Just recently went through a very unusual interview process-- xAI I was interviewed by HR for the position of Software Engineer at a large company. As a NG (new grad) submitting for the first time, I didn't expect much, but HR contacted me, and the whole interview format was quite amazing, totally different from the common big factory interviews. I'd like to share my complete experience with you as a reference for those who are preparing for an interview at xAI or similar startups.
Phone Screen
The store interview can be said to be the shortest and most efficient interview I've ever seen, only 15 minutes before and after, HR came up and emphasized that the answers should be concise, basically "quick questions and quick answers" rhythm.
- Q1: In 30 seconds, tell us about the most technical project you've worked on.
(Amazingly, there's no follow up here at all, it feels like a formality) - Q2: What are the two programming languages you are most familiar with?
- Q3: What deployment to production projects have you done in C++ and Python?
In about 10 minutes, the person asked a dozen or so questions at such a fast pace that there was little time to expand on the details. Instead, I was given 5 minutes to ask questions.
I thought my performance was mediocre, but I unexpectedly received an onsite invitation, and I went to a bare-bones interview (with no additional preparation).
Onsite Interview Process
Round 1: Nine Grids + Trie
The question in this round was "Alphabet Word Search", which is a bit like Boggle, where you are given an NxN alphabet board and a dictionary of words, and you have to find all the words that can be spelled out on the board.
I went straight to Trie + DFS backtracking. trie is used to quickly determine if a prefix exists, and DFS searches the path, pruning off any mismatched prefixes it encounters.
The overall difficulty is medium, not particularly common, but LeetCode brushes up to Word Search II and the like to cover. sort of smooth.
Round 2: LRU Cache
This round is a very classic LRU Cache, requiring the implementation of the get(key) respond in singing put(key, value)The time complexity is O(1).
The standard solution is a hash table + a bi-directional linked table. As a result, I was quick in writing the code and forgot to update the tail pointer in some cases. I wrote my own test case and almost got myself killed.
Here is a reminder: test cases must be written in full, it is best to test while writing, especially corner cases (e.g. cache size=1, repeatedly put the same key, multiple elimination, etc.). Don't wait until the end to test, it will be too late.
Round 3: In-Memory DB with Nested Transaction
The last round was a bit on the system design side: making an in-memory database that supports the SET / GET / BEGIN / ROLLBACK / COMMIT, but also to support nested transactions.
I first wrote the most basic data structure, and then talked with the interviewer with a lot of scaling: for example, if you want to be persistent, you can add logging (WAL) or do snapshots; to consider concurrency control, whether to use locks or optimistic transactions; if you want to scale, you can go distributed or master-slave replication.
The atmosphere is quite relaxed, I feel that the interviewer was already a bit tired at that time, the questions are not standardized like those of big factories, it's more to see if you can think flexibly.
Overall experience
To be honest, the interview process was much more casual and even a bit confusing compared to traditional big companies (e.g. Microsoft, Google). But on the other hand, the atmosphere was very relaxing and not as oppressive as Meta or Amazon.
- Quick questions and answers in the store, focusing on speed of response and clarity of expression.
- Onsite coding difficulty in LeetCode medium ~ medium+ level, basic common topic variants, no particularly sick hard.
- The system design session focuses more on the thought process and the ability to get to the ground than on the only standard answer.
If you want to prepare for interviews like xAI or other startups, we recommend practicing some simplified versions of system design (cache, in-memory store, search trie, etc.) in addition to the basic LeetCode questions.
xAI SWE Interview FAQ
1. Interview process related
Q: What is the interview process for SWE at xAI?
A: Generally it is OA → Technical Interviews (2-3 rounds of coding) → System Design → Behavioral / Culture Fit. The overall process is similar to that of the top Silicon Valley companies, but coding is more practical, system design is more scalability + ML infra, and BQ will involve Elon Musk style "first principles" thinking. The overall process is similar to top Silicon Valley companies, but coding is more hands-on, system design is more scalability + ML, and BQ involves Elon Musk-style "first principles" thinking.
Q: How long is the interview cycle?
A: Usually 2-4 weeks, but if you are hot hiring, it will speed up to 1-2 weeks.
2. Coding Session
Q: How difficult are the code questions?
A: Difficulty and LeetCode Hard Close, with an emphasis on optimization thinking and clean code, looking mostly at data structures (Graph / Heap / Trie / Segment Tree) and algorithms (DP / Greedy / Search / Bit manipulation).
Q: Will there be a test on ML coding?
A: Occasionally, such as implementing a simplified version of the Transformer component, or writing an efficient tokenizer. but mostly they are generic algorithmic questions.
3. System design
Q: What types of problems will the system design favor?
A: Preferences Massively distributed system + AI infra, for example:
- Designing a high-throughput log ingestion pipeline
- Design a model serving system to support real-time reasoning and multi-version A/B testing.
- How to Build Scalable Vector Search Engines
Q: What do interviewers look for?
A: Scalability, low latency, high reliability, data consistency, and the ability to derive system architecture from "first principles" rather than memorizing eight words.
4. Behavioral
Q: What is the focus of xAI's Culture Interview?
A: Elon Musk's team culture emphasizes:
- pursue (a goal etc) first principles thinking(Ability to deconstruct complex problems to their fundamentals and then extrapolate solutions)
- emphasize (a statement) High-intensity implementation(Can the 0→1 program be driven independently)
- right AI and social impact Perceptions (do you truly believe in xAI's mission and not just jumping on the bandwagon)
Q: What are the frequently asked questions?
A.
- Tell me about a time you solved a problem others thought impossible.
- If you had to design an AI system from scratch with limited compute, how would you approach it?
- What motivates you to join xAI over OpenAI/Google/Anthropic?
5. Preparation of recommendations
- brush up on one's studies: LeetCode Hard + System Design case
- Infra knowledge: Familiarity with distributed systems, databases, model serving
- cultural match: Get ready to talk about your long-term vision for AI!
- Practice Expressions: Interviewers like concise, logical explanations and don't like to beat around the bush!
Interviews are never a one-man battle
Programhelp The team consists of mentors from Amazon, Google, Oxford, and other backgrounds, focusing on full-process coaching for OA, VO, and Onsite. Whether it's real-time voice assistance, debug reminders, or mock interview drills, we can help you make less detours in the limited time. Many students rely on this system to successfully get the offer of their favorite company.
