Substack's Interview Process (2026)

Blog / Substack's Interview Process (2026)
Substack Interview Process
Substack's software engineer interview process is structured and moves at a reasonable pace, typically wrapping up within three to four weeks from first contact to offer. Most candidates go through a recruiter screen, a technical phone screen, and a virtual onsite loop, though the exact format can vary by role and team.
  • Recruiter Screen: A 30-minute call to talk through your background, your interest in Substack's mission around independent publishing, and basic logistical fit.
  • Technical Phone Screen: A live coding session of around 60 minutes in a collaborative editor, typically focusing on data structures and algorithms at a medium difficulty level.
  • Coding Rounds (Onsite): Two separate coding sessions during the virtual onsite, continuing the DSA focus but sometimes including real-world scenarios like building a small feature or debugging a provided codebase.
  • System Design: An architectural discussion where you're usually asked to design systems relevant to Substack's scale, such as a newsletter delivery pipeline or a social feed.
  • Craft Deep-Dive: A round unique to Substack where you walk through a past project in depth, with interviewers looking for your technical judgment, trade-off reasoning, and attention to the quality of the end product.
  • Behavioral / Culture Fit: A conversation with an Engineering Manager or product partner focused on how you think, how you communicate, and whether your values align with Substack's culture of independent thinking and agency.
To prepare effectively for Substack's process, it helps to break your study plan into a few focused areas that reflect what the interviews actually test:
  • Data Structures & Algorithms (DSA): LeetCode-style coding questions at the medium difficulty level, often framed around Substack-relevant concepts.
  • System Design: Architectural design questions focused on Substack's scale, including newsletter delivery, social feeds, and payment systems.
  • Craft Deep-Dive: A project-based round that evaluates your technical taste, ownership, and ability to reason through trade-offs in past work.
  • Behavioral: Culture and values conversations that reward independent thinking, clear communication, and demonstrated agency.
1. Data Structures & Algorithms (DSA)Substack's coding rounds tend to sit at the medium difficulty level, with problems often framed around product concepts like follower graphs, social feeds, or subscription logic. You won't usually see pure algorithmic puzzles in isolation; expect the problem to have some product context attached to it.Graph traversal is a recurring theme given Substack's follower network structure. Brushing up on graphs and related traversal patterns is a solid starting point. Rate-limiting algorithms and feed-related data manipulation also come up in candidate reports.Interviewers at Substack reportedly value a clean, working solution over a partially optimized one. Test your code carefully before declaring it done, and talk through your logic as you go. Working through our top 100 DSA questions is a good way to build that foundation systematically.Substack's tech stack is primarily TypeScript and Node.js, so being comfortable with asynchronous programming patterns will serve you well during coding rounds. If you want to sharpen your approach on array and feed-manipulation style problems, our arrays topic is a good place to start.
2. System DesignSubstack's system design round focuses on real problems the company actually faces, so generic prep alone won't cut it. Expect prompts like designing a newsletter delivery pipeline that scales to 10 million or more subscribers per send, or designing something similar to Substack Notes as a short-form social feed.You'll want to think carefully about the two-sided marketplace dynamic: writers produce content and earn revenue, readers discover and consume it. High-concurrency email delivery, Stripe payment integration, and feed ranking are all fair game. Practicing on our System Design Whiteboard is a great way to get comfortable structuring these kinds of architecture discussions out loud.Because Substack is a remote-first, writing-heavy company, how clearly you communicate your design decisions matters as much as the design itself. Review the core ideas behind High-Level Design and practice narrating your trade-offs, not just drawing boxes. If you want to practice a closely related prompt, our News Feed (Twitter, X) walkthrough is directly applicable to the Substack Notes design question.
3. Craft Deep-DiveThis round is Substack-specific and unlike anything you'll see at most other companies. You're asked to walk through a complex project you've built, and interviewers are looking for what they call 'software taste': your sense of craft, your attention to detail, and whether you genuinely care about the quality of what you ship.Choose a project where you had real ownership and can speak to specific technical trade-offs you made. Vague answers like 'we chose Postgres because it's reliable' won't land well. You want to be able to say something closer to 'we chose X over Y because of the specific impact it had on latency under our write load.'Prepare two or three strong 'war stories' and practice telling them out loud. Think about what problem you were solving, what options you considered, why you made the calls you did, and what the end result looked like for users.
4. BehavioralSubstack values independent thinking and agency, so behavioral questions here tend to probe for times you took initiative without being told to. Generic teamwork stories won't stand out; look for examples where you identified a problem on your own and drove it to resolution.Structuring your answers using the STAR format keeps your responses focused and easy to follow. Given that Substack has a strong writing culture, clear and concise communication during this round matters more than it might elsewhere.Our Behavioral Interview Course covers the frameworks you need, and the Behavioral Playbook is useful for building out a bank of strong stories before your interview.
ConclusionSubstack's process rewards candidates who prepare with genuine product curiosity, solid fundamentals, and a real sense of craft in their engineering work. Start with your DSA foundations, build out a few strong system design narratives, and pick your best project story for the Craft round. Follow the Substack Interview Roadmap for a structured, step-by-step plan that covers every stage of the process.

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