Front End Software Development: 

Javascript (AngularJS, JQuery, D3, Google API's, Prototype, Backbone, GWT), CSS (Bootstrap), HTML5, Objective-C

Android (SDK, NDK, UI/UX Design)

 

Back End Software Development:

Restful Framework, AWS Cluster, Sprint, OSGI, JAX-RS, Java, Python, C/C++, PHP, Ruby, NodeJS, C#/.NET

 

Database, Architecture, and Networking Design: 

Oracle, MySQL, MongoDB, PostgreSQL, HBase, Bigtable, Hadoop, RedShift, GraphDB, DynamoDB

 

Infrastructure/Automation:

AWS, Azure, AppEngine, Ubuntu, RHEL, Memcache, Solr/Lucene, DNS, Load Balancing, Jenkins, Grunt

 

Security:

OAuth1/2.0, Http Basic, LDAP, SSL, Encryption, PCI