Unpaid home assignments are fine, if: - The work produced is not used in any way by the company other than to assess the candidate. - The project has a time l

Unpaid home assignments are fine, if: - The work produced is not used in any way by the company other than to assess the candidate. - The project has a time limit to prevent those with more time to dedicate to it being able to do better (reduces bias). - The company puts time into reviewing the code that is commensurate with the time spent on it (a 3 hour test warrants at least 45 mins of thorough code review and feedback writing across a couple of engineers). - The company provides options to take the test at a convenient time, or even on-site but unsupervised if desired by the candidate. Asking for payment to take part in an interview isn't a great approach assuming the above are true (which they are often not). Companies don't pay for interviews as general rule, but conversely should be clear about the full time commitment so that candidates can make informed decisions about taking part.