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Twelve

Software Engineer

Twelve
United Kingdom · Full-time · Mid-Senior

The Opportunity

As an early engineering hire, you will be responsible for designing and building the core architecture of the platform. This role requires a balance of backend systems design and fullstack implementation to ensure features are delivered reliably at scale.


Key Responsibilities:

  • Systems Architecture: Design and implement fault-tolerant, event-driven services using queues, message brokers, and databases.
  • Full Stack Development: Contribute to a React-Native codebase to facilitate end-to-end feature implementation.
  • Technical Excellence: Write secure, high-quality code in TypeScript (Node.js) while maintaining 99.9% system uptime.
  • Security & Compliance: Implement data protection measures that meet payment industry standards, such as PCI DSS and PSD2.
  • Roadmap Strategy: Evaluate technical trade-offs and advocate for architectural improvements that enhance development speed.


About You

Experience: A minimum of 3 years of professional experience as a software engineer.

Technical Proficiency: Strong foundations in distributed systems, including event-based patterns and message brokers.

Modern Stack: Proficiency in TypeScript and Node.js is required. Experience with statically compiled languages (Go, Rust, or Java) is a significant advantage.

Mindset: A pragmatic approach to security and compliance, with the ability to deliver high-quality code in a fast-paced environment.


Working Environment

Location: Based in Hoxton, London.

Format: The team maintains an in-person culture with four office days per week. Wednesdays are optional for remote work to provide flexibility for focused tasks.

Compensation: £60,000 - £80,000 gross annually, depending on experience and qualifications.

Key Skills

Ranked by relevance

typescript pci dss react java rust dss
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Posted
Mar 09, 2026
Type
Full-time
Level
Mid-Senior
Location
London Area
Company
Twelve

Industries

Financial Services

Categories

Information Technology

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