Slack Data Engineer Interview Guide
Updated by Slack candidates
Written by Kevin Landucci, Subject Matter Expert, InterviewingThe gist
Though owned by Salesforce, Slack has not lost its DNA: a hip yet thoughtful culture. They don’t have many data engineers, so the ones they have are responsible for quite a huge scale. This is an acquired startup that has done the impossible: stayed themselves and stayed scrappy.
Across tech companies, interview processes range from haphazard and messy to well-structured and quite unbiased. Slack is on the latter side. Candidates report their experience at Slack to be generally positive because of the structure and fairness Slack has implemented. Also, Slack prefers practical questions to theoretical questions.
Not many tech companies include “playfulness” among their top values. Slack does. This lighthearted nature permeates their product just as much as their interview process. Slack is one of those rare companies that is neither a product nor an engineering company; it walks the line between the two quite nicely.
From the sparse publicly available data, data engineers at Slack make an average of $201k-288k in total compensation. But those are very broad starting points. We’re confident that the reality includes much higher figures, especially for engineers at and above the senior level.
This guide was written with the help of data engineering interviewers at Slack.
What does a Slack Data Engineer do?
There are two kinds of data engineers at Slack: those on the core data engineering team and those who are “satellite” data engineers. The satellite data engineers often support a regional team in another city and are responsible for its A/B testing. No matter the type of data engineer, the constant is trying to answer questions like, “How can we increase users' usage of the app?”
The tooling at a company like Slack, compared to a FAANG company, is relatively nascent. For example, at Meta, there is a simple process of backfilling a data pipeline. If something breaks, it’s quite simple to backfill the pipeline with a command-line interface.
But at Slack, the AirFlow team has set it up so that there's restricted access and no command-line backfill tool. So to fix something, you must create a separate backfill pipeline.
Engineers who do well in this environment are more comfortable with the ambiguity of building and fixing data problems without all of the extra structure and tooling you’d get working at the biggest brand-name companies.
Slack doesn’t currently have real-time analytics. They’re aware of this and excited about building it out.
Slack may belong to a Fortune 100 company, but they’re still scrappy. In the interview, broadcast a signal of your own scrappiness to show them you fit in. Stories about doing more with fewer resources will go a long way.
Before You Apply
- Study the interview questions recently asked at Slack.
- Dial in on your data modeling and experimentation skills. These are often reported as the most difficult parts of the interview process.
- Calibrate your presentation to their noticeably friendly interview process; show them the same signal they are trained to give you.
Interview process
Most candidates at Slack report going through an interview process with these 4 phases:
- A recruiter screen to assess your motivation and basic fit
- A technical screen take-home assignment to check for table-stakes technical skills
- A hiring manager screen to measure the scale and complexity of your past work
- Final round interview with 4-6 rounds, mainly with engineers
Recruiter
Slack’s recruiter screen is pretty vanilla compared to most big tech rounds. Candidates often note that recruiters at Slack are more friendly than similar companies. One notable point is that Slack openly declares that it does not care much about formal education; its website explicitly says that it doesn’t care where (or if) you went to school.
Non-traditional candidates are more likely to face friction in many big tech interview processes but less so at Slack. Their focus on reducing bias, undermining pedigree, and practical engineering challenges is a match for engineers with a non-traditional background.
Sample questions include:
- What are your compensation expectations?
- What are you looking for in your next role?
Tech screen
Slack’s tech screen is a practical take-home assignment; they’ll ask you to complete it in a week. Slack goes above and beyond to make sure the graders of these take-homes avoid bias, and this intentionality is found throughout their interview process.
The way these take-homes usually look reflects Slack’s pattern throughout their process: They want to see how you work as a team and measure you on an activity you’d do in a day on the job. They usually give you a pull request and ask you to give feedback on it.
Topics covered:
- Python
Hiring Manager
The interviewer in this 60-minute round could be anyone from an engineering manager to a director. Content-wise, it’s a technical and behavioral round rolled into one. Technical questions will focus on relevant past projects and technologies needed in the position you're interviewing for.
In terms of feel, this is a conversational round. Slack interviewers seem to care more than other interviewers about making candidates comfortable, so the experience of this process is mainly positive. In tech, that’s near-shocking!
Sample questions include:
Asked at - What’s your experience with [technology from the job description]?
Final round
The final interview usually consists of 3–6 one-hour rounds split between experimentation, data modeling (architecture), and behavioral questions.
Interview Questions
Behavioral
Slack’s behavioral screen is focused on teamwork and collaboration. Expect most questions to be about situations from your past and hypotheticals involving interpersonal issues and lessons learned.
Sample questions include:
- When have you had to take on a leadership role?
- Tell me about a time you hurt someone’s feelings.
How many other tech companies will ask you about hurting someone else’s feelings? Only the ones who explicitly search for lighthearted, friendly people. Companies like Slack. And they’re not the majority.
Experimentation
The experimentation round is a high-level conversation about experimentation concepts and scenario-based technical architecture questions. It often presents itself as open-ended trivia-style questions and experiential questions (about your background), oscillating between the two.
If you want to brush up on your experimentation chops, there is probably no better read than Trustworthy Online Controlled Experiments.
Topics covered:
- A/B testing
- P-hacking
Sample questions include:
- At a high level, how have you worked with experimentation?
- How do you define experimentation?
- What is your statistics background?
- What is your experimentation setup? How do you roll out experiments?
Data modeling
This CoderPad round assesses your ability to design a backend data service and make tradeoffs between latency, throughput, and usability. The typical flow is to first design the service and then write some relevant queries for that service. It involves around five different SQL challenges, which increase in difficulty. The first three questions are easy, the fourth question is medium, and the last is medium/hard.
Topics covered:
- Data modeling
- Data architecture
- Project management
- Window functions
- CTEs
- Subqueries
Sample questions include:
- What is the difference between OLAP and OLTP?
- (Easy SQL) Top Earning Employees
- (Medium SQL) Analyze Monthly Customer Transactions
- (Hard SQL) Find Top Customer by Year
Additional Resources
- Brush up on your table stakes skills with our data engineering course.
- Practice with similarly skilled peers in mock interviews.
- Slack’s walkthrough of their software engineering interview process isn’t a 1:1 match for data engineers, but most of it is still quite relevant to data engineering candidates.
- Slack’s engineering blog is playful–on brand–and a solid resource to get a feel for the kinds of projects you can work on there.
FAQs
How should I prepare for a Slack Data Engineer interview?
Focus on sharpening your skills in data modeling, experimentation, and behavioral. Get ready for a practical take-home assignment you’ll have one week to complete.
How much do Slack Data Engineers make?
Most data engineers at Slack make an average of $201k-288k for total compensation. However, there aren’t many data points available, so it’s safe to assume the range goes much higher for roles at and above the senior level.
How long is the Slack Data Engineer interview process?
On par with most other companies of their size and stage, the process at Slack usually takes around a month to complete.
Learn everything you need to ace your Data Engineer interviews.
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