Question: I work on a website where users:

* fill in a registration form (with only 2 fields: password & confirm password; each user have a unique token which is stored in the URL)
* then land directly after on the login page (2 fields again: login & password)

During an UX session with end-users, we noticed that this is a bit confusing to them, because registration form and login form look very similar (two fields). Some users take some time to realize that they're actually on a different page and now need to log in.

In this context, what would be the best solution?

* Create a transition between both screens?
* Automatically log the user in after he sets his password? (This may be a security issue...)
* Somehow differentiate the screens? For example by putting some welcoming message on login page if user just registered...

Thanks in advance, I hope this post is appropriate, first time here.

Answer: 
Just like Mike, I would also find it really annoying if I am asked to sign in again after registering unless there is an email verification that is required.

Another thought - How would you solve cases where a user does not remember if they've previously signed up for the website?

To solve this, I was thinking of a flow where we could replace these two screens '**Registration**' and '**Login**' with this flow - 

* '**Get Started**' screen to input '**Email**' and '**Proceed**' button
* Once user proceeds, we check from backend if the user is a registered user or not
* If the user is not registered, prompt them to enter '**Password**' & '**Confirm Password**'
* If the user is registered, prompt them to enter '**Password**' and allow them to log in.
Personally I find it pretty annoying when I am forced to log in after I've just finished filling in an extensive registration form.  

Nevertheless, have a look at this topic: [Making the user login again after registration](https://ux.stackexchange.com/q/21619/98561) where it is discussed whether or not to automatically log the users in after they filled in the registration form.

In your case, if the registration form consists only of login and password (with confirmation) I would **log the users automatically in**, but (depends on the type of your website):

* offer a somewhat crippled account (e.g. they can search the forum but not post anything) until they validate their account with a link sent by email
* allow them to add items to the cart and allow to make the purchase only after they provide the billing information (can be one of the check-out steps)
* periodically ask them for some more information about themselves (in small chunks) to complete their full profile

If you're concerned about the security (out of scope of this site), I'd rather use session token stored as a cookie instead of an URL token, and provide it as a UUID.  

When the token expires you simply request the login information along with "reset password" option coupled with the email address provided during registration.