What does a TypeScript developer do?
A typescript developer writes code that uses static typing to catch errors before the software runs. This role focuses on building applications with TypeScript, a language that adds type definitions to standard JavaScript. The developer configures the compiler to check code for mistakes and produces clean JavaScript output for browsers or servers. They manage project settings and type declarations to keep large codebases organized and predictable.
- Write application logic in TypeScript files and run the TypeScript compiler to validate the code. The developer uses the compiler to identify type mismatches and syntax errors during the build process. This step ensures that the final JavaScript output functions correctly without runtime type failures. The developer fixes these issues in the source code before merging changes into the main branch.
- Configure project structures using tsconfig.json files to define how the compiler processes the code. The developer sets options for module resolution, target environments, and strict type checking rules. They may use project references to split large applications into smaller, manageable parts. This configuration controls how the build system compiles different sections of the application independently.
- Create and maintain type declaration files to describe the shape of data and external libraries. The developer writes .d.ts files when third-party packages lack built-in type information. They install missing types from the DefinitelyTyped repository using npm packages. This work allows the compiler to understand external APIs and provide accurate autocomplete suggestions.
- Publish type declarations to npm or submit them to the DefinitelyTyped repository for community use. The developer packages these definitions so other engineers can install them as dependencies. This process helps standardize how different projects interact with shared libraries. It reduces the need for every team to write their own type definitions for common tools.
How to hire a TypeScript developer on Upwork
Step 1: Post a job
Define your project needs clearly to attract qualified candidates who understand static typing and compiler configuration. Use the Job Post Generator powered by Umaโข, Upwork's Mindful AI to draft a precise description in seconds. Describe your requirements in a few sentences, and Uma creates a structured post for you. You can write a new post, update a saved draft, or reuse an existing post to save time.
- Specify that the developer must configure projects using tsconfig.json and manage multi-project structures with references.
- Request experience with creating and maintaining .d.ts declaration files for external APIs or internal libraries.
- Ask for proficiency in installing missing type definitions via @types packages from DefinitelyTyped when libraries lack bundled declarations.
Step 2: Evaluate candidates
Look for portfolios that demonstrate clean, type-checked code and proper build artifact generation. Uma can run instant video interviews and build shortlists with side-by-side comparisons to help you assess technical fit quickly.
- Review GitHub repositories for evidence of compiled JavaScript output produced via the TypeScript compiler tsc.
- Check for contributions to DefinitelyTyped or published type declarations on npm to verify community engagement.
- Examine code samples for strict type usage and avoidance of any types, which signals strong discipline in static analysis.
Step 3: Interview your top choices
Discuss specific workflows around type safety and compiler options to gauge depth of knowledge. Schedule and conduct interviews within Upwork Messages, where you receive an immediate transcript and summary after each session.
- Ask how they handle type conflicts when integrating third-party libraries without native TypeScript support.
- Discuss their approach to refactoring legacy JavaScript codebases into TypeScript while maintaining functionality.
- Query their experience with project references and how they structure large-scale applications for maintainability.
Step 4: Agree on scope and begin work
Set clear milestones for delivering type-checked code and updated configuration files. Use Upwork Messages and the contract workroom for communication and project management, plus identity verification, payment protection, hourly tracking, and project funds for security.
- Define deliverables such as compiled build artifacts and updated tsconfig.json files for each milestone.
- Require submission of new .d.ts files for any custom modules or external API integrations they build.
- Establish a process for reviewing pull requests to ensure all new code passes strict type checking before merging.
Upwork is not affiliated with and does not sponsor or endorse any of the tools or services discussed in this article. These tools and services are provided only as potential options, and each reader and company should take the time needed to adequately analyze and determine the tools or services that would best fit their specific needs and situation.
The rates and information provided in this article are based on current data and industry sources available at the time of publication. Freelance rates can vary depending on factors such as experience, location, project scope, and market conditions. Readers are encouraged to conduct their own research to confirm current rates and trends, as this information may change over time.