Node.js / TypeScript Engineer – Developer Tools & Libraries

Symbolica; City Of London; On-site; GBP 80,000 - 100,000; Full time

Job summary

A leading AI research lab in London is seeking a Node.js / TypeScript Engineer to develop and maintain a TypeScript SDK. This onsite role requires strong skills in Python and TypeScript, with a focus on building robust, developer-friendly APIs. You'll collaborate with engineers and researchers to create intuitive integrations. This position offers competitive salary and equity, along with the opportunity to impact real-world AI solutions.

Benefits

Competitive salary and equity package

High-trust, execution-first culture

Ownership of meaningful projects

Qualifications

• Strong proficiency in Python and TypeScript.
• Comfortable owning projects end‑to‑end, from design through release.
• Experience building and maintaining SDKs, libraries, or APIs for external developers.

Responsibilities

• Take ownership of the design, development, and maintenance of our TypeScript SDK.
• Build type-safe, developer-friendly APIs that make our product easy to integrate.
• Optimize performance and reliability, including type-level abstractions and advanced TypeScript features.

Skills

Python

TypeScript

Type-level programming

SDKs

APIs

Effective communication

Job description

About Us

Symbolica is an AI research lab pioneering the application of category theory to enable logical reasoning in machines.

We’re a well-resourced, nimble team of experts on a mission to bridge the gap between theoretical mathematics and cutting‑edge technologies, creating symbolic reasoning models that think like humans – precise, logical, and interpretable. While others focus on scaling data‑hungry neural networks, we’re building AI that understands the structures of thought, not just patterns in data.

Our approach combines rigorous research with fast‑paced, results‑driven execution. We’re reimagining the very foundations of intelligence while simultaneously developing product‑focused machine learning models in a tight feedback loop, where research fuels application.

Founded in 2022, we’ve raised over $30M from leading Silicon Valley investors, including Khosla Ventures, General Catalyst, Abstract Ventures, and Day One Ventures, to push the boundaries of applying formal mathematics and logic to machine learning.

Our vision is to create AI systems that transform industries, empowering machines to solve humanity’s most complex challenges with precision and insight.

About the Role

As a Node.js / TypeScript Engineer, you’ll take ownership of developing and maintaining our SDK — the core interface that enables clients to integrate and use our product effectively. This is a highly technical role, where your work will directly shape the developer experience and ensure that our tools are robust, intuitive, and easy to adopt.

You’ll design, implement, and optimise TypeScript libraries that interact seamlessly with our platform, with a strong focus on type safety, performance, and usability. You’ll also collaborate closely with frontend engineers, researchers, and product leads to ensure our SDK aligns with real‑world developer needs.

📍 This is an onsite role based in our London office (66 City Rd).

Your Focus

• Take ownership of the design, development, and maintenance of our TypeScript SDK.
• Build type-safe, developer-friendly APIs that make our product easy to integrate.
• Collaborate with frontend engineers and researchers to align SDK design with real use cases.
• Write clear documentation and examples to help developers adopt the SDK quickly.
• Optimise performance and reliability, including type-level abstractions and advanced TypeScript features (e.g. Proxy objects, code transformers).
• Establish testing practices and CI pipelines to ensure SDK stability.
• Gather feedback from internal and external developers to iterate on features and improve the developer experience.
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About You

• Strong proficiency in Python and TypeScript.
• Familiarity with advanced type-level programming.
• Experience building and maintaining SDKs, libraries, or APIs for external developers.
• Familiarity with patterns for designing clean, intuitive developer-facing interfaces.
• Passion for writing robust, well-documented, and maintainable code.
• Comfortable owning projects end‑to‑end, from design through release.
• Effective communicator and collaborator, able to work across teams.
• Bonus: exposure to AI/ML projects or interest in building tools for developers in this space.

What We Offer

• Competitive salary and early‑stage equity package
• A high‑trust, execution‑first culture with minimal bureaucracy
• Direct ownership of meaningful projects with real business impact
• A rare opportunity to sit at the interface between deep research and real‑world productisation

We are able to sponsor a Skilled Worker visa for qualified candidates applying to this position. This specific role exceeds the minimum salary threshold set by the UK government for Skilled Worker visa sponsorship. Please note that English language proficiency at B2 level or higher is required for this role.

Symbolica is an equal opportunities employer. We celebrate diversity and are committed to creating an inclusive environment for all employees, regardless of race, gender, age, religion, disability, or sexual orientation.