Quick Answer
EngineerSpeak is an AI mock interview tool for software developers, data scientists and ML engineers: you answer technical questions by voice, the AI asks follow-ups and scores correctness and completeness, with optional English feedback. It offers one free session with no card. Mockly is live 1:1 coaching with two UK data engineers who run coding, system design and behavioural rounds and correct your English, at $50 a session with a free 30-minute trial. Use EngineerSpeak for unlimited technical Q&A reps; use Mockly to rehearse full rounds with a person.
⚡ Quick Stats
What EngineerSpeak Is
These facts come from engineerspeak.com, checked on 1 November 2026.
- AI mock interviews for software developers, data scientists and machine learning engineers.
- Tracks cover software development, data science, machine learning, and backend tracks for Java, Node.js, Python, PHP and C#. You pick Junior, Middle or Senior.
- Two modes: a learning mode where you answer single questions and get immediate feedback, and an AI mock interview mode with questions matched to your level.
- You answer by voice. The AI asks follow-up questions about constraints, implementation details, architecture and trade-offs.
- Feedback covers correctness, completeness, missing concepts, depth and trade-offs. Optional English feedback covers grammar, clarity, professional vocabulary and natural phrasing.
- The site language and interview language can be set separately.
- One free session, no credit card. Runs in the browser. Audio is deleted after transcription.
Insight
EngineerSpeak's homepage did not show paid plan prices when we checked, so we do not quote one.
What Each One Checks
| EngineerSpeak | Mockly | |
|---|---|---|
| Who asks the questions | AI | A practising data engineer (Tom or Sophie) |
| Question types | Technical knowledge questions by role and level, with follow-ups | Full rounds: coding, system design (on Excalidraw), behavioural and leadership |
| Technical feedback | Correctness, completeness, missing concepts, trade-offs | Whether the approach and explanation would pass, from an engineer |
| English feedback | Optional: grammar, clarity, vocabulary, phrasing | The main focus: the exact phrases that sounded unsure, and what to say instead |
| Behavioural / STAR answers | Not described on the site | Yes, including Amazon-style leadership questions |
| Availability | Any time, in the browser | Booked 60-minute sessions on Google Meet |
| Price | 1 free session; paid prices not shown | $50 a session; packs from $42.50 a session; free 30-minute trial |
Where an AI Technical Interviewer Helps
Technical knowledge questions are a numbers game. If you need to explain the difference between a process and a thread, how an index works or when to use a message queue, you get better by answering many of them out loud. An AI interviewer that asks follow-ups and never gets tired is a good fit for that volume, and EngineerSpeak's role and level tracks keep the questions relevant.
Speaking your answers matters even more if English is not your first language. Our guide to explaining code out loud in English has phrases you can practise in those sessions.
Where a Human Coach Helps
A real interview loop is more than a set of knowledge questions. A system design round needs you to steer a 45-minute conversation. A behavioural round needs a story with a clear result. An interviewer also reacts to how you sound: hedging, over-apologising or a long silence while you translate in your head.
In a Mockly session, the coach runs the round as an interviewer would, then stops and goes through it with you: the sentences that made your answer sound junior, the order that would have been clearer, and a second attempt in the same session. You leave with a drill list for the next week.
EngineerSpeak and Mockly: Pros and Cons
EngineerSpeak
PROS: unlimited technical Q&A practice by voice; role and level tracks; AI follow-ups on trade-offs; optional English feedback; one free session with no card; works in the browser. CONS: AI, not a person; built around knowledge questions rather than full rounds; behavioural interviews not described; paid prices not shown on the homepage.
Mockly
PROS: a human engineer runs complete rounds, including system design and behavioural; feedback on both structure and English; second attempt in the session; free 30-minute trial. CONS: booked sessions, not unlimited practice; $50 a session costs more per hour than an app; two coaches, so fewer slots.
Verdict
They work well together. Use EngineerSpeak for daily technical question reps; book Mockly sessions for the rounds you are most worried about, a week or two before the loop.
For other AI tools, see Huru AI review, Mockly vs Final Round AI and Best mock interview platforms for non-native speakers.
Talk to an engineer-coach first
Book a free 30-minute Google Meet with Sophie or Tom. No card, no subscription. You practise a short interview-style prompt in English and leave with a plan for what to work on next.
Book a Free Trial →