沒有面試練習夥伴，如何練習編碼面試？5 種選擇及價格核對

I built DevInterview.ai, one of the options below, so I'm biased. I put the free options in the same table.

A practice partner gives you three things: a problem you haven't seen, follow-up questions (what's the complexity, what about an empty input, can you do better), and someone watching. Alone, the first is easy. The other two need someone, or something, on the other side.

Your options

1. The self-mock routine (free)

1. Pick a problem you haven't seen, at your level, like an untouched one from the NeetCode 150.
2. Set a timer for 30 to 45 minutes and don't pause it.
3. Talk the whole time: restate the problem, walk an example, state the brute force and its complexity, improve it, code it, test it by hand.
4. Record yourself. Listen back once and count the silences.
5. 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 a lot of interviews are decided.

2. An AI interviewer that talks: DevInterview.ai

This is the one I built. 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 told never to say whether you're right and never to hand you the solution. 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. First interview free, then $19.99 a month.

Where it falls short: it's an AI, not a person who runs real hiring loops, and it won't give you the nerves of a stranger watching.

3. interviewing.io's free AI Interviewer

Per its site, it runs coding and system design interviews in the style of a FAANG mock, with feedback at the end, for free. The site doesn't say whether it speaks or runs your code, so try a session and see.

4. ChatGPT voice mode

Tell it to act as an interviewer, give it a problem, and ask it to push back. Free with daily limits, Plus is $20 a month. OpenAI doesn't describe an interview mode or scoring, so the structure is whatever you prompt for.

5. Peer mocks, if a stranger counts

Aced (formerly Exponent) matches you with another candidate and you interview each other. Free accounts get 5 a month, and afterwards you trade notes using realistic rubrics, in Aced's words. Every session needs scheduling.

System design without a partner

Harder alone, because the interviewer's questions steer the design. DevInterview.ai's 45-minute system design round runs on a canvas and asks those questions. 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 I checked.

Where this fits

Practicing alone is step 3 of the plan I'd give a friend: learn the patterns on NeetCode, study system design on Hello Interview, practice out loud on DevInterview.ai, and, super optional, one human session on interviewing.io. The full 8-week version is here.

Checked on each vendor's own site between October 8 and October 14, 2026. The full article, with sources, is on devinterview.ai.