Programing Language: Ruby, Java, Javascript
Databases: MySQL, Oracle, MongoDB, DynamoDB
Search Engine: Elastic search
Cache Engine: Memcache, EHCache, Redis
Framework: Spring MVC, Strust 2, Ruby on Rails
Infrastructure: AWS (EC2, ECS, ECR, Lambda, ELB, SQS, SNS, EC2
Auto Scaling, VPC, R53 and so on ), Docker
Others: Chef, Treasuredata, Sidekiq, Jenkins, Shell script and so on.