Senior API Developer (Contract)

About the role

Our client, a leading communications‑technology company, is looking for a Senior API Developer on a six‑month contract. You will design, build and maintain secure, high‑performance APIs that expose enterprise data products, analytical insights, customer scores and machine‑learning outputs to internal systems, partners and external consumers.

Key responsibilities

• Design, develop and maintain secure RESTful and/or GraphQL APIs for data products, insights and ML services.
• Implement authentication, authorisation and security controls such as OAuth2, JWT and API gateways.
• Build integration layers between data platforms, ML services, portals and external systems.
• Ensure APIs are scalable, resilient and performant under high‑volume usage.
• Document, version and govern APIs according to enterprise standards.
• Collaborate with solution architects, data engineers, MLOps, platform and full‑stack teams.
• Monitor, log, troubleshoot and resolve production incidents.
• Maintain compliance with data‑privacy, security and regulatory requirements.
• Participate in Agile ceremonies and drive continuous engineering improvement.

Required profile

• Bachelor’s degree in Computer Science, IT, Software Engineering or related field.
• 5–10 years of experience in API development or backend engineering.
• Proven track record designing and delivering RESTful and/or GraphQL services.
• Experience with microservices architecture and distributed systems.
• Familiarity with Agile delivery environments.

Required skills

• RESTful API design
• GraphQL
• Java
• .NET
• Python
• Node.js
• Go
• OAuth2
• JWT
• API gateways (e.g., Apigee, Azure API Management, Kong)
• Microservices architecture
• Distributed systems
• Data platform integration
• Machine‑learning service integration
• Cloud platforms: Azure, AWS, Google Cloud Platform
• Agile methodology