LinkedIn Conversions API

Offline and web conversions attributed to LinkedIn ads by hashed email or the first-party li_fat_id tracking identifier.

Verified against the Microsoft Learn documentation on 2026-09-03: Conversions API, API versioning.

Prerequisites

• A LinkedIn Campaign Manager ad account.
• A conversion rule of type "Conversions API" created in Campaign Manager and associated with the campaigns that should get credit.
• A LinkedIn developer app with the rw_conversions and r_ads scopes, and an ad-account role other than Viewer for the authorising member.

What to collect

The version deserves attention: LinkedIn supports each moniker for at least a year and then rejects it outright. A destination that starts failing with a version error needs this field bumped, not a redeploy.

What SaaS Pro Max sends

POST https://api.linkedin.com/rest/conversionEvents
Authorization: Bearer <access token>
Content-Type: application/json
Linkedin-Version: 202608
X-Restli-Protocol-Version: 2.0.0

{
  "conversion": "urn:lla:llaPartnerConversion:1234567",
  "conversionHappenedAt": 1786998896000,
  "conversionValue": { "currencyCode": "USD", "amount": "49.00" },
  "eventId": "<the SaaS Pro Max event id>",
  "user": {
    "userIds": [
      { "idType": "SHA256_EMAIL", "idValue": "<sha256>" },
      { "idType": "LINKEDIN_FIRST_PARTY_ADS_TRACKING_UUID", "idValue": "<li_fat_id>" }
    ],
    "userInfo": {
      "firstName": "Jane", "lastName": "Doe",
      "companyName": "Acme", "title": "Head of Growth", "countryCode": "US"
    }
  }
}

Notes that matter:

• The header is spelled Linkedin-Version in LinkedIn's own documentation (lowercase k), alongside X-Restli-Protocol-Version. HTTP header names are case-insensitive, but matching the docs keeps support conversations short.
• conversionHappenedAt is milliseconds since the epoch, not seconds.
• conversionValue.amount is a decimal string, not a number.
• The email is lowercased with whitespace removed, then SHA-256, hex encoded. LinkedIn does not fold Gmail dots or plus-addressing — Google Ads does, so the two adapters produce different hashes of the same Gmail address.
• userIds is always present, even when empty, because LinkedIn answers 422 ERROR :: /user/userIds :: field is required but not found otherwise. SaaS Pro Max declines to send a conversion with no identifier at all: LinkedIn would accept it and attribute nothing.
• firstName and lastName are only sent together, as LinkedIn requires.
• The li_fat_id comes from the first-party tracking parameter the browser SDK captures on the landing page.

Mapping

The "Conversion rule" column takes either the numeric conversion rule ID or a full urn:lla:llaPartnerConversion:… URN. A rule with neither, and no default configured, is an error rather than a guess.

Different SPM events usually map to different conversion rules — that is how LinkedIn distinguishes a lead from a purchase.

Verifying

1. Press Send test event.
2. A successful create answers 201 Created with no body; the delivery log shows sent.
3. In Campaign Manager → Analyze → Conversion tracking, open the rule. Recent conversions appear there, though attribution can lag by several hours.

Common rejections:

• 401 EMPTY_ACCESS_TOKEN — the token expired (member tokens last 60 days).
• 403 USER_NOT_AUTHORIZED — the authorising member has only the Viewer role.
• 422 on /conversionHappenedAt — the timestamp is outside the accepted window, or was sent in seconds.

Limitations

• A conversion must have happened within the last 90 days. SaaS Pro Max does not even attempt an older one; it records the delivery as skipped.
• One conversion per request. LinkedIn's batch endpoint accepts 5,000, but a batch fails atomically — one bad row rejects the whole payload — which is a poor trade for a stream of independent conversions.
• Rate limits are 600 requests per minute and 500,000 per day per token. Throttling is retried; a rejected payload is not.