Should you build or buy Technical Skills Assessment & Coding Interviews?
Technical skills assessment software runs live or asynchronous coding tests for hiring: language-specific environments, proctoring, plagiarism and AI-cheating detection, and integration with the applicant tracking system. Engineering hiring teams buy it to standardize how candidates are evaluated across a hiring pipeline rather than improvising each interview.
Purchase an assessment platform sized to hiring volume and invest effort in company-specific questions, rubrics and a clear AI-allowed versus AI-prohibited policy. Building the platform itself only makes sense at Google scale with a strategic reason to own the interview experience.
Build it, buy it, or bridge?
When building makes sense
Building a coding assessment platform is really only proven at one scale: Google runs its own Virtual Interviewing Platform, which provides syntax highlighting and support for major languages like Java, C++, and Python, rather than relying on a third-party vendor tool for live technical interviews. That is a credible build case, but it exists because Google runs an enormous, continuous hiring pipeline where owning the interview experience end to end is worth the sustained engineering investment. Most engineering teams write their own interview exercises regardless of whether they buy a delivery platform, a smaller and much more achievable form of building, since the questions and rubrics are where the actual hiring signal lives. What is genuinely hard to build and maintain yourself is proctoring and AI-cheating detection, an area where vendors are investing continuously because candidates using AI tools during assessments has become a real and growing problem.
When buying makes sense
Buying the delivery platform is the right call for nearly every engineering hiring team, because the platform layer itself, a coding environment, language support, and scoring infrastructure, is generic and confers no hiring advantage on its own. Google's decision to run its own Virtual Interviewing Platform is a scale story specific to one company's hiring volume, not a template most organizations should follow. Vendors like Coderbyte, CodeSignal, HackerEarth, and Karat have kept pace with what has actually gotten harder recently: proctoring and integrity detection, as AI-assisted cheating during assessments has become a real threat that a small internal team would struggle to track continuously. Buy the assessment platform sized to your hiring volume, and spend your own effort where it actually differentiates your hiring: writing company-specific questions, rubrics, and a clear policy on what AI assistance is and is not allowed during the assessment.
The desk read
Build-versus-buy analysis for Technical Skills Assessment & Coding Interviews is being written. In the meantime, the framework that drives every B4 call is on the B4 Index page.
Frequently asked
Does any company actually build its own coding interview platform?
Google does. Its Virtual Interviewing Platform provides syntax highlighting and support for languages like Java, C++, and Python, and it runs candidates through live interviews without a third-party vendor tool. That is a scale decision tied to Google's continuous, high-volume hiring pipeline. Most companies lack the hiring volume to justify copying it.
What is actually hard to build in-house for technical assessments?
Proctoring and AI-cheating detection, not the coding environment itself. As candidates have started using AI tools during assessments, vendors like Karat and Coderbyte have had to invest continuously in integrity detection to keep up, a moving target that is much harder to maintain internally than a static coding interface.
Where should a hiring team actually spend effort if they buy the platform?
On writing company-specific questions and rubrics, and setting a clear policy on what AI assistance is allowed during an assessment. Most engineering teams already write their own interview exercises regardless of which delivery platform they use, and that is where the real hiring signal comes from, not the underlying software.
What are the main technical skills assessment vendors?
Representative vendors include Coderbyte, CodeSignal, HackerEarth, Karat, Codility, HackerRank. They differ mainly in proctoring depth, AI-cheating detection, applicant tracking system integrations, areas that have gotten more important as candidates increasingly use AI tools during assessments. B4 Pro includes the category score and the full vendor list.