Why Engineering Hiring Is Different
The CHRO who buys HireVue and the CTO who buys Karat are not making the same procurement decision. Engineering hiring has specific characteristics that make general AI interviewers the wrong tool:
Authentic coding signal
Can the candidate actually write code? Competency interview scoring on text responses does not answer this question.
Opportunity cost of engineer interview time
At a fully-loaded $200/hr, 8-16 hours of engineer interview time per hire = $1,600-$3,200 in interview cost alone.
AI-cheating arms race
Async coding assessments face a genuine 2024-2026 AI-cheating problem. Vendor mitigations vary significantly in effectiveness.
Buying committee
CTO or VP Engineering, often with HR Business Partner support. Not CHRO-led. Different risk tolerance and evaluation criteria.
The Three Dominant Models
Model 1: Outsourced Live Interviewing
e.g. KaratPay $250-$400 per interview. Karat engineers conduct live coding interviews on your behalf using Karat-designed problem sets and evaluation rubrics. Your team receives a structured write-up within 24 hours. No engineering time spent interviewing. Best for senior and staff-level roles where the interview quality signal matters most. Not designed for automated async-only screening.
Model 2: Async Coding Assessment
e.g. CodeSignal, HackerRankCandidates take a timed coding challenge asynchronously. AI scores and ranks the results. You review the shortlisted candidates. Scales to high volumes. Most susceptible to AI-cheating; vendor mitigations (process monitoring, proctoring, AI-detection heuristics) reduce but do not eliminate cheating risk.
Model 3: Live Coding with AI Assist
e.g. HackerRank CodePair, CoderPadLive coding environment used during a human-conducted interview. AI assists the interviewer with suggested follow-up questions and real-time code analysis. Preserves the human interview; reduces the preparation and evaluation burden on the interviewer.
Vendor Deep-Dive
| Vendor | Model | Pricing (2026) | Best for | Not a fit when |
|---|---|---|---|---|
| Karat | Outsourced live interviewing | $250-$400 per interview | Senior/staff eng; teams eliminating interviewer time | Automated async only; very low hire volume |
| CodeSignal | Async coding assessment + skills platform | From ~$15,000/yr | Structured assessment at scale; predictive validity | Human-conducted live interviews; very small teams |
| HackerRank | Async + live coding + problem library | From ~$9,000/yr | Broad coding screen; largest problem library | High-stakes roles needing strong anti-cheat; proctoring |
| CoderPad | Live coding IDE + interview recording | From $40/mo (team) | Human interview support; complements Karat or async tools | Fully automated screening; no human interviewer |
The AI-Cheating Problem (2024-2026)
Between 2024 and 2026, the prevalence of AI-assisted cheating on async coding assessments became a significant operational and validity concern. Tools like GitHub Copilot, ChatGPT, and specialised coding-interview AI tools allow candidates to produce code that appears original to an automated grader but was largely generated by AI.
Vendor mitigations as of April 2026:
- CodeSignal:Process monitoring (mouse-leave detection, tab-switch tracking), AI-generated-code detection heuristics, human review flag on suspicious submissions.
- HackerRank:Plagiarism detection, proctoring options (webcam, screen recording), AI-cheating detection; acknowledged to be an arms-race problem in public communications.
- Karat:Live interviews conducted by human engineers; AI cheating is materially harder in a live environment with an experienced interviewer who can probe answers and observe code-writing process. Karat has positioned this as a key product differentiator post-2024.
The honest assessment: AI cheating on async assessments is not fully solvable with current technology. For senior and staff-level roles where a false positive (hiring a poor engineer) is very expensive, the live interview model (Karat or internal with CoderPad) remains the highest-validity option despite its cost.
The Engineering Hiring Cost Model
At 50 engineering hires per year