LinkedIn Conversions API for B2B: conversion rules, li_fat_id and hashed e-mail

What LinkedIn needs from you

1. A conversion rule in Campaign Manager (Analyze → Conversion tracking) with source "Conversions API". Each rule has a numeric id; the API refers to it as urn:lla:llaPartnerConversion:{id}.
2. An OAuth 2.0 token with the r_ads and rw_conversions scopes, issued to a user with access to the ad account. Track connects the account through LinkedIn OAuth and refreshes the token automatically.
3. The Insight Tag in the browser if you want hybrid tracking — it sets the li_fat_id first-party identifier that makes server matching precise.

The request

POST https://api.linkedin.com/rest/conversionEvents with headers Authorization: Bearer <token>, LinkedIn-Version: 202608, X-Restli-Protocol-Version: 2.0.0 and Content-Type: application/json:

{
  "conversion": "urn:lla:llaPartnerConversion:123456",
  "conversionHappenedAt": 1767225600000,
  "conversionValue": { "currencyCode": "EUR", "amount": "1200.00" },
  "eventId": "01J9EXAMPLESOURCEEVENTID00",
  "user": {
    "userIds": [
      { "idType": "SHA256_EMAIL", "idValue": "<sha256>" },
      { "idType": "LINKEDIN_FIRST_PARTY_ADS_TRACKING_UUID", "idValue": "<li_fat_id>" }
    ],
    "userInfo": { "firstName": "…", "lastName": "…", "companyName": "…", "title": "…", "countryCode": "DE" }
  }
}

A 201 Created confirms acceptance. Batch creation uses the same path with the X-RestLi-Method: BATCH_CREATE header and an elements array; LinkedIn answers per element.

Versioning is monthly. The LinkedIn-Version header names a version that stays valid for about a year; Track pins it in its version registry and warns before the sunset date.

Identifiers and what actually matches

• LINKEDIN_FIRST_PARTY_ADS_TRACKING_UUID — the li_fat_id value the Insight Tag stores (also appended to landing page URLs as li_fat_id). Highest match quality; requires marketing consent to capture.
• SHA256_EMAIL — the normalised, lowercase business e-mail, hashed. B2B leads usually supply it; it works without the tag.
• userInfo — plain-text name, company, title, country. LinkedIn uses them as auxiliary matching signals; send only the ones your policy allows.

No conversionValue is required for lead events, but sending a modelled value helps campaign optimisation.

Deduplicating with the Insight Tag

If a rule is tracked by both the Insight Tag (window.lintrk('track', { conversion_id: 123456 })) and the API, pass the same eventId on both paths; LinkedIn deduplicates identical ids for the same rule. In practice most B2B teams keep browser and server rules separate: "Form submit (tag)" fires immediately, "Qualified lead (CRM)" arrives from the server days later with a different rule, so nothing needs deduplicating.

The 90-day window and delayed qualifications

conversionHappenedAt must be within the last 90 days. That is what makes CRM-driven conversions practical: when a lead becomes an opportunity three weeks after the click, upload it with the original conversion time and the e-mail, and LinkedIn attributes it back to the ad interaction.

Errors

The wizard validates the connection by listing the conversion rules the token can see, so an unknown rule id is caught before the first event.