Rails Interview Questions
I get a fair number of questions via Hacker Hours and elsewhere regarding what questions to use/expect in an interview for a Rails developer, so figured I would get it together in a tidy list. Pull requests welcome.
- Personalize your list of questions.
- Don't ask questions you don't know the answers to.
- Mix trivia questions with open-ended ones.
- Use Codr or a similar online collaborative text editor for doing coding challenges
- Can be seen in real-time by remote team members
- The unique URL with the solution can be easily sent around or added wherever you a tracking information about the candidate
- About a third of the way through the interview, however you're feeling about the candidate (
👍/ 👎), try and convince yourself otherwise.
- This is to help yourself fight your own biases.
- Don't study to the test. Not all of these questions will be used, and others will be asked that aren't covered here. Know your stuff.
- Rails skills != CS skills
- Know whether you are interviewing for a full-stack vs. backend-focused position.
- Have code up on Github/Bitbucket/wherever - the more side projects you have to talk about, the better.
- Be comfortable with some version control system.
- Community awareness and resourcefulness can be as important as technical knowledge.
- What is a tree? What is a DAG?
- Pseudo-code depth-first and breadth-first search.
- Given a sorted array, what is the fastest way to find a element? What is the Big-O time to do so?
- Explain how ajax works, hitting all parts of the stack. (@abestanway)
- What is the difference between a lambda, a block and a proc? [I have gotten this one at every Ruby interview I've been in]
- How do you sort an Array of objects by a particular attribute? What is a better way to do sorting with ActiveRecord?
- What are some of your favorite gems? What are their alternatives?
- In Ruby, which is generally the better option: a recursive function or an iterative one?
- What are
#send? Why are they useful?
- What are the various Ruby runtimes, and how are they different?
- What is the general history of Rails?
- What is new in Rails 4?
- Explain the different pieces of Rails.
- Walk through the flow of a request through Rails.
- What are the different server options for running a Rails/Rack app?
- Explain CSRF and how Rails combats it.
- Explain mass-assignment vulnerability.
- Why do some people say "Rails can't scale"?
- What is Rack?
- What is middleware? How does it compare to controller filters/actions?
- Explain various forms of caching available in Rails.
- What are some Ruby web server options?
- How is something like
30.seconds.agoimplemented? (c/o @harrisj)
- On a scale of "I've heard of it" (0) to "I maintain it" (10), how would you rate your Rails proficiency?
(no particular order)
- @darcyclarke's Frontend Interview Questions (inspiration for this repo)
- Video of the Junior Developer Panel that I hosted
- Ruby Koans
- Project Euler
- Flatiron School Prework and background
- Job Interview by @ruby-jokes
- Developer Evangelist Interview Questions
- Resources from Hacker Hours
- Technical interview cheat sheet