How to mark Trello fields as required

Sometimes you may want to have fields that users are required to fill in.  For example if you have cards representing customer requests this each request should have the customer name.

Although Trello does not have a way to prevent a card from being created, Amazing Fields has a simple way to help.  You can setup background color rules to change the color of the field if it has an empty value.  For example the text field below has been configured to be red if it is empty.

When the user creates a new card they will immediately see a red field that they should fill in.

This will also show up on the front of the card to alert them that there is key information missing.

The same technique can be used for other field types and values.  For example you may have a number field that only makes sense if the value is > 10.  You can create a styling rule to change the color and mark fields that don't have valid data.  This method is simple but very effective.