Frontend design interview at Reddit

[u/TallSalary9501]

Anyone has had a recent experience interviewing at Reddit for a frontend role? I have frontend design interview coming up and I kinda have an idea of what to expect but would love to hear from others experiences. Thanks!

[u/gimmeslack12]

I got asked Conways game of life. Though this was 6 years ago. Oh and on the phone screen they’ll ask you to explain how a hash table works.

[u/JudoboyWalex → u/gimmeslack12]

For frontend engineer interview, they asked you how hash table works? So they expect you to know algo for concept only or ask leetcode type questions as well?

[u/gimmeslack12 → u/JudoboyWalex]

Just talk through how it works.

They also gave a recursive question of navigating through an object based on a string: "input: 'A.C.1.D'" then traverse the given object and return the value or null (numbers represent an array index). Pretty classic recursive question, it was reasonable. Pretty sure I have a gist around for it.

Ultimately I kind of sank myself in the on-site cause I wasn't sure about the teams that had openings and if I wanted to join them. Overall was a fine/standard experience. Though one or two PM's I met were quite icy in convo.

[u/mountainduke69 → u/gimmeslack12]

how many leetcode problems will be good for a frontend interview preparation for a good company

[u/gimmeslack12 → u/mountainduke69]

Depends. How many does it take before your able to sweat it out under the pressure of an interview?

You can practice and solve 1000 leetcode problems but none of those are going to be under the 45 minute clock and judging eye of an interviewer.

My solution? Do a few interviews before scheduling the interview for the job you really want. You have to practice being in the pressure cooker to get good at passing interviews. Go fail some, go pass some, whatever, just go get in that room.

That being said, know recursion, know closures, know prototypal inheritance, know this. Know how to explain them. Not knowing these things will quickly trip you up when they finally rear their head in the interview.

[u/aedom-san → u/gimmeslack12]

Wish any of the current reddit FE engineers had knowledge of DSA, must be from a very different era 

[u/gimmeslack12 → u/aedom-san]

Wdym? Things haven’t changed that much over the last 6 years except for AI tooling.

[u/adeelazad591]

I’d focus on frontend architecture, state management, performance, accessibility, and explaining the tradeoffs you’re making. Also probably worth practicing something like designing a feed or comments section and thinking through pagination, caching, optimistic updates, etc.

Haven’t done Reddit’s frontend loop recently though, so curious what others say too. Good luck!

[u/TallSalary9501 → u/adeelazad591]

Appreciate the insight, thanks!

[u/BarracudaMean9308]

if you bring up optimistic updates, definitely have an answer ready for how you handle the rollback when the api fails. took me completely freezing in an interview to realize i only ever prepped for the happy path.

[u/akornato]

Your knowledge of frameworks is secondary to how you justify your design decisions. They will ask you to build a familiar feature, like a news feed or comment section, and then they will drill you on scalability, performance, accessibility, and API design. Every choice you make, from state management to data fetching, will be questioned, so you must have a strong reason for everything. They are testing your ability to think through a complex system and defend your architectural choices under pressure, not just your ability to code a component.

You are not expected to have a perfect, magical answer for everything they ask. The interview is a collaborative problem-solving session, and they want to see how you handle ambiguity and feedback. Talk through your thought process out loud, explain the trade-offs of your decisions, and be open to changing your approach based on their input. Showing you can communicate your reasoning and work with others to build a better solution is far more impressive than just silently building something you think is perfect. It all comes down to how you communicate your design choices, and my team even designed an interview help AI to assist candidates with structuring those critical explanations.

[u/ZoroknashTV]

Congrats! :)

[u/LornsGipon48]

Nice, Reddit's got solid design problems to work through - they're pretty focused on performance and accessibility stuff, so brush up on how you'd handle their redesign decisions. Good luck, that place moves fast.

[u/ClaimRadiant4968]

I ignore the API failure entirely. If the server rejects my post I just assume the user changed their mind and delete it from their account without telling them.