Translation of websites and apps, despite its popularity, is one of the most difficult and challenging type of translation that exists in the market of translation services.
If you are looking for reliable and experienced workers, translation bureau can guarantee you the quality of the professional document translation, for example you can try this one service - https://2polyglot.com. But there is also a possibility of hiring the freelancers, smart and open-minded people with excellent knowledge of the language and sufficient experience who are always ready to perform the job at the highest level. When working with a translator without a mediator, you can control the process and make changes if you are not satisfied with something.
Do you work for 2polyglot? 
Sometimes I work there as freelance translator.
What exactly are you interested in?