Ask engineers what the best interview prep app is and you'll mostly hear one answer: LeetCode. That's a reasonable answer for the coding screen and an incomplete one for the whole loop.
Here's the part that gets underweighted. At mid-level and above, the coding rounds mostly decide whether you clear the bar. The behavioral round, the "walk me through the most complex project you've worked on" deep dive, and how well you explain your design trade-offs decide which level you're offered, and sometimes whether you get an offer at all. Leveling turns on scope, ownership, and judgment far more than on whether someone solved the graph problem.
This comparison is written from the hiring side, by a former Google, Amazon, and Adobe hiring manager who has run 1,000+ interviews. Coding practice is well served, and you should use the tools built for it. For the rounds where you have to talk, Revarta is the best fit, and it doesn't pretend to be a coding judge.
Quick start: Try Revarta free. Answer "tell me about the most technically complex project you've led" out loud, then compare the feedback with what ChatGPT says about the same answer.
What software engineering interviews actually test
Before comparing tools, it helps to look at what a typical onsite or virtual loop covers. These are editorial estimates for a mid-level to senior loop at a large tech company. Startups and new-grad loops vary.
- Coding (35-50%). Data structures and algorithms, usually in a shared editor or CoderPad-style environment. Filters candidates, but doesn't level them. This is where most prep hours go, and the tools are excellent.
- System design (20-30% at mid-level and above). Designing a service end to end. The content half is about knowing the building blocks. The communication half is about scoping, stating trade-offs, and responding when the interviewer pushes back.
- Behavioral (15-25%). Conflict, failure, ambiguity, influence without authority, disagreeing with a manager. Amazon interviewers also assess you against its Leadership Principles. This is where leveling decisions get made.
- Project deep dive (10-20%, often merged into behavioral). "Walk me through the most complex system you've built." Interviewers keep asking "why" until they find out what you personally decided and what the team decided.
Coding has the most tools and the least differentiation. The other three are spoken, judgment-heavy, and under-practiced, so that's where better prep moves the outcome.
Quick comparison
| App | Best for | Spoken practice + feedback | Coding depth | Price |
|---|---|---|---|---|
| Revarta | Behavioral, project deep dive, explaining design trade-offs | Hiring-manager-calibrated, voice-first | None (no code execution) | $39/mo, $99 for 90 days, $349 lifetime |
| LeetCode | Coding drills, company-tagged problems | None | Excellent | Free tier; Premium about $35/mo or $159/yr |
| NeetCode | Structured algorithm roadmap with video solutions | None | Very good | Free roadmap and videos; Pro $119/yr or $297 lifetime |
| Hello Interview | System design content and guided practice | AI tutor, not spoken mocks | Some coding content | Free guides; Premium $47/mo, $79/yr, $279 lifetime |
| interviewing.io | Anonymous mocks with senior engineers | Human, high quality | Strong | Free AI interviewer; human mocks from $179 |
| Aced (formerly Exponent) / Pramp | Courses plus free peer mocks | Peer feedback, variable | Good | Free peer mocks; paid plans, check current pricing |
| Final Round AI | Live-interview copilot | Real-time suggested answers | Some | Free plan; Pro from about $25/mo |
1. Revarta: best for the rounds that decide your level
What it is. A voice-first AI interview coach built by a former Google, Amazon, and Adobe hiring manager who has run 1,000+ interviews. You speak your answers out loud and get feedback calibrated to what a hiring manager is actually listening for, not to whether your answer sounded polished.
How it works for engineers. Paste the job description and your résumé. Revarta builds a job-specific prep plan: a fit score, your strengths and gaps for that role, the likely interview rounds with interviewer personas, and company research. Then you practice:
- Full mock interviews against those rounds, spoken out loud, with feedback after each answer.
- Single practice questions when you want to drill one weak story.
- Story Builder, where a voice coach helps you turn real projects into STAR stories and maps them to the questions you're likely to get.
- A coach that follows up between sessions, so prep keeps going after the first evening.
What the feedback catches. These are common failure patterns in engineering loops:
- "We" with no "I." A migration story where the interviewer can't tell what you decided. At senior levels, it's a frequent path to a down-level.
- Scope that doesn't match the level. A senior candidate whose best story is a well-executed ticket rather than a cross-team problem.
- Trade-offs left out. "We chose Kafka" without the alternatives you rejected and why.
- Conflict stories where you're quietly the villain. Engineers often pick a conflict story in which they were right and everyone else was slow. Interviewers hear it differently.
- No measurable result. Latency, cost, incidents, adoption. If you shipped it, say what it changed.
What it doesn't do. Revarta does not execute code or grade algorithm solutions, and it isn't a whiteboard tool for drawing architectures. For system design, it's useful for the spoken part: scoping out loud, defending trade-offs, and handling "what happens when this goes down?" Learn the building blocks elsewhere.
Pricing. $39/month, $99 for 90 days, or $349 lifetime (see plans). Free to start with 2 full mock interviews and 2 practice questions. The Job Description Decoder and Tell Me About Yourself builder are free with no signup.
Best for. Mid-level to staff engineers going for a level up, engineers back on the market after a layoff, new grads with thin story libraries, and anyone facing an Amazon, Google, or Meta behavioral round. Role-specific question sets: software engineer, AI engineer, DevOps engineer.
Try Revarta free: practice your project deep dive out loud →
2. LeetCode: best for coding drills
What it is. The default problem bank for coding interviews, with thousands of problems, an in-browser judge, contests, and a Premium tier that adds company-tagged problems.
Strengths. Problem volume, a fast judge, discussion threads with multiple solutions, and company tags. Nothing else has this much breadth for algorithm reps.
Limitations. Silent practice. You type, the judge passes or fails you, and nobody hears you explain your approach, which is half of what a live coding interviewer scores. No behavioral or project-story prep.
Best for. Everyone with a coding round. Premium is worth it in the weeks before a specific company's loop. Check current pricing; recent reviews list it at about $35/month or $159/year.
Stop Guessing. See Exactly How You Sound.
Reading about interviews won't help you. Speaking out loud will. Your first few interview practices on us.
Get specific feedback on what's working and what's killing your chances. Know your blind spots before the real interview.
3. NeetCode: best structured algorithm roadmap
What it is. A curated roadmap of problems (the NeetCode 150 builds on the Blind 75) with clear video explanations, plus a Pro tier with courses, more problems, and AI hints.
Strengths. The free roadmap and YouTube walkthroughs are some of the best free coding prep available. It organizes problems by pattern, which matters more than raw volume when you're short on time.
Limitations. Coding only, plus some system design video content in Pro. No spoken practice, no behavioral coaching.
Best for. Engineers who are rusty on algorithms and need a plan rather than a list of 3,000 problems. Pro is $119/year or $297 lifetime.
4. Hello Interview: best for system design content
What it is. A self-study platform best known for its system design material, with free guides and a Premium tier that adds deeper breakdowns, guided practice for system design, low-level design, and AI coding, a reported-question library, and an AI tutor. See our Hello Interview comparison.
Strengths. The free system design writing is excellent and very practical. Guided practice gives structure to what's otherwise a vague topic. Premium is $47/month, $79/year, or $279 lifetime.
Limitations. It teaches you what to say in a design round. It won't hear you say it, interrupt you mid-sentence, or tell you that your scoping took eight minutes. Its behavioral content is a course, not spoken practice.
Best for. Learning system design. Pair it with spoken practice so you can deliver the design under pressure.
5. interviewing.io: best for a realistic human mock
What it is. Anonymous mock interviews with senior engineers from companies like Google, Meta, and Amazon, covering coding, system design, behavioral, and staff-level and manager loops. It also offers a free AI interviewer for coding and system design. See our interviewing.io comparison.
Strengths. Nothing beats a real senior engineer running a realistic loop and giving you direct feedback. Company-specific interviewers are available.
Limitations. Cost limits frequency. Human mocks start at $179 per session and go up for specific companies, so most people book a few right before the real thing rather than practicing weekly.
Best for. One or two dress rehearsals at the end of prep, once your stories and design approach are already solid.
6. Aced (formerly Exponent) and Pramp: best for courses and free peer mocks
What it is. Exponent has rebranded as Aced. It offers courses for software engineering, system design, and behavioral interviews, plus expert coaching. Pramp, now part of Aced, runs free peer-to-peer mock interviews over video. See our Pramp comparison.
Strengths. Free live practice with another person, good for getting used to thinking out loud while someone watches. The courses are broad.
Limitations. Peer feedback is only as good as your peer, who is also preparing and often calibrated to a different level. Peers tend to be kind, and kind feedback doesn't help much here. Check current pricing for paid plans and coaching.
Best for. Low-cost live reps, especially for coding rounds where a second person makes the practice more realistic.
7. Final Round AI: a copilot, not a coach
What it is. Its headline product is a live Interview Copilot. It listens to your real interview and puts suggested answers on your screen, hidden from screen sharing. It also includes practice interviews. There's a free plan, and Pro starts at about $25/month.
The honest contrast. A copilot is built to help during the interview. A coach is built to make you able to answer without help. For engineers, the problem shows up fast: the follow-up question. "Why that partition key?" "What would you do differently?" A suggested script doesn't survive a second "why," and using real-time help in a live interview can break the employer's interview rules. More on where that line sits: Interview Coach vs. Interview Copilot.
Best for. Candidates who've decided a copilot fits their situation. It isn't a replacement for knowing your own projects cold.
What about ChatGPT?
ChatGPT is a fine question generator and a decent STAR formatter. It's a poor judge of your answers, and the reason is structural: it's built to be agreeable. Paste in a vague migration story and you'll usually get "great example of leadership!" plus a cleaner version of the same vague story.
A hiring manager listening to that answer is asking different questions:
- What did you decide, versus what the team or your lead decided?
- Was this the scope expected at the level you're interviewing for?
- What did you trade off, and would you make the same call again?
- Is the result measured, or just "it went well"?
You also type to ChatGPT, while interviews are spoken. Hearing yourself ramble for four minutes on a two-minute answer is a different lesson from reading a tidy paragraph. Full breakdown: Revarta vs ChatGPT for interview practice →
A 4-6 week prep plan for a mid-level to senior loop
Week 1: Stories first (especially after a layoff).
- Use Story Builder to capture 8-10 stories while the details are fresh: your most complex project, a production incident, a disagreement with a manager or peer, a failure, a time you influenced without authority, and a time you dealt with ambiguity.
- Write down the numbers now: latency, cost, scale, incident counts. You'll forget them by week four.
- Start your coding roadmap (NeetCode 150 or LeetCode) in parallel.
Weeks 2-3: Coding volume plus design content.
- 1-2 hours a day of patterns-based coding practice.
- Work through system design fundamentals on Hello Interview.
- Twice a week, do a spoken Revarta mock focused on behavioral and project deep dive. Fix the "we vs I" problem early.
Weeks 4-5: Spoken pressure.
- Practice explaining designs out loud: scope the problem in two minutes, state the trade-off before you're asked, and answer "what breaks first?"
- For Amazon loops, map at least two stories to each Leadership Principle you're likely to be asked about.
- Daily 30-minute mock sessions mixing behavioral, deep dive, and "tell me about yourself."
Week 6: Dress rehearsal.
- One or two live mocks with a human (interviewing.io or a peer on Pramp).
New grads can flip the ratio: more coding time, fewer but sharper stories built from internships and projects. Non-native English speakers should also read Interviewing in English as a Software Engineer.
Questions worth practicing out loud
Behavioral and deep dive.
- Walk me through the most technically complex project you've worked on.
- Tell me about a time you disagreed with your manager or tech lead.
- Describe a production incident you owned. What changed afterward?
- Tell me about a time you made the wrong technical call.
- Tell me about a time you influenced a decision outside your team.
- Describe a project with unclear requirements. How did you get to clarity?
- Tell me about a time you pushed back on a deadline or scope.
- Why are you leaving, or why did you leave, your last role?
Design communication.
- Before you draw anything, what questions would you ask?
- Why this database and not the alternative?
- What fails first at 10x the traffic?
- What would you cut if you had half the time?
For worked examples, see 20+ STAR Interview Examples by Industry and Scenario.
Bottom line
Use LeetCode or NeetCode for coding. Use Hello Interview to learn system design. Book one human mock on interviewing.io near the end. For the behavioral round, the project deep dive, and explaining your design under pressure, the rounds that decide level, use Revarta.
Weigh the cost against the outcome, not against other apps. Being down-leveled one step at a large tech company costs you the difference in pay every year you stay at that level, and failing a loop usually means waiting months to reapply. $99 for 90 days of spoken practice is small next to either.
Start free with 2 full mock interviews →
Keep reading
- Best AI Interview Coach in 2026: 7 Tools Tested by a Former Hiring Director
- Revarta vs ChatGPT for Interview Practice Compared
- Interview Coach vs. Interview Copilot: The Line Every Job Seeker Should Know
- Amazon Leadership Principles Interview Questions & Answers
- Free "Why Should We Hire You?" Answer Builder
