Andrei Istomin

Andrei Istomin

Java/Grails Developer

Velikorita Village, Belarus



What's the difference

Since start of my career I've been using a lot of technologies/languages/frameworks for creation varied types of software in different areas of human life. Last years I'm focused on server side issues, including multi-threading, concurrency and complex business logic problems. Mostly I work with Java technologies(including Grails, Spring, Hibernate and other frameworks).
I like to work with serious, adequate and honest clients. I'm happy if I can help somebody to create something meaningful.


Andrei Istomin has added 6 portfolio pieces. Create an account to review them.

Work History & Feedback

full time position hibernate development

“Andrej is an awesome freelancer. We worked over 1 year together, in total more than 1900 hours. Definitiv one of the best you can hire at upwork, we will continue our collaboration with him. Extremely motivated, Andrej always looks at the goal of the complete company. He perfectly understands complex business logic and helps other developer wherever possible.He is a strong senior java developer and grails master. Andrej likes test drive development and to automate as much as possible. He worked on many different areas, so I can only mention some examples here. He implemented a complex reporting engine that is doing all our data crunching. He wrote a powerful module (separated server) to analyse Millions of records and many tables), queries optimisation, mostly pur sql, but still very flexible code, we can now incredible easy implement new metrics as reporting requirements constantly change. Very strong linux skills as well. Andrej developed and implemented our complete scripted CI (jenkins) test setup, creation of stage / production servers, health checks, autocommits etc. Since one stage system creation involves around 25 repositories, 15 tomcat instances, mysql, activemq and more infrastructure communicating a quite complex system. Thanks to him now all created, tested without manual involvement and triggered by a commit.All our team enjoys working with Andrej, hopes we will stay friends and continue our collaboration for a long time. We want to thank you, Andrej, for your your strong motivation, your productive work and the time we spend together. You have a great impact on our company!”
1,905 hrs

Iphone/Android developer

“Greate worker”
204 hrs @ $16.67/hr
Earned $3,395

Android GPS Location Pusher

“He is very knowledgeable and accomplished the task in a very short period of time. Definitely exceeded our expectations.”
Fixed Price $444
Tests Taken
Name Percentile Score

Java Test


Java Test v3


U.S. English Basic Skills Test