Martin Costello
Staff Software Engineer at Grafana Labs
London, England, United Kingdom
Summary
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Top SchoolMartin Costello is a Staff Software Engineer with 14 years of experience building resilient .NET systems, currently working on OpenTelemetry instrumentation for .NET at Grafana Labs after a senior engineering leadership stint at Just Eat Takeaway. A Microsoft MVP and Certified ScrumMaster with a background in testing and QA, he brings deep expertise in observability, CI/CD and backend engineering across cloud and serverless contexts. Martin is an active open-source contributor to high-profile .NET projects—contributions to octokit.net, ASP.NET Core, AWS Lambda for .NET and Dependabot demonstrate his focus on reliability, tooling and developer experience. He combines a physics degree from the University of Birmingham with a pragmatic engineering approach, often surfacing subtle fixes (typos, error messages, IDisposable patterns) that materially improve library robustness. Notably, his work spans both feature implementation (OAuth providers, API clients) and infrastructure-level improvements (benchmarking, SDK containerization), making him comfortable from code-level bug fixes to build and release automation.
14 years of coding experience
12 years of employment as a software developer
High School, High School at King Edward VI Camp Hill School For BoysBSc (Hons) Physics & Astrophysics, BSc (Hons) Physics & Astrophysics at University of Birmingham
Stackoverflow
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Github Skills (88)
dependency-management10
nuget10
benchmark10
dependency-analysis10
testing10
swagger10
asp-net-core10
cancellationtoken10
asp-net10
http-client10
build-automation10
netcore10
social-authentication10
refactoring10
backend10
Programming languages (22)
Github contributions (5)
aspnet-contrib/AspNet.Security.OAuth.Providers
May 2017 - Dec 2022
OAuth 2.0 social authentication providers for ASP.NET Core
Role in this project:
Backend Developer
Backend DeveloperContributions:57 releases, 546 reviews, 386 commits in 5 years 8 months
Contributions summary:Martin primarily contributed to the development of OAuth 2.0 social authentication providers for ASP.NET Core, based on the repository description and topics. Their commits focused on adding new providers, specifically for Amazon and potentially others, suggesting feature implementation and integration work. These changes involved creating middleware, authentication handlers, and related configuration files, indicating a strong focus on backend implementation.
social-authenticationoauth-2aspauthenticationproviders
App-vNext/Polly
Jan 2021 - Jan 2023
Polly is a .NET resilience and transient-fault-handling library that allows developers to express policies such as Retry, Circuit Breaker, Timeout, Bulkhead Isolation, and Fallback in a fluent and thread-safe manner. From version 6.0.1, Polly targets .NET Standard 1.1 and 2.0+.
Role in this project:Backend & DevOps Engineer
Backend & DevOps EngineerContributions:17 releases, 1340 reviews, 69 commits in 2 years
Contributions summary:Martin primarily contributed to the build and test infrastructure, addressing build failures and updating the build configuration. They focused on improving the CI/CD pipeline by targeting .NET 6, integrating code coverage tools, and switching to GitHub Actions. Additionally, the user worked on updating NuGet packages and the project versioning. The user also implemented rate-limit policy and made fixes to the codebase.
circuit-breakerfaulttransient-fault-handlingexpressfallback
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