My Google Foobar Journey
Created: Nov 14, 2021
Last modified: Oct 28, 2026
This is what Foobar looked like: a little Unix-style terminal running right in your browser,
with commands like ls, cd and cat to find your next challenge.
Google Foobar was a secret, invite-only coding challenge run by Google. You couldn't just sign up for it: it found you. If you searched for programming stuff (algorithms, data structures, that kind of thing), every now and then the page would fold open and invite you to play.
It's wrapped in a fun little story: you're a minion working on Commander Lambda's space station, and every puzzle you solve helps the bunnies escape. Behind the story, though, it's pure algorithms.
There are 5 levels, each with 1 to 3 problems, and they get harder as you go. The clock is always ticking, so you get a deadline for each one:
Level 1: 1 easy problem, 48 hours
Level 2: 2 problems, 72 hours
Level 3: 3 problems, 96 hours
Level 4: 2 hard problems, 168 hours
Level 5: 1 final boss, 336 hours
You could only use Python 2.7 or Java 8, and once you finished every level, Google might reach out to you for an interview.
# My take on it
I went through the whole thing twice. I'll be honest: in the last two levels I had a little outside help. Even so, it was one of the most fun and challenging things I've done as a programmer.
In this section I go through each problem I solved, explaining the idea behind it step by step, with interactive demos so you can play with the solution instead of just reading about it.
And to wrap it all up, a look back at both runs, what was hard and what I learned: Google FooBar: Looking Back.