ID Resolution

ID Resolution (Identity Resolution) is the process of recognizing that multiple identifiers — collected across different sessions, devices, browsers, or platforms — belong to the same person, and merging them into a single unified customer profile.

CustomerLabs performs ID resolution by collecting External IDs, applying identity matching algorithms, and building a continuous 360-degree profile for each user.

The Problem: Fragmented User Identity

A single customer interacts with a business across many contexts:

• Visits the website on a desktop browser anonymously
• Returns on a mobile device and browses product pages
• Clicks an ad, lands on the site, and adds items to cart
• Submits a lead form providing their email
• Purchases a week later after receiving a retargeting email

Without ID resolution, each of these interactions is recorded as a separate, disconnected user. The result is:

• Duplicate or conflicting user profiles across data sources
• Incomplete attribution — the ad click that drove the purchase is never connected to the conversion
• Inaccurate audience segments built on fragmented data
• Poor ad platform signal quality due to inconsistent user identities

Note

The more touchpoints a user has across devices and channels, the larger the identity gap becomes without resolution. ID resolution is what turns disconnected events into a coherent customer journey.

How CustomerLabs Resolves Identity

CustomerLabs uses two matching strategies to resolve user identity: deterministic identifiers provided directly, and external identifiers assigned by other platforms.

Deterministic Matching

Deterministic matching links profiles using exact, known identifiers — such as email address, phone number, or a CustomerLabs user ID. When a user provides their email on a lead form and later logs in on a different device, CustomerLabs detects the shared identifier and merges the profiles.

This is the strongest form of identity resolution — no inference, no ambiguity.

Platform-Assigned External IDs

In addition to identifiers provided directly by the user, CustomerLabs also collects and stores external IDs assigned by other platforms — such as shopify_cart_token, facebook__fbp, or a CRM’s internal user ID. These are captured as External IDs and attached to the user’s profile.

When an event arrives without a deterministic identifier (e.g., an anonymous user returns after clearing cookies), CustomerLabs looks up the profile using any matching External ID — such as a shopify_cart_token that was captured in an earlier session — and links the new event to the existing profile.

This allows CustomerLabs to extend identity resolution beyond explicit identifiers without relying on browser-based inference.

The Resolution Pipeline

1. Data Ingestion — Events and identifiers are collected from all sources: website, app, CRM, offline files, and ad platforms
2. Identity Graph Matching — CustomerLabs compares incoming identifiers against the existing identity graph, detecting overlaps and shared keys across profiles
3. Profile Stitching — Matched fragments are merged into a single unified profile, combining all known traits, events, and External IDs
4. Real-Time Updates — The unified profile is updated in real time as new events and identifiers arrive
5. Privacy & Compliance — PII is masked in the platform; data sent to destinations is hashed using SHA256; PHI is scrubbed for restricted industries

What Gets Stitched

CustomerLabs merges all available identifiers into the user’s unified profile:

Identifier Type	Examples
User Traits	Email, phone number, name, address
External IDs	customerlabs_user_id, facebook__fbp, google_analytics__client_id, shopify_cart_token, CRM IDs
Click IDs	fbclid (Facebook), gclid (Google), ttclid (TikTok)
Session identifiers	Browser cookies, device IDs
Offline identifiers	Lead IDs from form submissions, offline conversion data

Once stitched, all these identifiers are stored together in the user’s 360-degree profile and travel with that profile across all downstream activations.

Cookieless Identity Resolution

A key challenge in modern tracking is cookie loss. Safari’s Intelligent Tracking Prevention (ITP) deletes first-party cookies after 24 hours. Privacy browsers and ad blockers restrict them further.

CustomerLabs addresses this by storing resolved identities server-side — not in browser cookies. When a user’s cookies are cleared and they return to the site, CustomerLabs can re-identify them using any surviving identifier (such as an email captured in a future form submission or a customerlabs_user_id attached server-side) and re-attach their full profile history.

Note

This server-side persistence means click IDs like _fbp or gclid captured at the start of a user’s journey remain part of their profile — even weeks later when a purchase event fires — enabling accurate attribution regardless of browser cookie state.

What ID Resolution Enables

Full-Funnel Tracking

CustomerLabs connects every touchpoint — from the first anonymous page view to a repeat purchase — into a single user timeline. This allows accurate attribution across the entire funnel, not just the last known session.

Accurate Attribution

When offline conversions, lead IDs, and click IDs are all stitched to the same profile, attribution models have a complete picture. Ad platforms receive consistent identifiers across all events, improving match accuracy.

Improved Event Match Quality (EMQ)

Sending platform-native identifiers (like facebook__fbp) alongside hashed user traits in every event increases Meta’s ability to match that event to a user in its system. Higher EMQ leads to better audience targeting and lower CPAs.

Offline Conversion Merging

Lead IDs from form submissions and gclid from Google ad clicks can be unified in the same profile. When those leads convert offline, the conversion can be attributed back to the original ad interaction through the stitched identity.

Lifetime Value Tracking Across Channels

Because all interactions across devices, channels, and time are connected under one profile, businesses can accurately calculate customer lifetime value and segment users by long-term behavior — not just their most recent session.

Richer Audience Segments

Unified profiles built through CustomerLabs’ ID resolution have more complete data than any single source alone. Audience segments built on these unified profiles are more accurate, reducing wasted spend on misclassified users.

Tip

For more on how External IDs power the stitching process, see the External IDs documentation.