# String field validation **URL:** \ **Category:** API and Webhooks\ **Created:** [May 5, 2020, 12:19pm UTC](https://devforum.zoom.us/t/string-field-validation/16202 "2020-05-05T12:19:48Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![oori](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/oori/32/6177_2.png) [@oori](https://devforum.zoom.us/u/oori)\ **Post date:** [May 5, 2020, 12:19pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/1 "2020-05-05T12:19:48Z")
Hello 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? - #4 by tommy](https://devforum.zoom.us/t/is-there-a-size-limit-for-the-agenda-field/11199/4) What’s the limit for `first_name` and `last_name` strings? I couldn’t find any documentation of your field validation. That’s missing? Thanks > [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). Thanks. ---
**Author:** ![samly](https://avatars.discourse-cdn.com/v4/letter/s/a87d85/32.png) [@samly](https://devforum.zoom.us/u/samly)\ **Post date:** [May 5, 2020, 1:01pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/2 "2020-05-05T13:01:46Z")
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. ![image](https://us1.discourse-cdn.com/flex016/uploads/zoomdeveloper/original/2X/8/8f88f56b4065a39f8654e78f2545c19ce7710d5a.png) ![image](https://us1.discourse-cdn.com/flex016/uploads/zoomdeveloper/original/2X/d/d9ed77fafe0c9eba1593a28b2757dda7b640a709.png) ---
**Author:** ![oori](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/oori/32/6177_2.png) [@oori](https://devforum.zoom.us/u/oori)\ **Post date:** [May 5, 2020, 1:14pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/3 "2020-05-05T13:14:04Z")
Thanks for your reply. The docs provide the data type, not the validation rules! it just says: “string”. not max-length rule, for example. ---
**Author:** ![samly](https://avatars.discourse-cdn.com/v4/letter/s/a87d85/32.png) [@samly](https://devforum.zoom.us/u/samly)\ **Post date:** [May 5, 2020, 1:14pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/4 "2020-05-05T13:14:57Z")
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: ![image](https://us1.discourse-cdn.com/flex016/uploads/zoomdeveloper/original/2X/d/d9ed77fafe0c9eba1593a28b2757dda7b640a709.png) ---
**Author:** ![oori](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/oori/32/6177_2.png) [@oori](https://devforum.zoom.us/u/oori)\ **Post date:** [May 5, 2020, 1:16pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/5 "2020-05-05T13:16:21Z")
See here: > **[Add Meeting Registrant - Meetings - Zoom API - API Reference](https://marketplace.zoom.us/docs/api-reference/zoom-api/meetings/meetingregistrantcreate)** > > Register a participant for a meeting. > Scopes: meeting:write:admin meeting:write > Rate Limit Label: Light > > Authorization > > Flow: authorizationCode > > Author... ![Screenshot 2020-05-05 at 16.15.50](https://us1.discourse-cdn.com/flex016/uploads/zoomdeveloper/original/2X/c/c2d42524bba57a1e94812d19841f39e519df4025.png) ---
**Author:** ![oori](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/oori/32/6177_2.png) [@oori](https://devforum.zoom.us/u/oori)\ **Post date:** [May 5, 2020, 1:17pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/6 "2020-05-05T13:17:49Z")
Is a first\_name string always 64 characters max-length (as in the screenshot you sent), across the Zoom API ? (webinar, meeting registrants, etc…) ---
**Author:** ![samly](https://avatars.discourse-cdn.com/v4/letter/s/a87d85/32.png) [@samly](https://devforum.zoom.us/u/samly)\ **Post date:** [May 5, 2020, 1:23pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/7 "2020-05-05T13:23:41Z")
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. ---
**Author:** ![oori](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/oori/32/6177_2.png) [@oori](https://devforum.zoom.us/u/oori)\ **Post date:** [May 5, 2020, 1:26pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/8 "2020-05-05T13:26:23Z")
Thanks a lot for your quick and helpful replies. ---
**Author:** ![michael.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/michael.zoom/32/37213_2.png) [@michael.zoom](https://devforum.zoom.us/u/michael.zoom)\ **Post date:** [May 8, 2020, 9:30pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/9 "2020-05-08T21:30:03Z")
@samly thank you so much for your help - we’ll make sure to reflect these consistently across the docs ---
**Author:** ![cholscher](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/cholscher/32/4057_2.png) [@cholscher](https://devforum.zoom.us/u/cholscher)\ **Post date:** [July 21, 2020, 9:23pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/10 "2020-07-21T21:23:03Z")
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?** ---
**Author:** ![tommy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/tommy/32/72769_2.png) [@tommy](https://devforum.zoom.us/u/tommy)\ **Post date:** [July 23, 2020, 9:28pm UTC](https://devforum.zoom.us/t/string-field-validation/16202/11 "2020-07-23T21:28:24Z")
Hey @cholscher, Thanks for your feedback. @shrijana.g can you help provide the string lengths for these fields? Thanks, Tommy ---
**Author:** ![shrijana.g](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/shrijana.g/32/605_2.png) [@shrijana.g](https://devforum.zoom.us/u/shrijana.g)\ **Post date:** [July 24, 2020, 2:43am UTC](https://devforum.zoom.us/t/string-field-validation/16202/12 "2020-07-24T02:43:24Z")
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, Shrijana