Senior Full Stack Engineer (Freelance)

Company Description

WORTH is building an AI-native Wealth OS.

We turn fragmented, messy, real-world financial data into structured, validated, and reliable intelligence. Our systems are designed to handle partial inputs, ambiguity, and correction loops without breaking trust or usability.

We are operating in stealth and moving from a working prototype to a production-grade platform.

Please read before applying

To be respectful of everyone's time, we will only review applications that meet all the requirements below.

If this role is not a strong match, please do not apply.

Role Description

This is a senior freelance / contract role for a Full-Stack Engineer based in the UK, EU, or Israel.

You will own the implementation of end-to-end ingestion and validation flows, spanning frontend state management, backend APIs, and data models.

This is a hands-on, ownership-heavy role with minimal hand-holding.

You will work directly with the founders to convert non-deterministic inputs into deterministic system behaviour and ship code that is reliable in production.

This role is system- and data-driven, not UI- or design-led.

Required (please apply only if all apply)

• 5+ years of professional software engineering experience
• Advanced React + TypeScript, including state-heavy and form-heavy workflows
• Node.js + TypeScript backend experience (REST APIs)
• Strong relational data modelling (Postgres or equivalent)
• Experience shipping production systems end-to-end
• Comfort working with ambiguity, edge cases, and incomplete data
• Ability to consume AI-generated outputs and enforce validation, correctness, and determinism

Strong Advantage

• Experience with AI-integrated products (LLMs, OCR, AI-assisted ingestion)
• Background in fintech, wealth, accounting, or other high-integrity data domains
• Ownership of core systems in startup environments

Do NOT apply if

• You are a student, recent graduate, or career switcher
• You are primarily a UI / design-focused frontend engineer
• Your experience is mostly no-code, low-code, or CMS-based
• You are looking for visa sponsorship
• You are applying to many roles with the same CV