> Markdown version of [/jobs/ext/2881403-typescript-engineer-codebase-expert](https://www.wearedevelopers.com/jobs/ext/2881403-typescript-engineer-codebase-expert). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md).

---

# TypeScript Engineer - Codebase Expert

- **Company:** Mercor, Inc.
- **Location:** New York, NY, United States (Remote available)
- **Experience:** Experienced
- **Salary:** $145,600.0 - $166,400.0
- **Contract:** Permanent contract
- **Skills:** Artificial Intelligence, Automation of Tests, Command-Line Interface, Compilers, Programming Tools, Node.Js, Software Engineering, TypeScript, State Machines, Git, Containerization, Codebase, Graphql
- **Published:** September 13, 2026
- **Apply:** https://www.careerjet.com/jobad/usa6e04423d2f627dde778c2d44a19355e

## About the Role

* 3+ years of professional software engineering experience, with substantial production TypeScript.
 * Demonstrated ability to navigate a large, unfamiliar TypeScript monorepo and explain how it behaves at runtime.
 * Fluency in the advanced type system, module resolution, bundlers and transpilers, and the Node and browser runtimes.
 * Precise written English: the questions and rubrics you write are the product.
 * Comfortable with git at commit level, containerized environments, and command-line tooling.

Preferred

 * Experience with developer tooling, compilers, test frameworks, GraphQL servers, or state machines.

Compensation & Legal

 * Payment is per approved task; every task is reviewed by a second engineer and a super reviewer before acceptance.

## Description

* Select tasks from a pre-validated pool of TypeScript repositories, each pinned to a specific git commit and arriving with an engineering question, positive and negative rubrics, foils, and a golden solution.
 * Explore the repository until you genuinely understand the subsystem in question, including the relevant PR or issue history.
 * Rewrite the task's question so it defeats frontier coding agents while remaining well-defined and fairly answerable.
 * Adjust rubrics and foils to reward correct reasoning and reject plausible-but-wrong answers.
 * Run the full validation loop in Studio - Check, Golden, Run, Analyze - and iterate until every stage passes.
 * Document your work in the task README and submit for expert review, addressing reviewer feedback on returned tasks., PS: Our team reviews applications daily. Please complete your AI interview and application steps to be considered for this opportunity.


## Related Videos

- [How a Small Team Shrank a Microsoft Monorepo by 94%](https://www.wearedevelopers.com/videos/1236-how-a-small-team-shrank-a-microsoft-monorepo-by-94)
- [Stop using Node.js like in 2020! What changed and what you can do today with Node.js](https://www.wearedevelopers.com/videos/100011-stop-using-node-js-like-in-2020-what-changed-and-what-you-can-do-today-with-node-js)
- [Putting the Graph In GraphQL With The Neo4j GraphQL Library](https://www.wearedevelopers.com/videos/257-putting-the-graph-in-graphql-with-the-neo4j-graphql-library)
- [End-to-End TypeScript: Completing the Modern Development Stack](https://www.wearedevelopers.com/videos/1580-end-to-end-typescript-completing-the-modern-development-stack)
- [Stop Using Node.js Like It’s 2020! - Alfonso Graziano](https://www.wearedevelopers.com/videos/1863-stop-using-node-js-like-it-s-2020-alfonso-graziano)
- [Git for Code Reviews](https://www.wearedevelopers.com/videos/429-git-for-code-reviews)

## Related Articles

- [What is TypeScript?](https://www.wearedevelopers.com/magazine/47-what-is-typescript)
- [Exploring TypeScript: Benefits for Large-Scale JavaScript Projects](https://www.wearedevelopers.com/magazine/554-exploring-typescript-benefits-for-large-scale-javascript-projects)
- [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers)
- [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline)
- [Dev Digest 159: AI Pipelines, 10x Faster TypeScript, How to Interview](https://www.wearedevelopers.com/magazine/563-dev-digest-159-ai-pipelines-10x-faster-typescript-how-to-interview)
- [Dev Digest 136 - No JS(on) of mine](https://www.wearedevelopers.com/magazine/482-dev-digest-136-no-js-on-of-mine)