Staff Engineer (Payroll & Data) at Santander-backed global payments fintech

Company: Jack & Jill
Apply for the Staff Engineer (Payroll & Data) at Santander-backed global payments fintech
Location: London
Job Description:

Job Title

Staff Engineer — Backend (Payroll & Data)

Salary

Not Disclosed

Company Description

Santander-backed global payments fintech with a recent £550M funding round

Job Description

You will architect and build a greenfield, AI-native global payroll engine from the ground up. This role involves designing complex data pipelines that normalize HRIS data into a proprietary calculation engine. You will bridge the gap between HR tech and fintech by connecting automated payroll logic to existing multi-currency payment rails.

Location

London, UK; Madrid, Spain; or Malaga, Spain

Why this role is remarkable

  • Founding-Level Impact: Build an AI-native payroll product from scratch while leveraging a pre-existing infrastructure that processes 1.9M annual payments across 130+ currencies.
  • Massive Backing: Backed by Santander with a fresh £550M raise, providing the stability of a corporate leader with the creative freedom of a greenfield startup environment.
  • Tech-Forward Stack: Direct a team of AI coding agents to 10x your output while owning the architecture in a modern Python, Node.js, and TypeScript environment.

What You Will Do

  • Architect Data Pipelines: Build robust systems to pull, normalize, and transpose data from various HRIS and HCM integrations into a centralized payroll calculator.
  • Develop Calculation Engines: Design jurisdiction-specific logic to handle complex tax, benefits, and deductions, ensuring high-fidelity output for bank files and compliance reports.
  • Orchestrate Workflows: Create end-to-end SaaS workflows from client onboarding and approval routing to the final execution of global payments via existing rails.

The ideal candidate

  • Industry Expertise: Proven experience building payroll engines or payment processing systems at tech-first companies like Deel, Papaya Global, or Remote.
  • Technical Mastery: Staff-level proficiency in Python or Node.js with deep experience in data transformation, dbt, and architecting complex SaaS platforms.
  • Full-Stack Capability: Strong backend focus but possessing enough frontend knowledge (Angular/TS) to direct junior engineers and ensure seamless product delivery.

#J-18808-Ljbffr…

Posted: June 3rd, 2026