Senior Software Engineer; JVM, Kotlin

Simple Machines is a leading independent boutique technology firm with a global footprint across London, Sydney, San Francisco, and New Zealand. We operate at the intersection of data, AI, machine learning, data engineering, and software engineering—building bespoke platforms and products that turn complex data into real‑world outcomes. We work with enterprises, technology companies, and governments to help them better understand their organisations, customers, and citizens.

Senior Software Engineer (JVM, Kotlin) – Hybrid
• Full‑time
• London, UK

Our teams design and build large‑scale data platforms, intelligent systems, and high‑impact software products. We engineer data to life™.

As a Senior Software Engineer
, you’ll play a key role in delivering complex, scalable systems for ambitious clients. This is a hands‑on engineering role where you’ll work across the full stack—backend services, APIs, frontend components, data pipelines, and cloud infrastructure.

• Design and build backend services for a highly scalable marketing platform
• Own the design of APIs, applications, and supporting infrastructure
• Document technical designs and requirements clearly for both internal teams and clients
• Deliver solutions end‑to‑end: build, automate, deploy, operate, and support
• Partner with clients and delivery teams to translate business requirements into robust technical solutions
• Work within an Agile, iterative delivery model
• Collaborate in a hybrid setup with both remote and in‑person team members and stakeholders

You’ll join a high‑performing engineering team working on a large‑scale machine learning platform for a global telecommunications client. The team operates with a high degree of autonomy and shared ownership. Engineers work across the full stack, support one another’s growth, and collaborate closely with data scientists and adjacent teams to design cross‑system solutions.

• Strong foundation in JVM‑based development (Kotlin preferred, Java welcome)
• Experience designing and implementing data‑driven APIs
• Background working on large‑scale web services
• Solid SQL experience, including schema design and performance‑aware queries
• Deep experience with automated testing (unit, integration; TDD/BDD preferred)

• Experience with React, Type Script, Redux, and Tailwind (or similar modern frameworks)

• Experience with AWS, GCP, Azure, or similar
• Infrastructure‑as‑code (Terraform, Cloud Formation, etc.)
• Containerised deployments using Docker, ECS, Kubernetes, or equivalent

• Exposure to Scala or functional programming concepts
• Experience with asynchronous and highly concurrent backend frameworks (e.g. Ktor, http4k, Play, RxJava)
• No
  
  SQL experience (Dynamo
  
  DB, Cassandra, Big Table, Cosmos DB, etc.)
• Strong Git workflow experience and the ability to adapt workflows to project needs
• A genuine appetite for learning and adopting new technologies quickly