The issue I have with places that expect you to write functions and solve complex problems off of the top of your head is that they prove nothing. You might be

The issue I have with places that expect you to write functions and solve complex problems off of the top of your head is that they prove nothing. You might be able to write a complex sorting algorithm but you might also struggle to work under pressure, you might struggle at coming up with solutions for simple problems by overcomplicating things and taking longer which in turn yields a more complex and working end-result but cost the company twice the amount of money it should have. Interviews should be a lot more simple. How about sitting the potential candidate down after validating their resume and skill-set meets the requirements of the role with your developers and have them help the team out for an hour or two and see how they go. There are many other factors to consider like; are you a good fit for the team (personality wise especially), are you able to adapt to other coding styles and conventions you might not be accustomed to? As Albert Einstein once said: "Never memorize what you can look up in books" — Google is the 21st century equivalent of a book. Why remember what you can Google? You might not know how to write that complex algorithm off of the top of your head, but that shouldn't matter. What should matter is knowing what to search via Google or a book to solve the problem. As a web developer who uses a plethora of languages like PHP, Ruby, Javascript (Node.JS and jQuery), CSS, HTML and Python it's a given you won't know how to do everything. I consider myself pretty knowledgeable but the things I don't know, I Google. The difference between a good developer and a bad developer is whether or not you have the skills to find the answers to your problems not whether or not you know the answers off of the top of your head. Another approach when hiring someone is sitting them down and ask them to build something, not solve a mathematical problem but actually build a website application or software application. Interviewing a web developer? Ask them to build a simple blog application or script that interfaces with the Twitter API and fetches 10 Tweets based on a hashtag... That's my take on it anyway.