Coding fluency
Implement an LRU cache. Explain your data structures, test capacity one, and walk through an eviction.
What a strong answer demonstrates
Correctness, edge cases, and time / space complexity.
Prepare for Fastly with a focused mix of coding, design, and communication. Start with your job description and confirm the interview loop with your recruiter.
6 Practice picks
2 Interview reports
5 Levels mapped
01 / MAKE YOUR NEXT SESSION COUNT
Your preparation, made concrete.
System design
Design a notification service. Clarify delivery guarantees, model the data, then handle retries and duplicate events.
What a strong answer demonstrates
Clear requirements, a working baseline, and explicit trade-offs.
Behavioral storytelling
Describe a technical decision you changed after receiving feedback. Explain your contribution and the outcome.
What a strong answer demonstrates
Specific actions, honest reflection, and measurable impact.
BEFORE YOU PRACTICE
Ask your recruiter.
Get the details that a generic company guide cannot know.
- Which team and level is this opening for, and what does success look like?
- What rounds, durations, and evaluation criteria should I prepare for?
- Which languages, tools, and AI assistance are permitted?
- Will design focus on frontend, backend, infrastructure, or another specialty?
- Are there accommodations or preparation materials I should request?
Fastly practice problems
Company-linked challenges and related lessons from our library. Not a prediction of your interview.
Challenge
Difficulty 6/10
Length of String Compression
Challenge
Difficulty 4/10
Missing Number In Unsorted
Challenge
Difficulty 5/10
String From Binary Tree
Challenge
Difficulty 7/10
Nth Smallest Number in a Stream
Challenge
Difficulty 5/10
K Largest Elements From List
Challenge
Difficulty 8/10
Convert Number to Words
Real interview experiences
2 reports from candidates who interviewed at Fastly.
What people at Fastly say
Reviews originally posted on Glassdoor.
Thoughtful, evolving product offered that helps everyone who hosts or uses a online content. The company has strong values in cultivating talent and letting our efforts shine. Cares for the employees. Very pandemic friendly company who accommodates to our needs.
The CEO is great and demonstrates strong values.
Perfect work/life balance, management is very understanding and accommodating. A lot of project opportunities, interesting scaling issues to work on and a lot of freedom on how to tackle those. Great team spirit too.
One Friday off a month during work from home due to COVID, they are called wellness days.
Delivery product works quite good.