You're in the US so this is completely dependent on company policy.
As a general rule, most larger companies do annual reviews and tie any raises to that annual appraisal process. Smaller companies are more likely to not have a formal review process and dole out raises and reviews in a more ad hoc fashion. You may, however, be working for a large company that doesn't have a formal review process or a small company that does. Your company may do annual reviews but adjust compensation separately.
Most companies will have a handbook of some sort that you were given on your first day that spells out how and when reviews happen. If you weren't given such a thing (and no handbook exists online for your company), the best option is generally to talk with your supervisor about the company's approach to reviews of performance and compensation.
Unless something was said about starting you off at a low salary the company said would be adjusted after a probationary period or your duties have expanded significantly from the time you were hired, it seems a bit odd to be concerned about your compensation after just 7 months in what I'm guessing is your first job out of school. For most developer positions, it takes a couple of months to get the new developer up to speed on the existing code base and the company's processes and to get the new developer through the first few easy projects before you start to assign them meatier tasks. At the 6 or 7 month mark, you're generally starting to hit your stride and deliver the value the company anticipated when they made their offer. That's not to say that you shouldn't ask for a raise if you deserve one after your initial 7 months, just to caution you that you'll likely need a particularly compelling argument.