I´m designing an extranet module for vendors that want to return and exchange unwanted products (change size or color, return broken products, etc.).

I have to validate the identity of the vendor (via SMS, mail or id card number) before sending the request.

Is it better to validate identity before starting the all process that is an extended form? or is it better to let the user complete the form and validate identity at last...just before sending the request?

Thanks for your time!....

  • Would there ever be a reason to allow them to fill out the form (create an account?) and do the validation another time? Is there a concept of an "unvalidated" account? Jan 29, 2018 at 5:46

3 Answers 3


My initial response is to validate before starting the process. What if they don't pass validation? They just wasted a lot of time on a process that they ultimately were not going to be able to complete. Validate before the process so there isn't any doubt or future frustration.

  • Thanks Tory... but...why do not use the same criteria as in an ecommerce? i mean.. let them do the process...just ask for validation at last?... I think this validation process is more a security issue that in most of cases should be ok because is an extranet (you've already login to be at this point)
    – assu
    Oct 6, 2016 at 21:59
  • 2
    If "validation" was something they might fail (like a credit-check), then definitely do so up-front to avoid wasting both sides' time. If (as it seems) it's more a confirmation process, then providing you can remember the data until the confirmation has happened then doing it either before or after would be fine.
    – TripeHound
    Aug 2, 2017 at 10:01

You need to understand 2 things. 1. Possibility 2. Probability

Yes it's possible that users might fill out the whole form and then fail to authenticate. That's a possibility. But how likely is this to happen? 20% of the times? 50% of the times?

That'll tell you the probability of this possibility.

And your decision should totally depend on that.


Most designs allow the user to fill out the form before validation. This is common on one-page designs, where most of all fields are visible and accessible to your client. That's fine and in this case you would definitely validate at the submission.

Other designs are tabbed or a lead-in process, where the user must enter their username/email & password pair for validation before proceeding to the rest of the form, by which is usually also in page-by-page form to keep a "horizontal-thinking flow" and that is also okay to do.

That's 2 common use cases. So either way is acceptable, but I believe it depends on the style or design of the forms your speaking of, one is a single vertical page, the other is a series of pages.

Alas, there is my favorite: Option 3.

Let's say you want it simple, one page to do it all. And let's say that you want it to be validated, but want them to be able to fill out the form hassle-free. This can be done too. How? On-the-fly / real-time validation.

The proper way would most likely be to write Ajax or JavaScript/jQuery that upon password field unfocus, sends both the username/email &a password fields to the server for verification, then display the results:

"*Account Validated" in green "*Username/Email & Password do not match" in red (optionally you could change the account fields to those colors as well)

Essentially I'm suggesting that instead of choosing to do validation before or after the process, you do so during it. You don't have to worry about people wasting time filling it out only to find out that it didn't pass, nor if their browser will remember their field information (if that's also a concern). And it doesn't break the movement of the page, it all happens without taking them anywhere else. A jerk-free experience is a plus!

This is the way a lot more people are doing it lately and it seems to address both concerns in one solution. Yes, it is rather more complex, but the payoff of having done it and being able to do it again, as well as happy clients, is priceless!

Best of luck and hope you find success!

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