How to hire TypeScript developers: a practical guide for U.S. engineering and HR leaders.
Written by Damian WassermanTypeScript became the most used language on GitHub in August 2025, ahead of Python and JavaScript, with more than 2.6 million monthly contributors (GitHub Octoverse 2025). GitHub ties part of that growth to AI-assisted coding: typed code gives both reviewers and coding agents a contract to check against. The consequence for hiring is simple. Almost every JavaScript developer now lists TypeScript, so the résumé keyword no longer separates anyone. This guide covers what does.
What TypeScript developers do
TypeScript is JavaScript with a static type system. Code is checked at build time and compiled to plain JavaScript, so it runs anywhere JavaScript runs: browsers, Node.js, serverless functions, mobile through React Native.
A TypeScript developer's real job is to make a codebase safe to change. On a small project, types are documentation. On a product with several teams, a shared type for an order, a user or an API response is the contract that lets one team change a field without breaking another team's screen. The skill you are hiring for is designing those contracts well, not writing annotations.
One limit matters in interviews: types disappear at runtime. Data from an API, a form, a webhook or an LLM is unknown until something validates it. Strong TypeScript developers know where the compiler stops protecting them and put runtime validation (Zod, Valibot, JSON Schema) at those boundaries.
The four profiles
"TypeScript developer" covers four different hires. Decide which one you need before you write the job description.
| Profile | Owns | Typical stack | Hire when |
|---|---|---|---|
| Frontend TypeScript | UI, components, state, performance, accessibility | React, Next.js, Angular, Vue | The product is UI-heavy or you are building a design system. See our guide to hiring frontend engineers. |
| Backend TypeScript | APIs, data access, queues, integrations | Node.js, NestJS, Express, Fastify, Prisma | You run Node.js services and want types from the database to the API. See hiring backend engineers. |
| Full stack TypeScript | A feature end to end, one type from server to UI | Next.js or React + Node.js, tRPC or GraphQL | A small team ships features end to end. |
| Library / platform | Shared types, SDKs, monorepo tooling, build performance | Project references, Nx or Turborepo, tsconfig design | Several teams share code and type changes keep breaking builds. |
If your backend is Node.js and your frontend is React on MongoDB, you are also looking at MERN stack developers, who are full stack TypeScript or JavaScript developers with a specific data layer.
Seniority you need
- Mid-level developers write correct types for the code in front of them. Good for well-scoped features in a codebase with established patterns.
- Senior developers design types other people build on: discriminated unions for state, generic utilities, API contracts. They can migrate a module to strict mode without stopping feature work. This is the level most teams mean when they say "TypeScript developer."
- Lead or staff engineers set the conventions: strictness level, where validation lives, how shared types are versioned in a monorepo. If this person will also run the team's rituals and reviews, you are hiring a tech lead, not only a senior developer.
Years with TypeScript are a weak signal. Plenty of engineers have used it for five years with strict turned off.
One developer or a team
One senior full stack TypeScript developer can carry a small product or a well-defined migration. Move to a team when you have parallel workstreams (a web app and a public API, say) or when shared types start to need an owner. A common shape for a product squad is two full stack engineers, one frontend specialist and a lead. When the question becomes how services, packages and data should be split across teams, that is architecture work, and it is worth bringing in a software architect before the monorepo sets the structure for you.
Job description essentials
A useful TypeScript job description answers what candidates actually filter on:
- Where the work is: frontend, backend or full stack, and the split in percent.
- The stack: framework and version (React 19, Next.js 16, NestJS 11, Angular), runtime (Node.js, Bun, serverless), database and ORM.
- Strictness: is
stricton today? Is there a migration from JavaScript or to TypeScript 7 planned? - Contracts: how types cross the API (OpenAPI, GraphQL, tRPC) and where runtime validation happens.
- Testing: unit and component (Vitest, Jest, React Testing Library), end to end (Playwright, Cypress).
- AI tooling: which coding assistants the team uses and how generated code is reviewed.
- Team and hours: team size, who they report to, required overlap with U.S. hours.
Skip the laundry list. "React, Angular, Vue, Svelte and SolidJS" tells candidates you have not decided what you need.
Skills, layer by layer
Language core
- Narrowing with
typeof,in, discriminated unions and user-defined type guards. - Generics with constraints, and knowing when a generic is overkill.
unknownversusany, and whyasis a promise the compiler cannot check.- Utility and mapped types (
Partial,Pick,Record,satisfies) used to reduce duplication, not to show off.
Configuration and tooling
- Reading and designing a
tsconfig:strict, module resolution, project references. - typescript-eslint rules that block unsafe patterns.
- Build and check speed in CI. TypeScript 7 moved the compiler to native Go code and reports 8x to 12x faster full builds, which changes what is practical in large monorepos (Microsoft, July 2026).
Boundaries
- Typing API responses from a schema instead of by hand.
- Runtime validation at the edges: requests, env variables, third-party webhooks, LLM output.
- Error handling that is typed, not
catch (e: any).
Framework layer
- Frontend: typed props, state and data fetching in React or Angular; server and client components in Next.js. For a working example of a strict setup, see our Next.js 16 boilerplate built on strict TypeScript.
- Backend: typed controllers, DTOs and database access in NestJS or Express, with Prisma or TypeORM.
Testing
- Tests that catch what types cannot: behavior, edge cases, integration.
AI-assisted work
- Reviewing generated code for silent
any, unnecessary casts and invented APIs. A 2025 study cited by GitHub found 94% of compilation errors in LLM-generated code were type-check failures, which is exactly what a strict setup catches and a loose one hides.
How to interview
A loop that separates senior TypeScript developers from annotated-JavaScript developers:
- Screen (30 min): walk through a codebase they worked on. Ask how types crossed the API and what broke in production anyway.
- Live exercise (60 to 90 min) in your stack: build a small feature with a typed API response, loading and error states, and one test. Frontend candidates in React or Angular, backend candidates in Node.js.
- Code review (30 min): give them a pull request with
ascasts, ananyleak, a missing runtime check and an AI-generated helper that calls a method that does not exist. Ask for review comments. - Team conversation: how they disagree in a review, how they explain a type-driven refactor to a product manager.
Interview in the stack they will use. Strength in one side of the stack does not transfer automatically to the other.
Interview questions
- When would you use
unknowninstead ofany?Best answerunknownforces narrowing before use;anyturns checking off. A strong candidate reaches forunknownat every external boundary and explains how they narrow it. - How would you model a request that can be loading, successful or failed?Best answerA discriminated union with a
statusfield, narrowed in aswitch, with anevercheck in the default branch so a new state fails the build. - Write a function that returns a property of an object, typed so a wrong key fails to compile.Best answer
function get<T, K extends keyof T>(obj: T, key: K): T[K]. Bonus if they explain whyK extends keyof Tmatters. - The API returned a field as
nulland the app crashed, even though the type saidstring. Why, and how do you prevent it?Best answerTypes were written by hand or asserted, not validated. Fix with a schema (Zod or generated from OpenAPI) at the boundary. - How would you move a 200-file JavaScript app to strict TypeScript?Best answerIncremental:
allowJs, convert leaf modules first, enable strict flags per folder, track remainingany, keep shipping features. - What changes for you in TypeScript 7?Best answerStrict on by default, removed options such as
baseUrlandnode10resolution, faster builds. Shows they follow the ecosystem. - An AI assistant produced a helper that compiles. What do you check before merging?Best answerCasts,
any, whether every called API exists, edge cases, and whether the types describe runtime behavior or just silence the compiler.
Red flags
stricthas never been on in any codebase they describe.asor// @ts-ignoreis their default fix for compiler errors.- They cannot name one bug types caught for them, or one that types missed.
- Every example is a tutorial-sized app with no shared types between teams.
- They trust AI-generated code because it compiles.
- Deep type gymnastics in a simple exercise. Clever types that nobody else can maintain are a cost, not a skill.
What it costs
The U.S. median base salary for software developers is $135,980 (BLS, May 2025), before payroll taxes, benefits, equipment and recruiting. Senior TypeScript developers who own shared types or lead a team usually sit above the median.
A senior LatAm TypeScript developer through BEON.tech costs $6,500 to $7,800 per month, all-inclusive ($78,000 to $93,600 per year). TypeScript developers who build AI features are $6,800 to $8,500 per month. Use the LatAm developer cost calculator to compare by country and seniority.
Nearshore in LATAM
Latin America works in U.S. hours, 0 to 4 hours from Eastern time, which matters for a role built around code review. When a shared type changes, the reviewer and the author need to talk the same day. The talent pool is also large and growing: Brazil alone ranked fourth globally with 6.89 million developers on GitHub in 2025 (GitHub Octoverse 2025). Our network includes more than 16,000 TypeScript engineers, most of them senior or above. For a broader view of the region, see our guide to hiring Latin American developers.
Hiring model comparison
| Model | Speed | Vetting done for you | Payroll & compliance | Best for |
|---|---|---|---|---|
| In-house U.S. hire | Slowest | No | You | Roles that must be U.S.-based |
| Freelance marketplace | Fast | Partial, résumé level | Contractor | Short, well-defined tasks |
| Staff augmentation (BEON.tech) | 24–48h shortlist, 2-week start | Yes, live interview + recording | BEON.tech | Ongoing product work on your team |
| Contract-to-hire (BEON.tech) | Same as staff augmentation | Yes | BEON.tech, then you | A migration or role you want to trial first |
| IT recruitment (BEON.tech) | Shortlist first, then your process | Yes | You | Lead roles that set conventions |
The first 90 days
- Week 1: repository access, local setup, a walkthrough of the
tsconfig, lint rules and shared types. First small pull request merged. - Weeks 2 to 4: owns a feature end to end. Reviews other people's pull requests.
- Month 2: proposes one improvement to type safety: a validation boundary, a stricter flag, or removing a class of
any. - Month 3: owns an area of the codebase and its types. If a migration or upgrade was the reason for the hire, it has a plan with milestones.
Hiring with BEON.tech
Tell us the stack, the split between frontend and backend, and how strict your codebase is today. Within 24 to 48 hours you get two or three senior TypeScript developers, each with the recording and scorecard of a live interview in that stack. Most engineers start within two weeks, and 88% are still on the team after year one.