String field validation


If I get back a code:300 “Validation Failed.”, it gives back the field name, but not the reason of failure (“max length is XX”).

I found this: Is there a size limit for the agenda field?
What’s the limit for first_name and last_name strings?

I couldn’t find any documentation of your field validation. That’s missing?

[ERROR CODE # 400]: {“code”:300,“message”:“Validation Failed.”,“errors”:[{“field”:“last_name”,“message”:“Invalid field.”}]}

How can I debug this without knowing the max string length of last_name (for example).


The API documents list the validations for each property.

If you expand the Request Body block and click on the user_info object you see all the available properties. You can then click on the properties that say “* validation” to see what they are.

Thanks for your reply. The docs provide the data type, not the validation rules!
it just says: “string”. not max-length rule, for example.

Did you click on the property? They’ll appear when you click on them. Look at the top-right corner of each property in the image:

See here:

Is a first_name string always 64 characters max-length (as in the screenshot you sent), across the Zoom API ? (webinar, meeting registrants, etc…)

I’m not sure if it’s consistent, but it does look like the Meeting Registrants endpoint also has a maxlength of 64. The First Name and Last Name text boxes on an actual registration page match up with that.

Thanks a lot for your quick and helpful replies.

@samly thank you so much for your help - we’ll make sure to reflect these consistently across the docs

Can I get a max length verification for Webinars?
The docs say “string” but provide no max length.
In my testing, Zoom will truncate name to 64 characters and will accept much longer email addresses.
What are the limits to name and email for attendees in Zoom Webinars?

Hey @cholscher,

Thanks for your feedback. @shrijana.g can you help provide the string lengths for these fields?


HI @cholscher and @tommy thanks for bringing this up. The max length for name is 64 chars and email is 128 chars. We have updated the doc to reflect this as well.

Thank you,