Keefer Kosciuch
Senior Site Reliability Engineer (L6) at Block
Old Toronto, Ontario, Canada
Summary
🤩
Rockstar🎓
Top SchoolKeefer Kosciuch is a Senior Site Reliability Engineer with 11 years of experience building high-throughput, secure systems and leading reliability platforms across Block brands. He blends deep systems and networking expertise—from low-level browser File I/O work at Mozilla to service graph and microservice coordination at Cash App—with strong security and privacy instincts. Keefer has shipped production-ready tooling that prevents outages and defends supply chains, and contributed to notable open-source projects like Vitess and Cash App’s misk framework. He leads with empathy and transparent leadership, preferring to fix root causes rather than apply temporary workarounds. Outside large-scale services, he applies engineering to humanitarian tech in the Circumpolar North and maintains practical automation projects like cursor theming and HiDPI asset pipelines. He is driven by a belief that technology should tangibly serve users and be a force for good.
11 years of coding experience
9 years of employment as a software developer
High School Mathematics and Computer Science, High School Mathematics and Computer Science at Cameron Heights Collegiate InstituteIB Certificates in Chemistry and Mathematics Mathematics, IB Certificates in Chemistry and Mathematics Mathematics at International BaccalaureateBachelor of Computing (B. Comp.) Honours Computer Science (CO-OP), Bachelor of Computing (B. Comp.) Honours Computer Science (CO-OP) at University of Guelph
English, French
Stackoverflow
101reputation
4kreached
0answers
2questions
Github Skills (36)
kotlin10
docker10
testing10
microservices-application10
bash10
dockers10
guice10
java10
javas10
automation10
go10
build-automation10
inkscape10
automations10
microservices10
Programming languages (25)
Github contributions (5)
keeferrourke/capitaine-cursors
Jul 2016 - May 2020
An x-cursor theme inspired by macOS and based on KDE Breeze. Designed to pair well with my icon pack, La Capitaine.
Role in this project:
Automation Engineer / Build & Release Engineer
Automation Engineer / Build & Release EngineerContributions:5 releases, 56 commits, 19 PRs in 3 years 10 months
Contributions summary:Keefer primarily focused on automating the build process and improving the project's structure. They refactored the build script, moved files, and updated the project's structure to be more intuitive, including moving the build directory. They also introduced HiDPI support by resizing and organizing SVG assets and updating the build process to handle multiple DPIs.
desktop-environmenticonkdegnu-linuxxcursor
cashapp/misk
May 2019 - Jan 2023
Microservice Kontainer
Role in this project:Backend Developer
Backend DeveloperContributions:117 reviews, 96 commits, 115 PRs in 3 years 8 months
Contributions summary:Keefer's commits primarily focus on building the `ServiceGraphBuilder` functionality within the `misk` repository. These commits involve developing core backend features related to managing the startup and shutdown of microservices, including dependency and enhancement handling. The contributions include significant work on cycle detection, testing, API finalization, and general code cleanup and documentation. They also implemented Guice integration with ServiceModules for the service graph.
dockermicroservicemicroservices
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