Choosing the best professional to bring your project to life is a crucial decision that can significantly impact the success of your endeavors. As a business owner or project manager, you might find yourself on the brink of hiring a Ruby on Rails (RoR) developer. But how do you ensure that you select the right person for the job?

Ruby on Rails, also known as Rails, is a server-side web application framework written in Ruby under the MIT License. It follows the Model-View-Controller (MVC) architectural pattern, providing default structures for a database, a web service, and web pages. It's a highly productive and extremely popular framework among developers due to its efficiency, speed, and simplicity.

However, the mere knowledge of RoR doesn't guarantee that a developer is the right fit for your project. To make an informed decision, you need to ask specific questions that will help you gauge their skills, experience, and compatibility with your project requirements.

• How would you handle data flow in a Ruby on Rails application?

Data flow is a critical aspect of any application. It refers to how data moves through an application, from the user interface to the back-end databases and vice-versa. Understanding how a potential developer would handle data flow can give you insights into their understanding of MVC architecture, and their ability to manage, manipulate and maintain data effectively.

• Can you share your experience with Test-Driven Development (TDD) and Behavior Driven Development (BDD) in a RoR framework?

TDD and BDD are software development techniques that aim to improve the quality of the software. In TDD, developers first write tests for the functionality they want to implement, then write code to pass those tests. BDD, on the other hand, focuses on the behavior of an application for end users. A developer's experience with these techniques shows their commitment to delivering high-quality, efficient software.

• What are the security measures you would implement in a RoR application?

Security is a non-negotiable requirement in today's digital landscape. RoR has various built-in security features, but it's essential to know if the developer understands these features and how they can be utilized to ensure maximum security. This can range from preventing SQL injection to cross-site scripting.

• What gems have you used in your past RoR applications?

Gems are libraries of Ruby code that developers can use to add functionalities in their applications without coding from scratch. However, each gem comes with its own set of pros and cons. A developer's familiarity with different gems can reflect their ability to leverage existing solutions and their understanding of potential trade-offs.

• Can you describe a challenging project you've worked on, and how did you overcome those challenges?

This question is insightful in two ways - it allows you to assess the developer's problem-solving skills and their ability to work under pressure. A developer that can narratively explain how they approached and solved a complex problem can demonstrate their thought process, tenacity, and commitment to delivering results.

• What is your approach to debugging in Ruby on Rails?

Debugging is an inevitable part of the development process. A developer's approach to debugging can indicate their analytical skills, patience, and persistence, which are all essential qualities for problem-solving.

Remember, the ultimate goal is to find a developer who aligns with your project requirements and organizational values, and is capable enough to turn your vision into a functioning reality. These questions are intended to serve as a guide to help you in your selection process. By probing into these particular areas, you'll be better equipped to differentiate between candidates and choose the right Ruby on Rails developer for your project.