Here's the plan I'd give a friend, one tool per step: learn the coding patterns on NeetCode, study system design on Hello Interview, practice the interview out loud on DevInterview.ai, which I built, and, only if budget allows, book one session with a human interviewer on interviewing.io before the onsite.
Most plans stop after the first two steps. The interview tests the third: solving out loud while someone watches.
The stack
| Step | Tool | What it does for you | Price as billed |
|---|---|---|---|
| 1. Learn the patterns | NeetCode | The NeetCode 150, a curated list of 150 problems with free video solutions | Free to start; Pro $119/yr (list $199), $297 lifetime (list $599) |
| 2. Study system design | Hello Interview | System design guides built by FAANG hiring managers and staff engineers | Free to start; Premium $59 (1 month), $119 (1 year), $399 lifetime, with a sale running when I checked |
| 3. Practice out loud | DevInterview.ai | Unlimited live voice mock interviews: coding with code that runs, system design on a canvas, behavioral, each with a scored report | First interview free; $19.99/mo, $49.99/qtr, $99.99/yr |
| 4. Super optional: one human read | interviewing.io | An anonymous mock interview with an experienced engineer | From $179 a session |
Step 1: Learn the patterns on NeetCode
Work through the NeetCode 150 by pattern, not at random: arrays and hashing, two pointers, sliding window, stacks, binary search, linked lists, trees, tries, heaps, backtracking, graphs, dynamic programming, greedy, intervals, math and geometry, and bit manipulation. Interviews reward spotting the pattern in the first few minutes, not remembering one specific problem. The list and its video solutions are free. Pro is $119 a year (list $199) or $297 lifetime (list $599) and adds courses, company-tagged problems and AI hints.
Where it falls short: a list trains solving alone, not solving out loud while someone listens.
Step 2: Study system design on Hello Interview
Hello Interview's guides are free to start and, per the site, built by FAANG hiring managers and staff engineers. Read the core concepts, then the worked problems, and say each design out loud as you go. Premium adds full courses and Guided Practice, at list price $59 for 1 month, $119 for 1 year or $399 lifetime, with a sale running when I checked.
Where it falls short: Hello Interview wound down its human mock interviews on May 31, 2026, so nobody pushes back on your design.
Step 3: Practice out loud (this is the one I built)
In a randomized study by researchers at NC State and Microsoft, students who solved a problem on a whiteboard in front of an interviewer performed half as well as students who solved it alone in a private room. Steps 1 and 2 teach the material. This step is the rehearsal for that room.
DevInterview.ai runs live voice mock interviews: a 30-minute coding round in an editor that runs your code, a 45-minute system design round on a canvas, both set to your target company and level, and a 30-minute behavioral round. The interviewer asks follow-ups and is told never to say whether you're right and never to hand you the solution, like a real one. Every interview ends with a scored report and a hire verdict. The first interview is free, then $19.99 a month, $49.99 a quarter or $99.99 a year.
Where it falls short: the interviewer is an AI. You get volume and the same rubric every time, not the judgment of someone who runs real hiring loops. That's step 4.
Step 4, super optional: one human session
If budget allows, book one session with an experienced interviewer on interviewing.io in the final week, from $179 per its FAQ. Treat it as a calibration, not practice. Skipping it is fine.
The 8 weeks
My suggested schedule, for someone working full time with 8 to 10 hours a week:
- Week 1: start the NeetCode 150 with arrays, hashing and two pointers. Take one free mock interview in the round you feel least ready for, to get a baseline.
- Weeks 2 and 3: sliding window, stacks, binary search, linked lists, trees, tries. Start Hello Interview's core concepts. One coding mock a week.
- Weeks 4 and 5: heaps, backtracking, graphs, dynamic programming. Two system design problems a week, out loud. Write 8 to 10 behavioral stories in STAR form. Two mocks a week.
- Weeks 6 and 7: finish the remaining patterns, then go back to whatever your mock reports flagged. A full mock most days.
- Week 8: light review, mocks until the format feels boring, and the optional human session.
If you're short on time or money
- Interview in two weeks or less: go straight to step 3, a full mock most days, and study patterns only where the reports point.
- Budget is zero: the NeetCode 150, Hello Interview's free guides, DevInterview.ai's free first interview, and the 5 free peer mock interviews a month on Aced (formerly Exponent).
Prices checked on each vendor's own site on October 13 and 14, 2026. The full plan, with sources, is on devinterview.ai. If I got something wrong, tell me in the comments and I'll fix it.
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