Mateusz Rzeszutek
Principal Software Engineer I at Elastic
Poland
Summary
🤩
Rockstar🎓
Top SchoolMateusz Rzeszutek is a Principal Software Engineer with a strong Java/JVM pedigree and over a decade of production engineering experience, now shaping platform and observability work at Elastic. He has driven backend platform standards at companies like Revolut and Clari, led Java instrumentation at Splunk, and is an emeritus maintainer and approver in the high-profile OpenTelemetry Java ecosystem—contributions that include auto-instrumentation, semantic conventions, and AWS Lambda resource support. Known for blending hands-on coding with technical leadership, he architects high-throughput distributed systems (Apache Arrow, Kubernetes, AWS) while mentoring engineers and setting design standards. Less obvious: his deep focus on improving HTTP tracing semantics (e.g., HttpRouteHolder, NET_PEER attributes) has materially improved observability across multiple Java frameworks.
5 years of coding experience
12 years of employment as a software developer
Magister inżynier (Mgr inż.), Informatyka, Magister inżynier (Mgr inż.), Informatyka at AGH University of Krakow
English, Polish, Japanese
Stackoverflow
176reputation
6kreached
7answers
0questions
Github Skills (17)
java10
javas10
sdk10
opentelemetry10
resource-management9
aws-lambda9
spring-boot9
apache-camel8
spark7
webflux7
logging6
spring-cloud-sleuth6
test-automation6
instrumentation6
spring6
Programming languages (12)
Github contributions (5)
open-telemetry/opentelemetry-java-instrumentation
Dec 2020 - Jan 2023
OpenTelemetry auto-instrumentation and instrumentation libraries for Java
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1 release, 4175 reviews, 129 commits in 2 years 1 month
Contributions summary:Mateusz's commits focus on auto-instrumentation and instrumentation libraries for Java. Their work involved utilizing `HttpRouteHolder` to enhance instrumentation within various frameworks, including Apache Camel, Spark, and Spring WebFlux, indicating a focus on improving the tracing capabilities of these systems. These changes involved the modification of code and test files to integrate the `HttpRouteHolder` into the instrumentation framework, likely enabling better monitoring and debugging of HTTP requests within these frameworks. Further, the user has demonstrated knowledge of common attributes such as, `NET_PEER_NAME`, `NET_PEER_PORT`, `HTTP_REQUEST_METHOD` etc.
instrumentationinstrumentation-librariesjava-agenttracingauto-instrumentation
open-telemetry/opentelemetry-java
Aug 2020 - Sep 2022
OpenTelemetry Java SDK
Role in this project:Back-end Developer
Back-end DeveloperContributions:611 reviews, 15 commits, 24 PRs in 2 years 1 month
Contributions summary:Mateusz implemented new semantic attributes related to threads and process runtime information within the OpenTelemetry Java SDK, enhancing the tracing capabilities. They added support for AWS Lambda resource attributes, enriching the SDK's ability to capture details in serverless environments. Furthermore, the user contributed to fixing build scripts and added an example using auto-configuration, improving usability and maintainability.
tracingobservabilitysdkotelopentelemetry-java
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