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Migration FAQ: v1/v2 API retirement

Find answers to common migration questions for the legacy API retirement.


v1/v2 legacy APIs are scheduled to retire on June 30, 2024.

Users of Klaviyo's v1/v2 APIs have until June 30, 2024 to migrate to our new APIs. At this time, our v1/v2 APIs will officially be retired. To learn more about Klaviyo’s API lifecycle, check out our updated API versioning and deprecation policy.

What if I cannot meet the deprecation deadline?

API calls made to v1/v2 endpoints after June 30, 2024 fail automatically, and no data from the request is sent to Klaviyo. Any marketing automations reliant on v1/v2 API calls (segments, lists, flows, campaigns, reports, etc.) will no longer update.

What response can I expect if I call a v1/v2 API endpoint on July 1, 2024?

v1/v2 API calls made on July 1, 2024 will return a 410 GONE error code. The call’s response body contains a link to the correct new API equivalent. For more information on which new endpoints to use, check out the API comparison chart.

What will users of my integration experience if I am not able to complete the migration by the deadline?

Any remaining instances of v1/v2 APIs in your integration may cause parts or all of your integration to break.


If a 3rd party integration you're using fails to migrate to Klaviyo's new APIs prior to June 30, 2024, the integration is at risk and may no longer function properly. Any activities dependent on data coming from that integration will cease receiving new information. If your account is impacted by the deprecation, we recommend reaching out directly to the company who built the integration. This is the best course of action to get the integration up and running again. We are hard at work collaborating with our ecosystem to help them through the migration process, however, it is the responsibility of the integration owners to ensure compliance with the migration deadline.

Can you provide a list of accounts using my integration?

We are not able to provide this information.

How do I find what APIs are being called by my integration?

If you have a Klaviyo demo or staging account, you can go to the Developer tools dashboard, and click the Audit API Endpoints section to download an audit of all v1/v2 API usage. Check out this guide to read more about using the API audit tool. If you do not have a demo or staging Klaviyo account, you will need to search your integration’s codebase to identify calls.

Can you confirm that I have migrated all my API calls?

The best way to ensure you have fully migrated your API calls is to confirm your integration codebase does not include any calls to our v1/v2 APIs. If you are still unsure that your migration is complete, contact your partner manager.

How do I start the migration process?

We recommend reviewing the migration strategy documentation to begin the migration process.

Where can I see what new endpoints to use as I migrate?

To compare legacy APIs to their new API equivalents, please review the API comparison chart.

My integration only uses Track and Identify, how can I migrate?

The Track and Identify migration guide offers specific guidance for integrations using only these two legacy APIs.

Where can I go if I need additional help?