We’ve made an update to how invalid phone numbers are handled in Subscribe, Create Profile and Create Event APIs that makes it easier to successfully add profiles and log events when multiple identifiers are provided.

What changed

If a request includes a valid identifier (such as email address) but an invalid phone number, the API will now:

• Process the request based on the email.
• Ignore the invalid phone number (instead of returning a 400).
• Return a header indicating partial failure within API Logs

  X-Klaviyo-Partial-Failure: phone_number 

   

If the request only includes a phone number and the phone number is invalid, the request will still fail with a 400.

Why this matters

This change reduces data loss and ensures that valid subscribers and events are not blocked by phone number formatting issues.