Developed small to medium sites for the web. The most successful product currently has approx. 20k active users.
Used php, node.js, some scala and a bit of java.
Dived into DevOps, got familiar with AWS and docker.
Designed and implemented the better part of expatconnect.com, which is a social site for expats in Dubai, backed by a handful of services. Put it back on track (in collaboration with a few awesome colleagues) after a miserable failure and various performance issues. Learned the importance of resiliency (the hard way).
Helped to save over $10k in connection with a compromised AWS key pair.
Developed a reasonable security policy afterwards, which prevents further incidents.