Introduction
If you are planning to Hire Next.js developers for your business in 2026, one skill that should be non-negotiable on your checklist is TypeScript expertise. What was once considered an optional add-on for JavaScript developers has now become a core requirement for anyone building serious Next.js applications. Companies that skip this requirement during hiring often pay the price later in the form of buggy codebases, poor maintainability, and slower development cycles. This guide explains why TypeScript has become so critical in the Next.js ecosystem and what to look for when evaluating candidates who claim to know it.
Why TypeScript Has Taken Over the Next.js Ecosystem
A few years ago, many development teams treated TypeScript as a nice-to-have. Developers who preferred the flexibility of plain JavaScript could still get by on most projects without it. That era is effectively over.
Today, the official Next.js documentation is written with TypeScript as the default. Every new feature released by the Next.js team, from Server Components to the App Router to Server Actions, is designed with TypeScript in mind first. The type definitions, the configuration files, and the tooling all assume TypeScript as the baseline.
When you look at production codebases on GitHub, enterprise Next.js projects, and open-source projects built on the framework, TypeScript is present in the overwhelming majority of them. Developers who only know JavaScript are increasingly at a disadvantage when working in modern Next.js environments.
What TypeScript Actually Does for a Next.js Project
To understand why this matters so much for hiring decisions, it helps to understand what TypeScript brings to a Next.js project in practical terms.
- It Catches Errors Before They Reach Production
TypeScript adds static type checking to JavaScript. This means many categories of bugs that would normally only surface at runtime, in front of real users, get caught during development before the code ever ships. For a business running an eCommerce store or a SaaS product, fewer production bugs means less downtime and a better user experience.
- It Makes the Codebase Easier to Maintain
When your Next.js codebase grows beyond a certain size, plain JavaScript becomes difficult to manage. Functions that accept certain types of data, components that expect specific props, API responses with complex shapes, all of these become hard to track without type definitions.
TypeScript acts as living documentation inside the code itself. A developer joining your team six months into the project can look at a typed function and immediately understand what data it expects and what it returns. This reduces onboarding time and lowers the risk of introducing bugs when making changes.
- It Improves the Development Experience
TypeScript enables intelligent code completion, inline documentation, and instant error highlighting inside code editors like VS Code. Developers who work in a well-typed Next.js codebase move faster because their editor gives them accurate suggestions and catches mistakes in real time rather than during testing.
- It Integrates Naturally With the App Router
The Next.js App Router introduced in recent versions relies heavily on TypeScript for defining layouts, page components, metadata, and server-side functions. Type-safe route handling, typed server actions, and typed API responses are all much easier to implement correctly with TypeScript. A developer who does not know TypeScript will struggle to work confidently with the App Router in a production codebase.
The Risks of Hiring a Next.js Developer Without TypeScript Skills
Understanding the benefits of TypeScript is one side of the equation. Equally important is understanding what you risk when you hire a Next.js developer who does not have strong TypeScript skills.
- Technical Debt Accumulates Quickly
A developer who writes Next.js code in plain JavaScript or uses TypeScript incorrectly, such as overusing the "any" type to bypass type checking, will leave behind technical debt that is expensive to clean up later. Future developers on your team will have to deal with untyped code that is hard to refactor safely.
- Bugs Are More Expensive to Fix Later
When type errors are not caught at development time, they show up later as runtime errors in production. Debugging these issues after deployment takes more time and resources than catching them during development. For a growing business, this kind of inefficiency adds up fast.
- Integration With Third-Party Services Becomes Risky
Modern Next.js applications integrate with dozens of third-party services, from payment gateways to analytics platforms to headless CMS providers. Most of these services now provide TypeScript SDKs with detailed type definitions. A developer who cannot work with those type definitions will either skip them entirely or implement integrations incorrectly, leading to fragile connections between your app and the services it depends on.
- Onboarding New Team Members Takes Longer
If your codebase lacks proper TypeScript coverage, every new developer you bring onto the team spends extra time figuring out what the existing code does. This is a hidden cost that compounds as your team grows.
What TypeScript Expertise Actually Looks Like in a Next.js Developer
Not every developer who lists TypeScript on their resume truly understands it. There is a big difference between a developer who knows the basics of TypeScript and one who can use it effectively in a complex Next.js application. Here is what genuine TypeScript expertise looks like.
- They Write Typed Components Correctly
A skilled TypeScript developer knows how to define props interfaces for React components, how to type event handlers, and how to handle optional versus required props clearly. They do not use "any" as a crutch to silence TypeScript errors.
- They Understand Generics
Generics are one of the more powerful features of TypeScript and one of the clearest indicators of deeper understanding. A developer who can write and use generic functions and components demonstrates that their TypeScript knowledge goes beyond the surface level.
- They Know How to Type API Responses
In a Next.js application, data often comes from external APIs. A strong TypeScript developer knows how to define types for API responses and use those types throughout the application so that data is handled safely and predictably at every layer.
- They Use Utility Types Fluently
TypeScript comes with a set of built-in utility types like Partial, Required, Pick, Omit, and Record. A developer who uses these appropriately writes cleaner and more maintainable code than one who defines everything from scratch or avoids them entirely.
- They Configure TypeScript Properly
TypeScript has a configuration file called tsconfig.json that controls how strictly the language checks your code. A developer with real TypeScript experience knows how to configure this file for a Next.js project correctly, including enabling strict mode, which enforces the most thorough type checking.
Interview Questions to Test TypeScript Knowledge Before You Hire
When you are evaluating candidates, asking the right questions makes it easy to separate developers who truly know TypeScript from those who just have it listed on their CV.
Ask them to explain the difference between a type and an interface. This is a foundational TypeScript concept. A developer who cannot clearly explain when to use one over the other likely has shallow TypeScript knowledge.
Ask how they would type a Next.js Server Action. Since Server Actions are a core part of modern Next.js development, a strong candidate should be able to describe how they would ensure type safety across the server and client boundary.
Ask how they handle typing for third-party libraries that do not have TypeScript definitions. This tests practical problem-solving and shows whether the developer can work confidently in real-world scenarios where perfect type definitions are not always available.
Ask them to explain strict mode in TypeScript and why it matters. Developers who understand strict mode and choose to enable it in their projects demonstrate a real commitment to code quality and type safety.
Ask about their approach to typing API responses from an external REST API. This reveals whether they understand how to validate and type external data safely, which is a common and important real-world challenge in Next.js projects.
Red Flags to Watch Out For
When reviewing portfolios or conducting interviews, keep an eye out for warning signs that suggest a developer's TypeScript skills are weaker than claimed.
Codebases where "any" appears frequently are a strong red flag. It usually means the developer was avoiding TypeScript errors rather than solving them properly.
Projects that use TypeScript in file names but have no actual type definitions are another warning sign. Some developers add the .ts or .tsx extension without writing any meaningful typed code.
Developers who cannot explain why TypeScript is useful beyond saying "it catches bugs" likely have not used it deeply enough in a real production environment.
Candidates who push back on TypeScript or suggest that plain JavaScript is just as good for large projects may struggle to fit into a modern Next.js team where TypeScript is the standard.
How to Structure Your Hiring Process Around TypeScript Proficiency
If you want to make TypeScript expertise a genuine requirement rather than just a checkbox, build it into your hiring process from the start.
Include TypeScript in the job description clearly and specifically. Mention that the role requires working in a strictly typed Next.js codebase and that experience with the App Router and typed server-side logic is expected.
Ask for portfolio links and specifically look for TypeScript usage in the repositories provided. Review the code yourself or have a technical lead review it before scheduling an interview.
Include a short take-home task that requires building a small Next.js component or function with proper TypeScript types. This gives you direct evidence of their TypeScript skills rather than relying entirely on self-reported experience.
Make TypeScript a topic in the technical interview stage. Spend at least part of the interview asking type-specific questions to verify the depth of their knowledge.
TypeScript and the Future of Next.js Development
The direction of the Next.js framework makes it clear that TypeScript is not going away. Vercel, the company behind Next.js, has continued to invest in TypeScript-first features with every major release. The framework is becoming more tightly integrated with type-safe tooling across the entire stack, from database queries to API routes to UI components.
In 2026 and beyond, the gap between Next.js developers who know TypeScript well and those who do not will continue to widen. Teams that hire for TypeScript expertise today are building codebases that are easier to maintain, faster to scale, and more resilient to the kind of technical debt that slows companies down as they grow.
Final Thoughts
TypeScript is no longer a bonus skill when you hire Next.js developers. It is a core requirement for anyone working on a production-grade Next.js application in 2026. The benefits it brings in terms of bug prevention, maintainability, developer experience, and long-term codebase health are too significant to ignore.
When you build TypeScript proficiency into your hiring criteria from the beginning, you set your team up to move faster, ship more reliably, and scale your product without the growing pains that come from a poorly typed codebase. The developers who truly know TypeScript are worth finding, and this guide gives you everything you need to identify them.