We've been around for the better part of a decade and are completely open source (and free). Everything from our clients (which a lot of the community started) to every piece of the server. The only code you don't get access to is our billing infrastructure.

We're also fortunate to call many of the biggest names in Silicon Valley (as well as outside) our customers.

What you'll quickly find is anything that looks like Sentry, acts a lot like Sentry, and usually was inspired by Sentry. What you'll also discover is that even with this in mind, they are far from the same level of maturity. For example, we've spent a lot of time tuning our grouping algorithms, expanding support for power users, and generally solving problems that aren't obvious until you've invested a lot of time into using the tool.

This is a long winded way of me saying that Sentry is the best in the business.