Databricks interview notes, page 14 of 22

Large Enterprises

Most of these Databricks write-ups come from Software Engineers (192), then Machine Learning Engineers (9) and Data Scientists (8). The most reported rounds are the technical phone screen (136), the system design round (57), the behavioral / leadership round (9) and the onsite coding round (6).

216 interview notes · updated Jul 2026

Databricks·Software Engineer·Technical Phone Screen

Jun 2026

Databricks technical phone screen with a networking/IP routing problem that sounds deceptively simple until you realize they want a full trie implementation. Pretty standard for the level but the longest-prefix-match angle threw me a bit.

Given a list of CIDR rules each tagged as approve or reject, and a query IP address, determine whether the IP is approved or rejected using longest-prefix-match semantics. If no rule matches, default to reject.

“I parsed the CIDR blocks into integer intervals first, which worked for basic membership checks but felt clunky when they asked about efficiency at scale.”

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Databricks·Software Engineer·Technical Phone Screen

Jun 2026

Databricks system design phone screen, pretty focused on a single data structure problem that spiraled into concurrency territory. The core question was manageable but the follow-ups on lock-free design were where things got uncomfortable.

Design a hit counter that tracks the number of hits in the last 5 minutes. Implement a hit(timestamp) method to record a hit and a getHits(timestamp) method to return the count within the sliding window.
How would you extend this hit counter to support higher time granularity, and how would you make it thread-safe or lock-free under concurrent writes?

“The circular buffer approach clicked for me pretty fast.”

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Databricks·Software Engineer·Technical Phone Screen

Jun 2026

Databricks SWE interview that went deep on networking fundamentals pretty fast. The core problem was ACL rule matching and it escalated into range intersection territory which I was not fully ready for.

Given a list of ACL rules where each rule is a CIDR block and an action (ALLOW or DENY), implement a function that takes an IP address and returns the matching action based on rule order.
Follow-up: instead of a single IP, the input is a CIDR block representing a range of IPs. Return ALLOW only if every IP in that range is allowed by the ACL. How do you approach this efficiently?

“The CIDR bitmask part I actually got through okay.”

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Databricks·Software Engineer·Technical Phone Screen

Jun 2026

Databricks coding screen, one question, sliding window. Pretty standard stuff but worth writing up since the problem has a few gotchas if you're not warmed up on frequency maps.

Given two strings, determine whether any permutation of the first string appears as a substring of the second string.

“Classic sliding window with a character frequency array.”

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Databricks·Machine Learning Engineer·Technical Phone Screen

Jun 2026

Databricks ML Engineer screen, one meaty coding question about implementing linear regression from scratch with gradient descent. No ML libraries allowed, which sounds easy until you're actually deriving the gradients on the spot and someone's watching.

Implement simple linear regression from scratch using gradient descent. No sklearn or torch, numpy is fine. You need to define the model, use MSE loss, derive and implement the gradients for both weights and bias, build the training loop with configurable learning rate and iteration count, and then discuss how you'd choose the learning rate, when to stop training, and how to detect if the model is diverging.

“The coding part I was fine with.”

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Databricks·Software Engineer·Technical Phone Screen

Jun 2026

Databricks software engineer interview with a networking-flavored coding problem. The question was about building a CIDR block lookup system that returns the longest-prefix match for any incoming IPv4 address, basically a mini router in code. Felt like a solid systems-adjacent problem, not your typical LeetCode grind.

Design and implement a class that takes a list of IPv4 CIDR blocks at construction time and, for any given IPv4 address, returns the most specific (longest prefix length) matching CIDR block from the list, or an empty string if none match.

“The problem looks like a networking thing at first and I spent a minute mentally panicking about whether I needed to remember subnet math.”

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Databricks·Software Engineer·Onsite - Cross-functional / Panel

Jun 2026

Panel exercise for a Solution Architect role at Databricks. One hour to build and pitch a FinServ MVP, then field questions from a panel. Intense but fair.

Build and pitch an MVP on Databricks for a financial services use case. Your pitch should cover the value proposition to the customer, the full architectural design (ingestion through Delta Lake layers to ML/analytics and BI), governance via Unity Catalog, and a live demo.
How does your design handle data security and compliance requirements typical in financial services?
What are the latency characteristics of your proposed architecture, and where are the bottlenecks?
Walk us through the cost model for running this architecture at scale. How would you justify the spend to a FinServ customer?
How does your design support regulatory audit requirements? Can you trace data lineage end to end?

“This was the whole exercise basically.”

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Databricks·Software Engineer·Technical Phone Screen

Jun 2026

Databricks SWE interview with a networking/IP problem that looked simple but required you to actually know how CIDR masks work under the hood. One question, pretty focused, felt more like a technical phone screen than a full onsite loop.

Given a single IPv4 address and a list of CIDR blocks, return the first CIDR block in the list that contains the given IP address, or null if none match.

“I knew what CIDR was conceptually but blanked for a second on how to actually compare the bits programmatically.”

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Databricks·Software Engineer·Technical Phone Screen

Jun 2026

Databricks software engineering interview where the real test wasn't the algorithm, it was figuring out what to do when the interviewer nudges you in a direction you weren't planning to go. Uncomfortable situation and I don't think I handled it perfectly.

During a coding problem, the interviewer offers a hint that seems to point toward a different approach than the one you're already working on. How do you decide whether to follow the hint or stick with your current direction?
How do you communicate your thought process and reasoning to the interviewer while still making forward progress on the problem?

“This one messed with my head more than any actual algorithm question.”

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Databricks·Software Engineer·Technical Phone Screen

Jun 2026

Phone screen for a software engineer role at Databricks, centered entirely on a system design question about building a book seller platform. Pretty standard format, one meaty design problem, no behavioral or coding.

Design a book seller platform.

“This is the kind of question that looks straightforward until you start talking and realize you haven't thought about half the pieces.”

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