My favorite platforms for coding and system design mock interviews.
Hello friends, I want to tell you something I don’t share often, because it still stings a little.
A few years ago, I interviewed for Google Bangalore. I felt ready. I’d solved hundreds of LeetCode problems, gone through every system design resource I could find, and had years of engineering experience. I even write on Medium. I was confident.
I didn’t make it past the first few rounds.
What I didn’t do — and what I think cost me that opportunity — was mock interviews. I thought I knew the answers. I could rehearse solutions in my head. What I didn’t account for was how different it is to actually articulate your thinking under pressure, in real time, to a real person asking real follow-up questions.
That gap between knowing something and being able to demonstrate it clearly in an interview is exactly what mock interviews close. And I only learned that the hard way.
If you’re preparing for FAANG interviews, I’m sharing this so you don’t repeat my mistake. Do mock interviews before the real thing. Btw, if you are in rush and an interview coming today/tomorrow, just go ahead and join Exponent, one of the best mock interview platform. It also got 5 free sessions with peers.
Interview prep for product, engineering, data science, and more – Exponent
7 Best Mock Interview Platforms for System Design and Coding Interviews in 2026
Here are the 7 best platforms to do exactly that in 2026 — with Exponent at the top, because it’s the one I’d recommend first based on my own experience.
1. Exponent — Best Overall Mock Interview Platform
Exponent is the platform I’d recommend first, and the one I find myself pointing people to most often when they ask about mock interview prep.
What makes Exponent stand out is the combination of expert coaching, structured peer interviews, and a community that’s genuinely engaged in helping each other prepare.
The peer mock interview feature is free — which removes the cost barrier entirely for getting real, human practice under interview conditions. For paid sessions, you’re connecting with experienced professionals who’ve been on both sides of FAANG interviews.
The Software Engineer Interview Course is also excellent — one of the most comprehensive interview prep courses I’ve seen, covering both coding and system design with the kind of structure that makes preparation feel manageable rather than overwhelming.
Key features:
- Free peer-to-peer mock interviews — connect with other candidates and take turns interviewing each other
- Expert coaching sessions — connect with professionals from top companies for mock interviews, resume reviews, or personalized study plans
- Discounted 5-session package — buy in bulk and use sessions at your own pace
- Tailored matching — get matched with the right coach based on your target role and specific needs
- System Design Interview Course specifically focused on this hardest round
The free peer mock interview feature alone makes Exponent the most accessible starting point on this list. If you’re early in your preparation and want to understand what you don’t know yet, book a peer session on Exponent this week.
Here is the link to Start with Exponent Mock Interviews
Mock Interviews: Improve Your Skills By Practicing with Peers and AI – Exponent
2. DesignGurus.io — Best for FAANG-Expert System Design Mocks
When it comes to system design interview preparation, DesignGurus needs no introduction — their Grokking courses (Grokking the System Design Interview and Grokking the Advanced System Design Interview) are the most widely used system design prep resources in the industry.
What fewer people know is that DesignGurus also offers mock interviews conducted by experienced FAANG engineers — including the authors of the Grokking courses themselves. That’s a meaningful differentiator.
When Arslan Ahmad, who literally wrote the book on system design interview prep, is giving you feedback, you’re getting insight calibrated to exactly what FAANG interviewers are looking for.
How it works:
- Purchase and schedule your mock interview through this link
- Engage in fully anonymous virtual sessions with experienced FAANG engineers
- Choose coding mock, system design mock, or both depending on your needs
- Receive personalized written feedback highlighting strengths and areas for improvement
- Get a customized learning plan based on your specific gaps
Post-interview benefits: Personalized, in-depth feedback and customized learning material for continuous improvement leading up to your real interview.
Here is the link to Purchase a DesignGurus Mock Interview
3. Educative Mock Interviews — Best AI-Powered On-Demand Practice
If scheduling is a challenge — or if you want to practice more frequently than any single coaching platform makes financially practical — Educative’s AI-powered mock interviews are one of the strongest options in 2026.
With over 18,000 mock interviews already conducted on the platform, the AI has been trained on enough real interview data to genuinely simulate FAANG-level system design sessions.
It asks intelligent follow-up questions, challenges your design decisions, and adapts to your responses rather than following a fixed script.
The interactive diagramming workspace is particularly valuable — you can actually sketch your architecture during the mock, just as you would in a real interview.
What makes it stand out:
- AI interviewer that understands your answers and probes deeper — not a chatbot reading from a script
- Interactive diagramming workspace for real system design practice, not just verbal explanation
- Deep performance analysis across System Architecture, Technical Design, Trade-off Analysis, and Communication
- Role-targeted questions — SDE-2, SDE-3, Engineering Manager, etc.
- Instant, actionable feedback immediately after each session
Many users note that the AI is more patient than human coaches and delivers more structured feedback — making it especially effective for practicing the explanatory part of system design where most people underperform.
Best for: Unlimited, on-demand practice without scheduling friction — especially effective for system design explanation and trade-off discussions.
Here is the link to Try Educative Mock Interviews
Mock Interviews for Software Engineers
4. Bugfree.ai — Best AI-Powered System Design Mock with 150+ Problems
Bugfree.ai is the platform that branded itself as “LeetCode for System Design” — and it earns that description. The combination of 150+ curated system design questions with AI-powered mock interviews creates a complete active-practice environment that goes well beyond what reading or watching videos can give you.
The AI adapts to your responses with intelligent follow-up questions that probe your reasoning, challenge your trade-off decisions, and push back on your assumptions — closely simulating what experienced FAANG interviewers actually do.
The instant, detailed feedback on solution structure, communication clarity, and diagram quality gives you specific things to work on after every session.
Key strengths:
- 150+ curated system design questions with step-by-step solutions from top companies
- Realistic AI mock interviews that ask follow-up questions, probe trade-offs, and challenge design decisions
- Instant detailed feedback on structure, communication, diagram clarity, and technical depth
- Support for interactive diagramming during mock sessions
- Personalized scenarios based on your target company and role
- OOP Design and Behavioral interview practice as well
Best for: Developers who want focused, high-quality system design mock interviews with realistic pressure and immediate feedback. Free trials are available.
Here is the link to Try Bugfree.ai Mock Interviews
Master System Design & Behavioral Interviews Like Leetcode
5. Codemia.io — Best for Peer Mock Interviews + System Design Practice
I found Codemia.io when I was looking for system design practice problems — essentially LeetCode but for system design questions. Since then it has expanded significantly: DSA practice, OOP design problems, and now a peer mock interview feature that I’ve found genuinely valuable.
The peer mock interview on Codemia is elegantly simple. Add your available times, browse slots created by other candidates, book a slot, and join the video call at the scheduled time.
You take turns interviewing each other. That’s it — but the simplicity is deceptive. I tried it recently and learned more in 90 minutes than in the two weeks of solo study that preceded it.
Why? Because you can rehearse a system design answer in your head and feel ready, but the moment you have to articulate it to a real person who can ask “why did you choose that database?” or “how would this handle 10x traffic?” — the gaps in your thinking become immediately visible. That’s irreplaceable practice.
How it works:
- Add your available times or browse slots created by other candidates
- Book a slot that works — you’ll be matched with the creator
- Join the video call at the scheduled time and take turns interviewing each other
Here is the link to → Book Your First Mock Interview on Codemia.io
AI Mock Interviews for Software Engineers
6. InterviewKickstart — Best for Real FAANG Expert Interviews
InterviewKickstart is the premium option on this list — and it earns that positioning by offering something the other platforms can’t: mock interviews conducted by actual FAANG+ hiring managers, not just FAANG engineers or AI systems.
The difference between an engineer and a hiring manager giving feedback is meaningful. Hiring managers know exactly what gets a “hire” vs. “no hire” decision, what differentiates candidates at the margin, and what specific signals they’re looking for that most interview prep resources don’t teach.
They offer two packages:
Essential Pack: Single mock interview with full support, personalized written feedback, progress tracking, and access to curated prep guides.
Elite Pack (recommended): Three mock interviews with comprehensive support including resume review, LinkedIn optimization, skill gap analysis, target role insights, salary benchmarks, and lifetime access to all interview recordings. Currently offering 30% off.
Yes, it’s more expensive than the other options. But a FAANG opportunity is genuinely rare — most people get one, maybe two real shots in their career. Against that context, the cost is minimal.
Here is the link to Explore InterviewKickstart Elite Pack (30% OFF)
Ace your mock interview | Interview Kickstart
7. Meetapro — Most Affordable Expert Mock Interview Platform
Think of Meetapro as the Airbnb for mock interviews — it connects job seekers directly with experienced interviewers from FAANG and other top companies, at prices that are significantly lower than traditional coaching platforms.
The direct connection model is what makes Meetapro unique. You communicate directly with your interviewer before and after the session, which allows for a personalized experience that scheduled platforms often can’t replicate. The all-in-one tooling (including session recording for review) makes it easy to get maximum value from each session.
Why choose Meetapro:
- Lowest average session cost among expert interview platforms on this list
- Direct communication with your interviewer before and after sessions
- Expert interviewers with real FAANG experience, not just general coaches
- All-in-one tools including the option to record and review your performance
- Accessible for candidates who want expert feedback without paying premium prices
→ Try Meetapro Mock Interviews
MeetAPro – Mock Interviews with Industry Professionals
Which Platform Should You Use?
Different situations call for different approaches. Here’s my honest recommendation:
Start here if you’re on a budget or early in prep: Exponent’s free peer mock interviews. Zero cost, real human practice, available immediately. This is where I’d tell any candidate to begin.
Use this for unlimited AI practice: Educative or Bugfree.ai. Both offer on-demand AI mock interviews that you can do as often as you want without scheduling or cost-per-session constraints.
Use this for expert system design feedback: DesignGurus.io. When you want a FAANG engineer who wrote the definitive system design courses to review your answers and give you a personalized learning plan.
Use this before your real interview: InterviewKickstart. When you’re within 2–4 weeks of your target interview and want the highest-quality human feedback from actual hiring managers. Worth every penny at this stage.
Use this for affordable expert access: Codemia.io. The best price-to-quality ratio for human expert sessions on the list.
Codemia | Master System Design Interviews Through Active Practice
The Right Study Approach
Mock interviews are the final piece of a preparation process that also needs:
Structured learning:
- ByteByteGo for visual system design concepts
- Grokking the System Design Interview for structured problem coverage
- Mastering the System Design Interview by Frank Kane on Udemy for comprehensive video prep
- Software Design and Architecture Specialization on Coursera
Active practice:
- Codemia.io for LeetCode-style system design problems
- Grokking Modern System Design for Software Engineers & Managers on Educative
- Web Application & Software Architecture 101 on Educative
Mock interviews: Use the platforms above. Do at least 2–3 before your real interview, ideally with a mix of AI (for quantity and immediate feedback) and human (for realism and nuanced coaching).
Final Word
I missed a FAANG opportunity because I was overconfident and skipped mock interviews. I thought studying was enough. It isn’t — not for interviews this competitive.
The platforms above solve the specific problem that LeetCode and online courses can’t: they put you in an actual interview environment, force you to articulate your thinking under pressure, and show you the gaps between what you know and what you can demonstrate. Those gaps are what cost candidates their offers.
Don’t make my mistake. Pick one platform from this list and book your first mock interview this week. Your future self will thank you.
All the best with your interviews.
P.S. — If you’re going to do one thing right now, schedule a mock interview on Codemia.io or Exponent with ex FAANG expert. The personalized feedback from someone who literally wrote the definitive system design interview courses is worth more than weeks of solo study. You can thank me later.
Codemia | Master System Design Interviews Through Active Practice
I Missed a FAANG Offer Because I Skipped Mock Interviews — Don’t Make the Same Mistake was originally published in Javarevisited on Medium, where people are continuing the conversation by highlighting and responding to this story.
This post first appeared on Read More