Callum Forrester
Senior Software Engineer at Oxford Ionics
Oxford, England, United Kingdom
Summary
👤
Senior🎓
Top SchoolCallum Forrester is a Senior Software Engineer based in Oxford with eight years' experience building experiment orchestration, API-driven systems, and cross-facility integrations for research infrastructure. He progressed through multiple engineering roles at Diamond Light Source, delivering scriptable experiment control, hardware simulation, and Kubernetes-at-the-edge before joining Oxford Ionics. Comfortable across backend systems and distributed architectures, he has contributed to notable open-source projects such as Netflix’s dgs-framework by designing and refactoring a WebSocket subscription client using Spring WebFlux and reactive streams. He combines a research-focused mindset with pragmatic production engineering, often bridging hardware control needs with cloud-native tooling. Known for turning complex experimental requirements into maintainable, scriptable platforms, he brings deep domain knowledge of scientific facilities and practical experience shipping resilient integration layers.
8 years of coding experience
6 years of employment as a software developer
A Levels in Mathematics, Physics and Computing, A Levels in Mathematics, Physics and Computing at Peter Symonds CollegeBachelor of Science (BSc), Computer Science with a Year in Industry, Bachelor of Science (BSc), Computer Science with a Year in Industry at University of Kent
Stackoverflow
21reputation
250reached
0answers
2questions
Github Skills (10)
javas10
graphql10
websocket10
graphql-java10
webflux10
wpgraphql10
wordpress-graphql10
java10
spring-boot10
reactivex6
Programming languages (12)
Github contributions (5)
Netflix/dgs-framework
Aug 2021 - Sep 2021
GraphQL for Java with Spring Boot made easy.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:3 reviews, 29 commits, 1 PR in 1 month
Contributions summary:Callum contributed to the `dgs-framework` by implementing and refactoring the websocket client. They added Spring WebFlux as a compile-only dependency and wrote the initial implementation of the subscription client using websockets and webflux. Further contributions included refactoring the client to use a single session model, and fixing issues with cancelling incoming messages. The user also updated the client interface to use Flux instead of Publisher.
spring-bootdgsgraphql-javaspringgraphql
DiamondLightSource/blueapi
Aug 2022 - Apr 2025
Contributions:36 releases, 530 reviews, 257 PRs in 2 years 7 months
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