Production and Developer orgs and Sandboxes, oh my! Do you have too many Salesforce logins to keep track of? Maybe you’re an admin doing some customizations and testing with your users. You’ve got a personal Developer org to play with, a Dev Sandbox for building, a Full Sandbox for UAT, and don’t forget Production. And since they weren’t all created at the same time, your password changes on varying schedules, so you can never remember which password goes with which username. Or maybe you only have one org and just don’t want to waste your time entering your username and password every time you sit down at your computer. Your head is spinning and you wish there was an easier way to just get where you need to go. Well, you can log in to every one of your orgs with just the click of a button with this simple trick!
Start with the standard login URL (login.salesforce.com for dev orgs and production, test.salesforce.com for sandboxes). Now add /?un= followed by your username, then immediately after &pw= followed by your password. The end result should look like this: https://email@example.com&pw=password. Now just save this link to your browser (assuming it is secure), and you can log in to all of your orgs with just the click of a button! Remember that sharing this link or using it on an unsecure browser is like sharing your login credentials, so be sure to follow best practices.
-Jared and the Salesforce Guys