Pros
My team and our fearless leader Wall are a joy to work with. Index in general is full of small teams (2-5 people) that on the technical side (the side for which I can speak) take ownership of some part of the product and because of our size into have insight into and experience with other areas of our system too. Wall, Co-Founder and CTO, is the most experienced, articulate, hilarious and quotable boss I've had. Our tech is based on a sophisticated distributed system that he will whiteboard to you for easy understanding. We have virtually no technical debt because Wall drives us to make tough decisions. It's also an exciting time for Index as we've recently found a clear market fit, and big partners in payments, retail, and venture capital are excited for us and helping us grow quickly.
Cons
Index is a young company with very flat organizational structure. At least one previous employee with whom I worked closely found this environment frustrating because he felt the learning opportunities came from a small number of senior employees. Happy hours, advertised as monthly, have become more sparse as there's a lot of work to do. On the other hand, coworkers are very supportive of one another, and unofficial outings after work are more frequent.