The internet is full of lists of 'free interview prep resources' that are either two years out of date or just links to the same handful of sites everyone already knows. This guide is different. We've audited over 60 tools and platforms, tested each one against real interview scenarios across software engineering, product management, data science, and finance roles, and only included tools that genuinely move the needle. Each entry notes what it covers well and where it stops being useful — so you can build a stack rather than get stuck on one platform.
How to use this guide
Start with your target role and company. Scroll to the relevant section, pick 2–3 tools from each category, and build a 4-week prep plan. Trying to use every tool on this list is a common mistake — depth beats breadth.
1. Question Banks — Free Sources with Real Questions
Question banks are the foundation of any prep plan. The best ones are sourced from real candidate reports, updated frequently, and organised by company and role — not just topic.
| Resource | Best For | Coverage | Updated? |
|---|---|---|---|
| Glassdoor Interviews | All roles | 5M+ reported questions by company/role | Continuously (user-submitted) |
| Blind Interview Questions | Tech roles (SWE, PM, DS) | Company-specific, often very recent | Continuously (user-submitted) |
| LeetCode Discuss | SWE coding rounds | Exhaustive LC problem + company tag | Continuously |
| Interview Intel (Free) | All roles — structured by company loop | 50+ companies, all round types | Continuously (AI + human verified) |
| IGotAnOffer | PM and consulting | High-quality frameworks + real Q&As | Quarterly |
| Hackerrank Prepare | SWE coding | Structured tracks by topic | Annually |
| Exponent | PM and SWE (freemium) | Strong PM content, limited free tier | Quarterly |
What most question banks miss
Most question banks give you the questions but not the evaluation rubric. Interviewers score against a specific framework — LP alignment at Amazon, the 'two-by-two' for PM case questions at Google, the 'so what' test for DS take-homes. Interview Intel includes the rubric alongside the question.
2. Coding Interview Prep — Free Platforms
For software engineering roles, coding rounds are typically the highest-stakes component. These platforms offer meaningful free access.
| Platform | Free Tier | Best For | Weakness |
|---|---|---|---|
| LeetCode | ~70% of problems free | Algorithm and data structure pattern practice | Doesn't simulate timed interview conditions well |
| HackerRank | All challenges free | Structured tracks by language and topic | Problems are easier than most FAANG rounds |
| NeetCode.io | Full roadmap free | Curated LC patterns with video solutions | No practice environment — redirects to LC |
| AlgoExpert (trial) | 10 free problems | High-quality explanations | Very limited without subscription |
| Codeforces | Fully free | Competitive programming, advanced problems | Not interview-calibrated |
| Pramp | Free peer mock interviews | Live coding practice with a real peer | Match quality is variable |
3. System Design — Free Study Resources
System design is the round most candidates underprepare for because there's no 'correct' answer — it's evaluated on structure, trade-off reasoning, and breadth. These free resources are the highest quality available without a subscription.
- System Design Primer (GitHub) — 200k+ stars, covers all major components with diagrams. Best starting point for SWE roles.
- ByteByteGo newsletter (free tier) — Alex Xu's weekly visual explainers. Excellent for distributed systems.
- Gaurav Sen on YouTube — free, high-quality video walkthroughs of real system design problems.
- InfoQ articles — engineering blog posts from real teams at Google, Netflix, Stripe on how they built and scaled systems.
- Engineering blogs directly — Netflix Tech Blog, Stripe Blog, Airbnb Engineering, Uber Engineering are free and show real design decisions.
4. Behavioural Interview Prep — Free Resources
Behavioural rounds are frequently treated as an afterthought and just as frequently cause rejections at the final stage. The best free resources focus on structure and story selection, not just lists of potential questions.
| Resource | Format | Best For |
|---|---|---|
| Interview Intel AI coach (free tier) | AI mock interview with feedback | STAR structure, LP alignment, narrative coaching |
| Amazon's LP page (amazon.jobs) | Official documentation | Understanding exactly what Amazon is evaluating |
| Google re:Work | Research-based guides | Structured interview methodology from Google HR |
| Big Interview (freemium) | Video interview practice | On-camera presence and delivery |
| LinkedIn Interview Prep | Question library + AI feedback | General practice across roles — surface level |
5. Salary and Compensation Data — Free Sources
Compensation data is only useful if it's role-specific, level-specific, and current. Most free sources fail on at least one of these dimensions. Here's where the data is actually reliable.
| Source | Data Type | Granularity | Recency |
|---|---|---|---|
| Levels.fyi | Total comp by company/level/location | Very high (L4/L5/L6 etc.) | Excellent — user-submitted continuously |
| Glassdoor Salaries | Base salary by company and title | Medium — titles not standardised | Good |
| Blind Salary Sharing | TC by company and level (anonymous) | High for tech companies | Good |
| H1B Salary Database (h1bdata.info) | Exact filed salaries by employer/role | Very high — legally required filings | Annual (fiscal year lag) |
| Bureau of Labor Statistics OES | National and regional median wages | Low — OES codes too broad | Annual |
| LinkedIn Salary Insights (Premium) | Role benchmarks with filters | High — requires Premium ($) | Good |
Pro tip: Use Levels.fyi + H1B data together
Levels.fyi gives you user-reported total comp including equity. H1B data gives you the base salary employers are legally obligated to pay — which is a floor, not a ceiling, but a useful anchor. Cross-referencing both gives you a strong range to anchor your negotiation.
6. Resume Resources — Free Tools
| Tool | What It Does | Free? | Best For |
|---|---|---|---|
| Resume Worded | ATS score + keyword gap analysis | Limited free (3 scans) | Quick ATS check |
| Jobscan | JD-to-resume keyword match | Limited free | Tailoring resume to a specific JD |
| Interview Intel Resume Lab | Full ATS + narrative + AI rewrite | 10 scans free/month | Deep resume audit with suggestions |
| Google Docs Resume Templates | Clean, ATS-safe templates | Fully free | Getting formatting right |
| Hemingway Editor | Readability and clarity check | Fully free | Tightening bullet prose |
| Grammarly (free tier) | Grammar and tone | Free (premium for style) | Final polish |
7. Company Research — Free Sources
- Glassdoor Company Reviews — culture, management, interview process reports from real employees and candidates.
- LinkedIn Company Page — recent news, employee growth trends, team structure.
- Crunchbase / PitchBook (free tier) — funding history, investors, recent rounds. Essential for startup interviews.
- SEC EDGAR (public companies) — 10-K annual reports and 10-Q quarterly filings. Read the Risk Factors section for any public company before your interview.
- Earnings call transcripts (Seeking Alpha free tier) — hear what management is saying publicly about company priorities.
- Interview Intel Company Prep — structured guides to each company's specific interview format, culture signals, and recent strategic context.
8. Community Resources — Where to Get Real Advice
- r/cscareerquestions — large, active community. Strong signal-to-noise for SWE roles at mid-to-large companies.
- r/leetcode — coding-focused discussions. Useful for recent interview reports.
- Blind — anonymous, often brutally honest. Finance, tech, and consulting communities are particularly active.
- Discord servers — many role-specific communities (Exponent PM Discord, SWE Discord servers) offer mock interview matching.
- Interviewing.io — peer mock interviews with anonymous engineers from top companies. Free to try, paid for on-demand.
Bottom Line: Build a Stack, Not a Collection
The candidates who perform best in competitive loops don't use the most tools — they use the right combination of tools and go deep. A recommended stack for most roles: one question bank (Interview Intel or Glassdoor), one coding platform (LeetCode with NeetCode roadmap), one mock interview tool (Pramp or Interview Intel AI coach), and one compensation reference (Levels.fyi). Add company-specific engineering blogs and the SEC/earnings calls for the company you're targeting. That's your full free prep toolkit.