The difference between a candidate who stumbles through interview prep and one who shows up confident is often tooling. Not because tools replace practice — they don't — but because the right tools eliminate friction and accelerate the feedback loop.
Here's every tool worth knowing, grouped by what it's actually good for.
Problem Practice
LeetCode
The industry standard. Over 3,000 problems with company-specific tags that tell you exactly which problems Amazon or Google tend to ask. The Premium tier (~$35/month) unlocks the company tags and the ability to filter by frequency. If you're targeting a specific company, Premium pays for itself.
Best for: The bulk of your algorithmic practice.
NeetCode
A free companion to LeetCode. NeetCode.io organizes 150 of the most important problems into a roadmap, and each problem has a detailed video walkthrough explaining the pattern. The site also has a 250-problem extended list and a full roadmap covering every data structure and algorithm topic.
Best for: Structured learning and understanding why a solution works, not just what it is.
HackerRank
Used as a screening tool by many companies (especially banks and mid-size tech). The interface mimics what you'll see in take-home assessments. Worth completing their 30 Days of Code if you're not confident with the basics.
Best for: Preparing for company-issued take-home screens.
Codeforces / AtCoder
Competitive programming platforms. The problem difficulty is a notch harder than LeetCode Hard. Useful if you're targeting companies with extremely high algorithmic bars (Jane Street, Citadel, Two Sigma, Google Research).
Best for: Sharpening speed and handling harder-than-typical problems.
Mock Interviews
Pramp (free)
Peer-to-peer mock interviews. You get matched with another engineer preparing for interviews, take turns playing interviewer and candidate. The experience of being watched while coding is a distinct skill from solo LeetCode practice — Pramp is the only free way to practice it at scale.
Best for: Getting comfortable with the social pressure of a live interview.
interviewing.io
Paid mock interviews with engineers currently working at FAANG companies. The feedback is detailed and actionable. Expensive (~$250–300 per session) but the quality gap over peer-to-peer mocks is significant.
Best for: A realistic signal on your current level and high-quality feedback before your actual interviews.
Meetapro
Similar to interviewing.io but often cheaper. Another option for mock interviews with industry professionals.
System Design
"Designing Data-Intensive Applications" (Kleppmann)
Not a website — a book. The single best resource for understanding distributed systems at the depth FAANG system design rounds demand. Dense, but worth it.
System Design Primer (GitHub)
A free, comprehensive overview of every system design topic, with diagrams and worked examples. The GitHub repo has over 200,000 stars for a reason.
ByteByteGo / Alex Xu's books
"System Design Interview" Vol. 1 and 2 are the most accessible entry point. The ByteByteGo newsletter and YouTube channel produce weekly system design case studies.
Best for: Building a working vocabulary for the design round.
Behavioral Prep
A plain text file with STAR stories
Genuinely. Open a Google Doc or Notion, write one STAR-format story for each of Amazon's 16 Leadership Principles (they apply to behavioral rounds everywhere, not just Amazon), and practice them out loud. No tool is more effective for behavioral prep than prepared stories and repetition.
Exponent
A paid platform for PM and engineering interview prep. The behavioral question bank and video walkthroughs are useful if you find it hard to write your own stories.
AI-Powered Tools
ChatGPT / Claude
Both are excellent for explaining solutions. Paste in a problem, ask "explain the sliding window approach to this problem step by step," and you get a tutoring experience that no static editorial can match. Useful for understanding why a pattern applies, not just memorizing what to write.
LeetCodeSaurus
A macOS menu bar app that captures a screenshot of any coding problem and returns a full solution within seconds using Claude, GPT-4o, or Gemini — your choice of provider. Unlike pasting into a chat window, it works as a global hotkey overlay, so it fits into your workflow without switching windows.
It also auto-detects LeetCode problems from your browser via the Accessibility API (no screenshot needed), and has screen share protection built in for when you need it.
Best for: Studying multiple approaches to the same problem, understanding how a solution is structured, and exam scenarios where time is limited.
Download LeetCodeSaurus for free →
The Setup That Actually Works
The engineers who consistently pass FAANG rounds aren't using every tool on this list. They're using a small, consistent stack:
- NeetCode roadmap for structured problem selection
- LeetCode for the actual practice environment and company-tagged problems
- Pramp once a week for live interview simulation
- Notes (Notion, Obsidian, or a text file) for patterns and problems they got wrong
Everything else is supplemental. Tooling is a force multiplier — but only if the underlying practice hours are there.
Preparing for a coding interview? Download LeetCodeSaurus — the macOS assistant that helps you study any coding problem, right from your menu bar. Free to get started.