There are several factors you should consider before hiring a software developer. Some of them are below:
1. Location: Are you going to hire an onshore or offshore developer? If you want to remotely work with the developer than location does not matter. Offshoring project may save the overall cost of the project. If you want to meet in person to the developer, you should hire a software developer in your nearby location.

2. Development Charges: What are the rates of a software developer? If you are working on an hourly basis, you should check what hourly rates are applied by the software developer.

3. Relevant Experience: Check if developer has worked on similar project that you have? Also, how many years of experience they have?

4. Ask them to provide you sample work: Many times, you want to check the code writing skills of a developer? You can ask them to provide you sample code before starting the project.