Verdict: study there, rehearse here. Hello Interview has some of the clearest system design courses written, at a one-time $79 a year that never auto-renews. What it no longer has, at any price, is an interview: their live 1:1 mocks ended May 31, 2026, and their Guided Practice gives per-step feedback, not a conversation. DevInterview.AI is the other half, a live voice interviewer that interrupts, follows up, and pushes back for 45 minutes on a design canvas.
Disclosure: we build DevInterview.AI, and this is our site. Every price below was checked against vendor pages on September 1, 2026, with sources linked at the bottom.
Quick comparison
| DevInterview.AI | Hello Interview | |
|---|---|---|
| Core product | Live voice AI interviews: coding, system design, behavioral | Written courses plus step-based Guided Practice |
| Real-time interviewer | Yes, asks follow-ups as you design | No. Live 1:1 mocks ended May 31, 2026 |
| Price | $24.99/mo, $59.99/qtr, $119.99/yr | $47 for 1 month, $79 for 1 year, $279 lifetime, none auto-renew |
| System design | 45 minutes on an interactive canvas, then a design evaluation | Courses, problem breakdowns, per-step AI feedback |
| Question data | 2,000+ practice questions, company-tagged | 5,000+ questions per their marketing; their live library counts over 12,900 reports |
| Free tier | First interview free, no card; 19 courses and 95 lessons free | Much of the written content is free to read |
What changed at Hello Interview
Until this spring they sold live 1:1 mock interviews and mentorship with real engineers. Their own scheduling page now reads "Programs ended May 31, 2026," with unexpired credits refunded. What continues is the content: courses for system design, low-level design, concurrency and behavioral, a large crowd-sourced database of real reported questions (their marketing says 5,000+; the live library counts over 12,900 reports), an AI tutor, and Guided Practice.
Guided Practice deserves a precise description, because the distinction matters. You work a fixed problem step by step and get instant rubric-based feedback after each step. That teaches the structure of a good design well. It is not a live interviewer: nothing interrupts you mid-thought, asks why you chose that database, or makes you defend a trade-off out loud with the clock running, which is the actual experience of a system design interview.
Where Hello Interview wins
The written material. Their system design courses are among the clearest available, the crowd-reported real-question database is a genuinely valuable dataset, and the pricing is refreshingly honest: one-time payments that never auto-renew, with a $279 lifetime option. If your gap is knowledge, start there, and we say the same in our own system design tools comparison.
Where DevInterview.AI wins
The rehearsal. Once you know what a good design looks like, the remaining skill is producing one out loud under pressure, and that only comes from doing it. DevInterview.AI runs the interview itself: 45 minutes of live voice on a design canvas, an interviewer that probes your choices as you make them, then a scored design evaluation with a hire verdict. Coding and behavioral interviews are included in the same subscription, and the free tier covers 19 courses and 95 lessons, so the study layer costs nothing here.
Who should pick which
- Learning system design from scratch: Hello Interview's courses, or our free ones.
- Interview in the next month: DevInterview.AI, several spoken designs a week.
- Both gaps and $10 to spare: $79 for their year of content plus $119.99 for our year of unlimited interviews is still less than a single human mock session.
FAQ
Did Hello Interview shut down?
No. Only the live 1:1 mock interview and mentorship programs ended, on May 31, 2026. Courses, the question database, the AI tutor, and Guided Practice continue.
Is Guided Practice the same as a mock interview?
No. Guided Practice walks you through a problem step by step with instant feedback per step. A mock interview is a live conversation where the interviewer interrupts and challenges you in real time. The first teaches structure; the second trains delivery.
Which is cheaper?
Hello Interview: $79 buys a year of content, one-time. DevInterview.AI: $119.99 buys a year of unlimited live interviews, and its courses and practice bank are free. They price different things, which is why pairing them works.