GET api/templates, 500 server error when fetching all templates

​@Sujan first off do you actually have templates created after 2025-12-11.  Have you tried greater-than for a date before that?

For what it’s worth, I do a call to GET /api/templates?filter=created(greater-than,”2025-12-12”), I.e. today’s date, and even though I have no templates created greater than this date the API responds with an empty list ([]) as expected. In the case where I try to pass a future date (2025-12-13), the API returns a 400 error as expected too. 

I’m thinking ​@Sujan’s theory is correct that there is a problematic template causing problems here. 
​@Sujan, do you have access to the account you’re making the API requests in? You could try to call GET Template on all templates created on or after 2025-12-11 to find the bad apple, remove it, and your problem should be solved.

If you don’t have access, then I think the only way for this to get resolved is through the Klaviyo team investigating and patching the root cause of the 500.  cc ​@Byrne C 

Cadence / Book a demo

Hi ​@Sujan,

Thanks for reaching out about the error! I want to confirm what you and ​@cadence mentioned, that there may be a problematic template that’s causing this. That being said, in some situations, 500 server errors need to be investigated and patched on our end. It might be a good idea to reach out to us at Klaviyo.com/support, so we can take a look and determine the cause of this error, and if action is needed on our end.