How to Hire a JavaScript Developer: Skills Checklist and Red Flags

Finding a JavaScript developer who can actually ship clean, maintainable code is harder than it looks. This episode of Development draws on this practical hiring guide for JavaScript roles to walk hiring managers and technical leads through a structured, no-fluff approach — from vetting core language fundamentals all the way through final-round interview tactics. Here's what the episode covers: Non-negotiable JS fundamentals — Why a candidate's grasp of closures, scope, hoisting, and the event loop matters more than any framework badge on their resume. Framework-by-framework breakdown — What to expect from strong React, Next.js, Vue, and Angular developers, including the specific APIs, patterns, and architectural concepts each role demands. Beyond the framework — Key signals to look for around DOM manipulation, testing practices (Jest, Cypress, React Testing Library), version control habits, and genuine full-stack backend experience. Red flags worth taking seriously — Resume padding with framework names the candidate can't contextualize, no tests, zero public work, outdated jQuery-first thinking, and messy repos with undocumented, unstructured code. Soft-signal warning signs — How resistance to code review, poor communication with non-technical stakeholders, and blind spots around security (XSS, CORS, input sanitization) and accessibility can make an otherwise capable developer a costly hire. Interview structure that actually works — A four-stage approach moving from open-ended conversation and technical explanation to real-world debugging challenges and collaboration scenarios — plus why the questions a candidate asks you reveal as much as the ones you ask them. Hiring is one of the highest-leverage decisions a team makes, and this episode gives you a repeatable framework for making it well. More from the show: check out the episode on White Label Software: The Shortcut That Could Make or Break Your Business for more on building and scaling smart technical foundations. DEV