In Pokemon Go, IV (Individual Value) is associated with CP of Pokemon. Selecting Pokemon with higher IV is important to win gym battles. Pokemon Go Nexus helps a player know IV of all stocked Pokemon. If you are not sure what is IV in Pokemon Go, see the link below.
To use Pokemon Go Nexus, a player need to get token which is issued by OAuth to prevent a password leaking. However, using the tool is your own responsibility. On the Pokemon Go Nexus page, there is a message as below.
By using this site you agree that its service is provided as-is.
We make no guarantees it is allowed under Niantic's terms of service.
We are not responsible for anything that may happen to your account due to the use of this site.