automated workflows; Enterprise adds real-time intent, AI-generated account summaries, custom integrations, and dedicated support.
FullContact or ZoomInfo: Comparison Summary
FullContact | ZoomInfo | |
|---|---|---|
Primary focus | Consumer identity resolution and data enrichment | AI GTM Platform |
Target buyers | MarTech/AdTech platforms, publishers, brands | Sales, marketing, RevOps, and GTM engineering teams |
Data coverage | 248M U.S. consumer profiles, 50B+ identifiers | 500M contacts, 100M companies, 200M+ business emails, 135M+ verified phones |
Geographic scope | U.S. only | Global (34M+ company profiles, 200M+ professional profiles outside NA) |
Enrichment depth | 900+ consumer attributes (demographics, interests, household) | 300+ company attributes (firmographics, technographics, org charts) |
Buyer intent signals | No | Yes (210M IP-to-Org pairings, 6T+ keyword pairings monthly) |
Outbound execution | No (infrastructure only; no engagement tools) | Yes (AI-drafted outreach, multi-channel sequences, sales automation) |
Conversation intelligence | No | Yes (Chorus: call recording, AI analysis, deal intelligence) |
Website visitor ID | Yes (person-level via Acumen, 45-70% match rate) | Yes (company and contact-level via WebSights) |
CRM integration | Via Zapier and partner platforms | Native Salesforce, HubSpot, Dynamics 365 + 120 marketplace integrations |
Privacy architecture | SOC2 Type II, no data pooling, consumer privacy portal | ISO 27001, ISO 27701, SOC 2 Type II, TRUSTe GDPR/CCPA |
Free tier | 1,000-match API key (one-time); 14-day Acumen trial | ZoomInfo Lite (permanent, no time limit) + 7-day trial |
Published pricing | Acumen only ($99-$300/mo); others require sales | No published prices; custom-quoted |
Best for | Unifying fragmented consumer identifiers for U.S. B2C use cases | B2B prospecting, deal intelligence, and GTM execution at scale |
Final Verdict
The choice between FullContact and ZoomInfo depends on whether you need identity infrastructure or a go-to-market system.
Choose FullContact if your primary need is resolving fragmented consumer identifiers into unified profiles for U.S.-based audiences. It's built for MarTech and AdTech platforms embedding identity resolution into their own products, publishers monetizing unauthenticated traffic, and enterprise brands connecting offline customer data (loyalty programs, POS, print subscribers) to digital channels. The privacy-safe architecture, real-time API performance, and consumer-level enrichment depth (900+ attributes spanning household, interests, and financial data) suit organizations that already have their activation tools and need a specialized identity layer underneath.
Choose ZoomInfo if you need B2B intelligence and execution in one platform. ZoomInfo covers the full go-to-market workflow: finding the right accounts and contacts with verified direct dials and business emails, identifying which are actively in-market through buyer intent signals, understanding deal context through conversation intelligence, and executing outreach through AI-powered tools in GTM Workspace and GTM Studio. With global coverage, a permanent free tier, and API/MCP access for custom builds, ZoomInfo serves as both the data foundation and the execution engine for revenue teams.
Get started with ZoomInfo here.
FullContact and ZoomInfo occupy different positions in the data landscape. FullContact specializes in consumer identity resolution. ZoomInfo is a B2B platform that turns data into pipeline. Your choice depends on whether you need to resolve who your customers are, or find, engage, and close new ones.
