Senior Engineer at Haystack, United Kingdom, £Contract Rate

My client are looking for a UK-based remote **Senior API Product Engineer**

• Outside IR35
• 5 months initially (good chance of extension)
• Remote
  
  

**Overview**

You build and own APIs as products.

You focus on outcomes, not tickets.

You work hands-on across the full API lifecycle.

You follow platform standards while contributing to shared tooling and patterns.

This role suits someone who blends strong engineering with product ownership.

**What you will do**

**Design and build APIs**

Design APIs aligned to agreed standards, including naming, versioning and security, work with domain data models, build REST and event-driven APIs, keep consistency across platform patterns

**Use and improve platform tooling**

Use shared CI/CD pipelines, templates and reference architectures

• Follow established patterns
• Improve and contribute reusable API assets
  
  

**Own the full API lifecycle**

• Design, build, test, deploy and operate APIs
• Manage versioning strategy
• Maintain backward compatibility
  
  

**Deliver integrations**

• Integrate with internal systems and data platforms
• Handle data transformation across services
• Apply synchronous and asynchronous patterns
• Build for resilience, including retries, timeouts and fallback
  
  

**Implement security**

• Apply authentication, including OAuth2 and client credentials
• Follow platform-led authorisation models
• Align with central identity approaches
  
  

**Enable observability**

• Implement logging, metrics and tracing
• Support monitoring through shared platform tools
• Ensure services remain observable and supportable
  
  

**Collaborate across teams**

• Work with QA, platform engineering and product stakeholders
• Contribute to engineering standards and governance forums
• Align with wider delivery and architecture direction
  
  

**Deliver in an agile environment**

• Ship iteratively under tight timelines
• Manage cross-team dependencies
• Balance speed with compliance to standards
  
  

**What you bring**

**Technical experience**

• Strong API engineering across REST and event-driven systems
• Experience with cloud-native development, ideally Azure
• CI/CD and infrastructure as code awareness
• Strong understanding of integration patterns, sync and async
• Experience implementing OAuth2 security
• Familiarity with API management platforms
  
  

**Platform mindset**

• Comfortable working within guardrails
• Experience using shared tooling and frameworks
• Pragmatic approach to standardisation vs flexibility