Verdict: study there, rehearse here. Hello Interview has some of the clearest system design courses written, at a one-time $119 a year that never auto-renews, with a sale running when we checked. Their live 1:1 human mocks ended May 31, 2026, and Guided Practice gives per-step feedback, not a conversation; their newer Live Practice adds 35-minute AI system design mocks, counted per plan. DevInterview.AI is the other half: a live voice interviewer that interrupts, follows up, and pushes back for 45 minutes on a design canvas, as often as you want.
Disclosure: we build DevInterview.AI, and this is our site. Every price below was checked against vendor pages on October 19, 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, step-based Guided Practice, and Live Practice AI system design mocks |
| Real-time interviewer | Yes, asks follow-ups as you design, unlimited | AI Live Practice for system design: 35 minutes, 1 to 4 included with Premium, extra $25 each at list price; human mocks ended May 31, 2026 |
| Price | $19.99/mo, $49.99/qtr, $99.99/yr | $59 for 1 month, $119 for 1 year, $399 lifetime, none auto-renew |
| System design | 45 minutes on an interactive canvas, then a design evaluation | Courses, problem breakdowns, per-step AI feedback, 35-minute AI mocks |
| 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; first course free, all of them with a subscription | 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. They have since added Live Practice: you lead a 35-minute system design interview out loud on a shared whiteboard while an AI interviewer asks follow-ups, then get a hire or no-hire call for your target level. Premium includes 1 interview with a month of access, 2 with a year and 4 with lifetime, and extra interviews are $25 each at list price, with a sale running when we checked.
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 $399 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, along with all 20+ courses. Hello Interview's Live Practice covers system design only and counts interviews per plan; here all three formats are unlimited.
Who should pick which
- Learning system design from scratch: Hello Interview's courses, or ours (the first one is free).
- Interview in the next month: DevInterview.AI, several spoken designs a week.
- Both gaps: $119 for their year of content at list price plus $99.99 for our year of unlimited interviews comes to $218.99, less while their sale runs, for a year of both.
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, and it has since added Live Practice AI system design mock interviews.
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. Hello Interview's separate Live Practice is its mock interview format, for system design.
Which is cheaper?
Hello Interview: $119 at list price buys a year of content, one-time, with a sale running when we checked. DevInterview.AI: $99.99 buys a year of unlimited live interviews and every course, and its practice bank is free. They price different things, which is why pairing them works.