Summary
I recently completed my onsite interview for a Software Engineer role at Benchling, which involved a comprehensive five-round process focusing on practical engineering challenges like system design, debugging and extending algorithms, and implementing JSON validation without external libraries.
Full Experience
High-level Thoughts
I really enjoyed this onsite process. All interviewers were very sweet, attentive to my questions, and keen to understand my thought process. I appreciated the appropriate hinting provided, and the general enthusiasm for Benchling's mission among the staff. The interviews were unique, focusing on productive engineering discussions and product thinking rather than standard LeetCode problems.
Round 1: Product Demo (20 minutes)
This round required no specific preparation. A Software Engineer showcased a small product demo, simulating a toy science experiment on Benchling. The demo covered tools like the lab notebook and DNA sequence viewer. I had ample time to ask questions about the demo and the product.
Round 2: Data Architecture
Part 1: My task was to model the schema for the Lab Notebook product. After a small demo and aligning on requirements with the interviewer, I used standard class syntax to propose my schema.
Part 2: The discussion then moved to supporting versioning of lab notebooks. I had to talk through the actual database storage and how I would handle various use cases. I felt the discussion on the trade-offs between storage and compute was very productive, and I was able to propose a solution that the interviewer seemed happy with.
Round 3: Coding 1
I was provided with existing code for a search algorithm. My initial goal was to get the existing unit tests to pass, which involved fixing a few bugs such as minor index updates and initialization issues. Following this, I needed to extend the system to support a new type of search query. I managed to implement about 50% of the approach and felt I was heading in the right direction. I didn't quite finish the last step of implementing the feature, but I convinced the interviewer that I could complete it with 5-10 more minutes. It was emphasized that I wasn't expected to finish all parts of the question.
Round 4: Coding 2
I was given a set of JSON structures and tasked with validating them against a schema. The critical constraint was coding in Coderpad, which meant no additional Python dependencies like pydantic or marshmallow were allowed. I was able to come up with a pretty robust system. However, I didn't get all the JSON type validation logic in place as the interviewer engaged me with questions about improving my interface. I found this problem very interesting, and similar to Coding 1, full completion wasn't expected; the interviewer cared more about my thought process.
Round 5: Behavioral
This was a casual chat with the hiring manager. I was asked pretty standard behavioral questions, and we did a brief deep dive into one of my complex projects. This included discussing my role, the project's duration, and what I might do differently. I thoroughly enjoyed this conversation, and the hiring manager answered my clarifying questions about the company and team's goals very well.
Interview Questions (4)
I was tasked with modeling the database schema for a 'Lab Notebook' product. After aligning on requirements from a small product demo, I proposed a schema using standard class syntax. The discussion then moved to supporting versioning of these lab notebooks, requiring me to talk through database storage strategies and trade-offs for handling various use cases in terms of storage and compute.
I was provided with existing code for a search algorithm and its unit tests. My initial task was to debug the system to make all existing unit tests pass, which involved minor fixes like index updates and initialization errors. Subsequently, I needed to extend the search algorithm to support a new type of search query. I managed to implement about 50% of the approach and was confident I was on the right track, assuring the interviewer that I could finish the feature with a few more minutes. It was mentioned that one isn't expected to finish all parts of the problem.
I was given a set of JSON structures and had to implement a system to validate them against a schema. The constraint was coding in Coderpad without the ability to install external Python dependencies like pydantic or marshmallow. I developed a robust system but didn't complete all JSON type validation logic, as the interviewer engaged me with questions about improving my interface. Similar to Coding 1, full completion wasn't expected, with a greater emphasis on the thought process.
This was a casual conversation with the hiring manager. I was asked standard behavioral questions and we did a brief deep dive into a complex project I had worked on. This included discussing my role, the project's timeline, and what I might do differently if given the chance. I also had the opportunity to ask clarifying questions about the company and team goals.
Summary
I had a collaborative phone screen at Benchling where I designed a traffic light system for a 4-way intersection, focusing on readable and maintainable code rather than LeetCode-style optimization.
Full Experience
This phone screen was a really fun and collaborative round for me. I was happy to work with the interviewer like colleagues on an interesting problem. We weren't allowed to use AI in this round, which was clearly stated.
The main task was to design a traffic light system for a standard 4-way intersection. I focused on communicating my assumptions based on real-world understanding to the interviewer, and he was very patient and attentive. The only follow-up question I got was about how I would improve the code prior to submitting it for review, which led to a good discussion.
Overall, I really liked this round and felt very relaxed. The interviewer was super nice and listened attentively.
Interview Questions (1)
You have a standard 4-way intersection (think the shape of a "plus"). You need to design a traffic light system. No starter code provided, just the requirements:
- Assume a standard traffic light system (red, yellow, green)
- A technician that maintains the traffic lights should be able to control the duration of yellow and green
- You need to implement a function that takes in
num_tickswhich is a positive integer and for each "tick", output the light color for the traffic lights in the intersection. - Anything you'd expect in a real traffic light system is fair game and should be accounted for. Do communicate your assumptions though
The expectation:
- Don't focus on time and space complexity here like you'd do in a LeetCode problem.
- You should optimize for writing readable, maintainable, and extensible code like you would in a real engineering setting.
Preparation Tips
My preparation for this round centered on thinking about good design principles rather than typical LeetCode algorithm optimization. I focused on communicating assumptions clearly, designing maintainable and extensible code, and using appropriate OOP concepts for interfaces and data representation. The key was to write readable code as if for a real engineering setting, rather than just demonstrating algorithm knowledge.