To practice coding interviews without a partner, replace the two things a partner gives you: follow-up questions, and the pressure of thinking out loud for an audience. An AI interviewer that talks gives you both on demand: DevInterview.AI runs unlimited live voice mock interviews with code that runs and a scored report, for $19.99 a month, with the first interview free. With no budget, a self-mock routine gets you part of the way: an unseen problem, a timer, your own voice and a recording.
Disclosure: we build DevInterview.AI, one of the options below. Prices come from each vendor's own pages, checked between October 8 and October 14, 2026, with sources at the bottom.
What a partner actually gives you
A good practice partner does three things. They pick a problem you have not seen. They interrupt with follow-ups: what is the complexity, what happens on an empty input, can you do better. And they watch, which is what makes it feel like the real thing. Alone, the first is easy, the second is hard, and the third needs someone, or something, on the other side.
Your options
| Option | Asks follow-ups | Spoken | Feedback | Price as billed |
|---|---|---|---|---|
| Self-mock routine | No | You talk to yourself | You grade yourself | Free |
| DevInterview.AI | Yes | Live voice interviewer | Scored report with a hire verdict | First interview free; $19.99/mo, $49.99/qtr, $99.99/yr |
| interviewing.io's AI Interviewer | Not stated | Not stated | Feedback at the end | Free |
| ChatGPT voice mode | Not stated | Yes | Not stated | Free with daily limits; Plus $20/mo |
| Peer mocks on Aced (formerly Exponent) | Yes, from another candidate | Live | Notes from your partner, using Aced's rubrics | Free, 5 a month |
1. The self-mock routine (free)
- Pick a problem you have not seen, at your level: an untouched one from the NeetCode 150, or a list tagged to your target company.
- Set a timer for 30 to 45 minutes and do not pause it.
- Talk the whole time: restate the problem, walk an example, state the brute force and its complexity, improve it, code it, and test it by hand.
- Record yourself. Listen back once and count the silences.
- Grade four things: did you clarify the problem, state the complexity, test your code, and keep talking.
Its limit: nobody pushes back, so you never practice the follow-up question, which is where many interviews are decided.
2. An AI interviewer that talks: DevInterview.AI
DevInterview.AI is the closest thing to a partner on demand. It runs a 30-minute coding round in an editor that runs your code, in any of 7 languages, set to your target company and level. The interviewer talks, asks follow-ups, and is instructed never to tell you whether you are right and never to hand you the solution, so you practice working through being stuck. Each interview ends with a scored report and a hire verdict. The same plan covers a 45-minute system design round on a canvas and a 30-minute behavioral round.
Pricing: the first interview is free, no card. Unlimited interviews are $19.99 a month, $49.99 a quarter or $99.99 a year.
Where it falls short: it is an AI, not a person who runs real hiring loops, and it will not give you the nerves of a stranger watching. Pair it with one human session before the onsite if you can.
3. interviewing.io's free AI Interviewer
Per its site, interviewing.io's AI Interviewer "conducts coding and system design interviews, in the style of a FAANG mock interview", with feedback at the end, and it is free. The site does not say whether it speaks or runs your code, so try one session and see whether it fits how you practice.
4. ChatGPT voice mode
A general voice assistant you prompt yourself: tell it to act as an interviewer, give it a problem, and ask it to push back. It is free with daily limits, and Plus is $20 a month. OpenAI does not describe an interview mode or scoring, so the structure and the pushback are whatever you prompt for.
5. Peer mocks, if a stranger counts
If a stranger counts as a partner, Aced (formerly Exponent) matches you with another candidate and you interview each other. Free accounts get 5 peer mock interviews a month, and after each session you and your partner trade notes using realistic rubrics, in Aced's words. Its AI feedback is for paid members and covers behavioral, product management, system design, and data science and ML interviews. Every session needs scheduling, and part of it goes to interviewing your partner.
System design without a partner
System design is harder alone, because the interviewer's questions steer the design. DevInterview.AI's 45-minute system design round runs on a canvas and is set to your target company and level. Hello Interview's Guided Practice "walks you through the steps of an interview with personalized feedback"; it comes with Premium, at list price $59 for 1 month, $119 for 1 year or $399 lifetime, with a sale running when we checked. Our system design practice tools comparison covers the rest.
Where this fits in a full plan
Practicing alone is step 3 of our 8-week study plan: learn the patterns on NeetCode, study system design on Hello Interview, practice out loud on DevInterview.AI, and optionally book one session with a human interviewer.
Which should you try first?
- You want the closest thing to a partner: DevInterview.AI's free interview, set to your target company and level. Every rating we have ever received is public on our reviews page.
- Your budget is zero: the self-mock routine above, plus interviewing.io's free AI Interviewer.
- You want a human, any human: peer mocks on Aced (formerly Exponent), 5 free a month.
How we evaluated
We checked each option on the vendor's own site between October 8 and October 14, 2026, and recorded only what it states; where a site does not say something, such as whether an AI interviewer speaks, we say so rather than guess. The self-mock routine is our view. We build DevInterview.AI, so we put the free options in the same table.
FAQ
How do I practice coding interviews without a partner?
Use an AI interviewer that talks back, or run a self-mock: an unseen problem, a 30 to 45 minute timer, talking out loud the whole time, recorded so you can review it. DevInterview.AI runs live voice mock interviews with follow-up questions and a scored report, for $19.99 a month, with the first interview free.
Can I do a mock coding interview with AI?
Yes. DevInterview.AI runs live voice mock interviews for coding, system design and behavioral rounds, with an editor that runs your code and a scored report with a hire verdict. interviewing.io also offers a free AI Interviewer for coding and system design, and its site does not say whether it speaks.
Is practicing alone as good as a mock interview with a person?
In our view, for volume, practicing alone with an AI interviewer is better per dollar, because the skill comes from many repetitions. For the nerves of a person watching, a human is still the real thing, so add peer mocks or one paid session near the onsite.
How do I practice system design interviews by myself?
Say each design out loud against a timer, then get pushback from an interviewer that asks questions: DevInterview.AI runs 45-minute system design interviews on a canvas, set to your target company and level. Hello Interview's Guided Practice, part of its Premium plan, walks you through the steps of an interview with personalized feedback.