Outsourcing software development

We have used outsourced developers to supplement our main development team for various projects over the years.

It's important that your interview process is rigorous with real-world problem solving conducted over a number of hours.

Secondly, you should use a verified third-party automated time keeping system if you are paying per hour. This ensures that you pay for the time that is worked, and there is a reasonable degree of trust maintained (see e.g. WiseTime: https://headwise.systems/product#wisetime).

You should ensure that you take proper measures to protect your IP:
i) ensure that any IP generated is assigned to your company in the contract
ii) modularise your code, and only allow contractors to work on at most n-1 modules (so that no external contractors have all of the source code that enables the product to function)
iii) use automated code quality tools such as findbugs, checkstyle, PMD, minimum test coverage, and reject commits that do not meet the standards specified, by using a CI server such as Bamboo or Jenkins

If you are a start-up, you may not want to do that now. The rates are lower, but in our experience you need to take extra time into account that is increased when the cultural difference is bigger. As a start-up you probably want to develop at a high pace. Then it is recommendable to keep the communication barrier as low as possible. If you cannot hire the appropriate skill profile in Germany or Austria, you might want to try Eastern Europe or the Balkan first. They have lower rates, good work attitude and are in the same time zone and cultural region.