Software Developer at Haystack, London, £500-£600 per day

Senior Software Developer | £500 - £600

We're working with a global energy transformation leader with a 150-year legacy of innovation on this exciting opportunity. We are looking for a heavy-hitting Senior Developer who can bridge the gap between complex finance logic and high-performance Ruby on Rails engineering.

This is a high-impact, Outside IR35 role where you will drive the decarbonisation agenda by streamlining digital solutions for Finance, Accounting, and FP&A teams. You will be the technical gatekeeper, shaping pre-development solutions and ensuring enterprise-grade code quality within a fast-moving, green-tech environment.

The Role

• Lead the design and development of pragmatic, sustainable technical solutions using Ruby on Rails to support complex finance data flows.
• Act as a technical solution shaper, engaging with Accounting and Controlling stakeholders to translate business needs into actionable technical requirements.
• Architect and review integrations across the application landscape, ensuring alignment with modern CI/CD pipelines and cloud platform standards.
• Identify inefficiencies in target-state finance processes and implement automated digital solutions to reduce manual effort and risk.
• Collaborate with cross-functional onshore and offshore teams to ensure transparent business logic, robust documentation, and full auditability.
  
  

What You'll Need

• Extensive experience as a Senior Software Developer within complex enterprise environments, specifically working with Ruby on Rails.
• Strong background in Business Analysis with a proven ability to challenge and refine requirements from senior Finance and FP&A stakeholders.
• Solid understanding of finance processes, including accounting, controlling, and data integrity within large-scale systems.
• Expertise in modern delivery practices, including Cloud Platforms (AWS/Azure), automated testing, and DevOps-led deployment governance.
• An outcome-focused, pragmatic mindset capable of delivering high-priority solutions within a 6-month time-bound contract.
  
  

What's On Offer

• Competitive day rate of £500 - £600 per day.
• Outside IR35 engagement providing maximum flexibility for limited company contractors.
• Fully remote working model (UK-based) within an innovative team focused on global energy transformation.
• Long-term project stability with a 6-month initial assignment and high-profile technical ownership.
  
  

Apply via Haystack today!