Hire TypeScript developers who let the compiler catch bugs before your users do

• You are migrating a large JavaScript codebase to TypeScript and need someone who can turn on strict incrementally with allowJs, type the risky modules first, and keep shipping features instead of freezing the roadmap for a full rewrite.
• Your frontend and Node backend keep drifting out of sync, and you want shared types so an API change breaks the build at compile time, not in production, using tRPC, generated OpenAPI or GraphQL types, or a shared package.
• The codebase technically compiles, but it is full of any, as casts, and @ts-ignore, so the compiler passes while production still throws 'undefined is not a function.' You need someone to tighten the types until they actually mean something.
• You are standing up a TypeScript monorepo with pnpm workspaces or Turborepo and need project references configured so shared packages type-check and build fast without circular reference and slow-compile headaches.

Every engineer we put forward is screened by a senior Grape5 engineer before you meet them. For TypeScript developers, we look specifically at:

• Whether they reach for unknown, discriminated unions, and type narrowing instead of any and as casts, and can explain that an as assertion tells the compiler to stop checking rather than proving anything is true.
• That they can author generics, not just consume them: writing a correctly typed generic utility with constraints, and knowing when to let inference work versus when to add explicit annotations.
• Runtime validation at the boundary. TypeScript types are erased at build time, so we check they parse untrusted input (request bodies, API responses, env vars) with Zod or io-ts rather than trusting a type that does not exist at runtime.
• tsconfig fluency: strict, noUncheckedIndexedAccess, exactOptionalPropertyTypes, getting module and moduleResolution right for ESM versus CommonJS, and using project references to keep monorepo builds fast.
• How they handle third-party and missing types: writing or augmenting .d.ts declarations, using module augmentation, and dealing with wrong or absent @types packages instead of casting the problem away to any.