System Integration Engineer

OB Collective is a UK technology business working on independent verification and evidence for information moving between organisations and systems. We work primarily in regulated and public-sector environments, combining software engineering, systems assurance and operational evidence to help organisations understand the state of information before it is relied upon. We're looking for a Senior Integration & Platform Engineer for an initial six-month software-intensive technical programme. The role owns the integration and technical environment around an existing software prototype. You will work across system interfaces, event-driven data flows, test tooling, deployment and instrumentation, making sure the platform can be run and tested reliably under normal, degraded and higher-load conditions. This is primarily a backend, integration and platform engineering role rather than front-end development. We need someone comfortable working with an existing codebase, connecting it to other systems and building the tooling needed to understand how it behaves. The work starts from an existing software prototype and will cover system integration, testing, failure conditions, performance and resilience, and the evidence needed to support future operational use. Roles are UK-based, outside IR35, and primarily remote with occasional travel for workshops and technical activity. Responsibilities

• Design and build interfaces and ingestion adapters between systems.
• Integrate the existing software with representative data sources and external interfaces.
• Build replay, scenario and test-support tooling.
• Develop controlled fault-injection capabilities.
• Support testing of data transformation and fidelity between systems.
• Instrument the platform for latency, throughput, queues, processing time and resource use.
• Build and maintain reproducible development and test environments.
• Maintain CI/CD pipelines and automated regression testing.
• Support performance, concurrency, overload and resilience testing.
• Work with recorded, simulated and pseudo-live data.
• Maintain clear interface, deployment and environment documentation.
• Work closely with the Technical Authority and Test, Evaluation & Measurement Lead.
• Provide second-person technical resilience around building, deploying and operating the wider platform.
• Diagnose integration and platform issues across multiple components rather than treating each system in isolation. Experience we need
• Strong senior backend, platform or integration engineering experience.
• Good understanding of distributed and event-driven systems.
• Experience designing and integrating APIs and system interfaces.
• Experience with messaging, streaming or event-processing technologies.
• Strong containerisation and deployment experience.
• CI/CD and automated testing experience.
• Experience with instrumentation and observability.
• Performance, load or resilience testing experience.
• Comfortable working in an established codebase rather than only greenfield development.
• Strong troubleshooting skills across systems and interfaces.
• Able to document technical decisions and interfaces clearly. Useful experience
• Rust
• Scala/JVM
• Go
• Apache Kafka or similar event-streaming platforms
• Kubernetes
• Cloud and on-premise environments
• Disconnected or constrained deployments
• Aviation, aerospace, defence, transport or other regulated environments
• Systems handling positional, telemetry or time-sensitive data