Quick disclosure: I built Grokking the System Design Interview, so I have an obvious bias when comparing it to other resources. The way I've tried to handle that is by focusing on which engineers each resource fits, rather than arguing one is universally better. Hello Interview is a real and respectable competitor. They're doing serious work. The honest version of this post acknowledges that and helps you figure out which one is right for your specific situation.
If you've spent any time researching system design interview prep, you've probably seen Hello Interview come up alongside the usual recommendations: Grokking, Alex Xu's books, Designing Data-Intensive Applications. It's a newer resource than the others, founded by Evan King and Stefan Mai, both ex-Meta and Amazon engineers, and it's built a real following over the past couple of years.
People keep asking which to pick. The honest answer is that they're built for different kinds of learners and different situations. This post walks through who each one actually fits, so you can identify yourself in one of the patterns rather than trying to decide based on feature lists.
The TL;DR
Both are legitimate resources. Pick based on how you learn and what you need.
- Hello Interview fits engineers who want a video-first format, plan to do paid mock interviews with real interviewers, and prefer a smaller, focused content set delivered with strong on-camera presence.
- Grokking the System Design Interview fits engineers who want a comprehensive curriculum across the full system design landscape, value the depth of a 22-lesson trade-offs module, want a tiered path that scales with their seniority (Volume I, Volume II, Advanced), or prefer the structure of a guided curriculum over a video catalog.
- You can use both. Many engineers do. The most common pattern: Grokking as the structured spine of preparation, Hello Interview's mock interviews for live practice in the final weeks.
The rest of this post explains why and when each pattern makes sense.
What each resource actually is
Both are interview prep resources targeting overlapping audiences, but they're structured differently and emphasize different parts of the prep loop.
Hello Interview
Hello Interview is a system design interview prep platform built by Evan King and Stefan Mai, both formerly senior engineers at Meta and Amazon. The platform is video-first, with strong on-camera presentation and walkthroughs of common system design problems. It includes a mock interview marketplace where engineers can book sessions with real interviewers, including current and former hiring managers from major companies.
The mock interview marketplace is a real differentiator. Live practice with experienced interviewers is one of the highest-leverage activities in interview prep, and Hello Interview has built a serviceable marketplace for it. The video lessons themselves cover the standard system design topics with a clear, visual approach.
The content catalog is smaller than Grokking's by total volume but the focus is consistent. Hello Interview is a serious, well-executed resource and it's helped real engineers land real offers.
Grokking the System Design Interview
I created Grokking the System Design Interview in 2018, after years of running system design interviews and watching engineers fail not because they lacked knowledge but because they lacked structure. The course pioneered the pattern-based approach to system design prep, which has since become the standard.
The course includes 66 lessons across 5 chapters: introduction, 20 lessons on system design building blocks, a dedicated 22-lesson trade-offs module, 18 worked case studies, and an appendix with frameworks. It's been studied by over 440,000 engineers across 8 years, is continuously updated, and sits at the center of a tiered curriculum that includes Volume II for senior engineers and the Advanced System Design Interview for principal-level engineers.
The format is a mix of text, video, and interactive diagrams, with AI features that let you sketch your own design and get feedback before watching the lesson's solution.
If you want the full structural breakdown, the curriculum page lists every lesson, and the course overview covers the methodology and history.
Where Hello Interview is the better fit
Three areas where Hello Interview is genuinely the right call for some engineers.
1. You strongly prefer video-first learning
If you learn best from watching someone walk through problems on camera, Hello Interview is built around that format. The presentation is consistently visual and the on-camera voice is good for engineers who absorb material that way.
Grokking has video content for all systems and case studies, but its origin was text-heavy and that DNA still shows. If your strict preference is video-first with minimal reading, Hello Interview is closer to that experience.
2. You plan to use a mock interview marketplace
This is Hello Interview's most distinctive feature. The ability to book sessions with experienced interviewers, including hiring managers from major companies, is genuinely useful and Grokking doesn't have a direct equivalent.
If your prep plan includes 5-10 paid mock interviews in the final weeks before your interview, Hello Interview's marketplace makes that easier to organize. The mock interviews themselves are where the framework knowledge gets converted into framework reflexes under pressure, and Hello Interview's ecosystem supports that step well.
3. You want a smaller, more focused content set
Some engineers prefer a tighter catalog over a comprehensive curriculum. If you'd rather work through 8-10 high-quality video walkthroughs than work through 66 lessons across 5 chapters, Hello Interview's smaller scope may fit your preference better.
This is a real preference and not the wrong choice. More content isn't universally better. It's better for engineers who want comprehensiveness, but worse for engineers who get overwhelmed or distracted by larger curricula.
Where Grokking System Design is the better fit
Five areas where Grokking is genuinely the right call.
1. You want comprehensive coverage across the full system design landscape
Grokking covers more ground in absolute terms. 66 lessons in Volume I alone, 18 worked case studies, and a separate Volume II with 12 additional senior-level case studies. The breadth gives you exposure to more patterns and more problem types, which compounds in interviews where the question is something you weren't expecting.
2. The 22-lesson trade-offs module
This is the single thing I'd point to first as a structural advantage. Grokking has a dedicated 22-lesson module on system design trade-offs covering strong vs eventual consistency, SQL vs NoSQL, ACID vs BASE, push vs pull, stateful vs stateless, REST vs RPC, token bucket vs leaky bucket, and many more. Each gets a full lesson explaining when to choose which.
Senior-level interviews are won and lost on trade-off conversations. Most resources cover trade-offs lightly across other topics. Grokking is the only resource I know that builds an entire module around them as a skill in their own right.
3. A tiered curriculum that scales with your seniority
Grokking is structured as multiple courses for different career stages:
- Up to 5 years of experience: Grokking the System Design Interview alone is sufficient.
- Senior engineers (5+ years): add Grokking the System Design Interview Volume II for deeper case studies, plus Grokking the Advanced System Design Interview if you have time.
- Principal+ engineers: all three above are required, plus Grokking Microservices Design Patterns if your role involves microservice architecture.
Hello Interview doesn't have an equivalent tiered structure. Their content is one body of material rather than a curriculum that progresses with your career stage. For engineers at the senior or principal level specifically, this is a meaningful difference.
4. Track record, authorship continuity, and continuous updates
Grokking the System Design Interview has been studied by over 440,000 engineers across 8 years. The course pioneered the pattern-based approach to system design prep, and the methodology hasn't pivoted between versions. Recent 2026 updates include AI features that let you sketch your own design before watching the solution, an expanded trade-offs module (10 to 22 lessons), and Volume II with 12 new case studies on systems that have been showing up in 2025-2026 interviews. For more on what's new, see the 2026 update post.
A reader who buys access in 2026 gets a course that's been refined for 8 years and continues to evolve.
Which fits you specifically
Different engineers have different needs. Here's how I'd actually advise people based on what they're optimizing for.
Engineers preparing for a specific upcoming interview, 4-8 week window
Either resource works as primary preparation. The decision comes down to format preference. Video-first learners often pick Hello Interview. Engineers who want comprehensive curriculum and don't mind text-and-video format pick Grokking.
If you're going to use paid mock interviews as part of your prep (recommended either way), Hello Interview's marketplace integrates that step. If you're sourcing mock interviews independently, the marketplace advantage matters less.
Senior engineers (5+ years) targeting L5+ roles
I'd lean toward Grokking here, primarily because the tiered curriculum (Volume I + Volume II + Advanced) is built to scale with seniority. Senior-level interviews probe trade-offs and architectural depth that the 22-lesson trade-offs module covers more systematically than what's available elsewhere.
Hello Interview can supplement this with mock interviews. The marketplace is a useful complement to deep curriculum work.
Principal+ engineers
Grokking is the more direct fit because the curriculum extends through Advanced and Microservices Design Patterns, which is what principal-level interview prep typically requires. Hello Interview's content doesn't extend as deep into principal-level architectural reasoning.
Engineers who learn primarily from video, or who want a structured curriculum
Format preference often decides this. Hello Interview's video-first format suits engineers who absorb material best from on-camera walkthroughs. Grokking's curriculum suits engineers who want a path with clear progression rather than a video catalog. Neither preference is wrong; they just lead to different fits.
Can you use both?
Yes, and many engineers do. The combinations that actually work:
Grokking as the spine, Hello Interview mocks as practice. Use Grokking to learn the framework, fundamentals, trade-offs, and case studies. Use Hello Interview's mock interview marketplace in the final 2-3 weeks for live practice. This combination works because the resources serve different parts of the prep loop: Grokking teaches, Hello Interview practices.
Hello Interview as primary, Grokking's trade-offs module as supplement. If you've already started with Hello Interview and want deeper trade-off coverage, the trade-offs module in Grokking is available, including in the free tier. This serves engineers who like Hello Interview's format but recognize the trade-offs gap.
What I wouldn't do: take both end-to-end as primary curricula. The fundamentals coverage overlaps significantly, and you'd be spending preparation time on a second pass through familiar concepts when you could be practicing instead.
How this compares to other comparison questions
If you're also considering Alex Xu's books or Designing Data-Intensive Applications, those comparisons exist separately:
- Grokking vs Alex Xu's books for the most popular book alternative.
- Grokking vs Designing Data-Intensive Applications for engineers comparing against Kleppmann's textbook.
- Is Grokking the System Design Interview Worth It? walks through five questions for engineers still deciding whether to enroll in any course.
Frequently Asked Questions
Should I use Grokking the System Design Interview or Hello Interview?
Depends on what fits how you learn and what you need. Hello Interview suits engineers who prefer video-first learning, plan to use paid mock interviews, or want a smaller content set. Grokking suits engineers who want comprehensive curriculum, value the trade-offs module, need a tiered path that scales with seniority, or prefer guided structure. Neither is universally better.
Can I use both Grokking and Hello Interview?
Yes. The most common combination is using Grokking as the structured curriculum and Hello Interview's mock interviews for live practice in the final weeks before an interview. The two resources serve different parts of the prep loop and complement well.
Which one is better for senior engineers?
I'd lean toward Grokking for senior engineers, primarily because the tiered curriculum (Volume I, Volume II, Advanced) is built specifically to scale with seniority. Hello Interview can supplement this with mock interviews, but the structured progression for senior interview prep is more developed in Grokking's catalog.
Does Grokking have mock interviews like Hello Interview?
Grokking doesn't have an equivalent in-house mock interview marketplace. Engineers using Grokking typically source mock interviews independently or through other platforms. If a mock interview marketplace is core to your prep plan, Hello Interview's offering is more directly integrated.
Is one better for FAANG interviews specifically?
Both have helped engineers land FAANG offers. Grokking's pattern-based methodology and trade-offs module map well to FAANG scoring rubrics. Hello Interview's mock interview practice is useful for the communication-under-pressure dimension that FAANG interviews score heavily. Either resource, studied thoroughly with mock interview practice, prepares you for FAANG-level system design rounds.
Related reading
- Grokking the System Design Interview vs Alex Xu Books: An Honest Comparison. Comparison with the most popular book alternative.
- Grokking the System Design Interview vs Designing Data-Intensive Applications. Sequencing post for engineers considering DDIA.
- Is Grokking the System Design Interview Worth It? A Decision Framework. Five questions to answer before deciding to enroll.
- Grokking the System Design Interview Review: An Honest Look from the Person Who Built It. Detailed review of the course's strengths and weaknesses.
- The Full Curriculum. All 66 lessons with one-line descriptions.
Try the free tier first
The most reliable next step is the free tier on DesignGurus.io. Spend 30 to 60 minutes with the introductory content to confirm the format works for you. Pair that with watching some Hello Interview content to see which presentation style fits how you learn. The format preference is the single biggest factor in this decision, and you can evaluate it without paying.