1. What is a Software Engineer?

As a Software Engineer at Whatnot, you are not just writing code; you are building the infrastructure for the fastest-growing live shopping platform in North America and Europe. Whatnot blends community, commerce, and entertainment, creating a unique real-time marketplace where users buy and sell everything from trading cards to fashion through live video auctions. This role places you at the intersection of high-concurrency distributed systems, real-time video streaming, and complex marketplace logistics.

In this position, you will drive the technical direction for critical product surfaces, such as the Discovery Platform, Seller Tooling, Trust & Safety, or Payments Infrastructure. You will work in a high-velocity, remote-first environment where engineers are expected to have strong product instincts. Unlike traditional engineering roles where you might only execute a spec, at Whatnot you will partner closely with product and design to shape features that support millions of users and process thousands of transactions per second. You will be solving problems related to latency, scalability, and user engagement, directly impacting the livelihoods of sellers who turn their passions into businesses.

2. Common Interview Questions

These questions are based on real interview experiences from candidates who interviewed at this company. You can practice answering them interactively on Dataford to better prepare for your interview.

3. Getting Ready for Your Interviews

Preparation for Whatnot requires a shift in mindset. You are interviewing with a company that values "cream of the crop" talent and emphasizes autonomy. While technical prowess is the baseline, your ability to think like a product owner is equally critical.

Key Evaluation Criteria:

Technical Fluency & Speed Interviews will test your ability to produce clean, production-ready code quickly. You will be evaluated on your command of data structures (particularly hashmaps and arrays) and your ability to navigate a Python-centric backend environment (though other languages like Elixir and Go are valued).

Product Sense Uniquely for an engineering role, Whatnot evaluates your "Product Sense." Interviewers want to see that you understand the user journey. You should be able to discuss why a feature should be built, not just how. You will be assessed on your ability to make trade-offs between technical perfection and business value.

System Design & Scalability Given the real-time nature of live auctions, you must demonstrate proficiency in designing systems that handle high throughput and low latency. You will be evaluated on your knowledge of distributed systems, database choices (Postgres, DynamoDB), and real-time data processing.

Cultural Principles Whatnot places a heavy emphasis on their cultural values, specifically "Low Ego" and "Impact Driven." You will be evaluated on how you collaborate, how you handle feedback, and whether you prioritize moving the business forward over personal technical preferences.

4. Interview Process Overview

The interview process at Whatnot is rigorous, streamlined, and moves quickly. It typically begins with a recruiter screen to assess your background and alignment with the company's hubs (San Francisco, LA, NY, Seattle) or remote expectations. Following this, the first technical hurdle is almost always a Karat interview. Whatnot utilizes Karat, a third-party interviewing service, to conduct the initial technical screen. This round usually involves a mix of project discussion and coding problems.

If you pass the Karat round, you will move to the Virtual Onsite stage. This loop is comprehensive and generally consists of three to four distinct rounds: a live coding session with a Whatnot engineer, a system design interview, a product sense/product design interview, and a final behavioral round focused on engineering principles and culture.

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The timeline above illustrates the typical flow. Note that the Reference Check stage at Whatnot is distinct; candidates frequently report that references are requested and contacted before a final offer is extended, which is a deviation from the industry standard. Be prepared to provide manager references earlier in the closing process than you might expect.

5. Deep Dive into Evaluation Areas

The evaluation at Whatnot is designed to find engineers who are both deep technical specialists and broad product thinkers. You should prepare to be tested on the following core areas:

Coding & Algorithms (Karat & Internal)

The coding rounds focus on practical problem-solving rather than obscure brain teasers. You will likely face a Karat interview first, followed by an internal round. The difficulty generally ranges from LeetCode Medium to Hard.

Be ready to go over:

• Data Structures: Deep familiarity with Hashmaps, Arrays, and Strings is essential.
• Logic & Control Flow: Questions often involve parsing data, validating strings, or managing state in a game-like scenario.
• Test Cases: You are often expected to write your own test cases or debug code within an IDE that may not have built-in test suites.
• Advanced concepts: Recursion and Graph traversal (BFS/DFS) appear occasionally, but core data manipulation is more common.

Example questions or scenarios:

• "Implement a function to validate a specific string format or parse a log file."
• "Solve a multi-part coding question involving hash map lookups and data aggregation."
• "Refactor a piece of code to handle edge cases regarding user permissions."

System Design

For mid-level and senior roles, system design is a "make or break" round. You will be asked to architect a system relevant to Whatnot’s domain—think high-concurrency, real-time interactions.

Be ready to go over:

• Real-time Systems: How to handle live comments, bids, or video streams.
• Database Design: Schema design for e-commerce (Orders, Inventory, Users) and choosing between SQL vs. NoSQL.
• Scalability: Handling "thundering herd" problems during a high-profile auction drop.
• Advanced concepts: WebRTC, Pub/Sub architecture (Kafka), and caching strategies (Redis).

Example questions or scenarios:

• "Design a Spotify music uploader system."
• "Design a real-time notification system for millions of users."
• "How would you architect a leaderboard for a live auction?"

Product Sense

This is a differentiator for Whatnot. You will face a round specifically designed to test your product intuition. This is not a coding round; it is a discussion about features, user experience, and prioritization.

Be ready to go over:

• User Empathy: Identifying user pain points in a buying/selling flow.
• Feature Prioritization: Deciding which features to build first for an MVP.
• Metrics: Defining success metrics for a new feature (e.g., retention, conversion rate).

Example questions or scenarios:

• "How would you improve the seller onboarding experience?"
• "We want to add a new social feature to the live stream. How would you design it and measure its success?"

Behavioral & Principles

This round, often with a Hiring Manager or Engineering Leader, assesses your fit with Whatnot's values. They are looking for "low ego" and high autonomy.

Be ready to go over:

• Conflict Resolution: Disagreeing with a PM or designer.
• Ownership: Times you took a project from 0 to 1 without much guidance.
• Past Projects: A deep dive into a specific project you listed on your resume (often the first 15 minutes of the Karat interview as well).