John Rossberg
Code Wizard at Celerblock
Greater Malmö Metropolitan Area Sweden
Summary
🤩
Rockstar🎓
Top SchoolJohn Rossberg is a versatile full-stack engineer with 11 years of experience building performant web and 3D applications for startups and large enterprises, including a key role developing one of IKEA’s most complex wardrobe planners. Comfortable across backend systems (Scala, Node.js, Kafka, Elasticsearch) and modern front-end stacks (React, TypeScript, redux, 3D engines), he blends system architecture work with hands-on coding. He actively experiments in side projects like Matopia and oncourt.se, using them to trial new tech such as full TypeScript, GraphQL, and advanced gesture animations. John’s open-source contributions to the Speedment Java ORM show a depth in database type-mapping and practical bug fixes, reflecting strong attention to data correctness and runtime behavior. Based in Malmö, he now applies this breadth as a "Code Wizard" at Celerblock, bringing creative problem-solving and performance-minded architecture to production systems.
11 years of coding experience
8 years of employment as a software developer
Master's degree Computer Science, Master's degree Computer Science at The Faculty of Engineering at Lund UniversityComputer Science, Computer Science at Zhejiang University
Stackoverflow
1reputation
0reached
1answer
0questions
Github Skills (15)
javas10
databases10
type-mapping10
orm10
java10
database10
sql9
biginteger7
blobs7
bigdecimal7
stream6
nodejs6
code-generation6
mongodb6
ubuntu6
Programming languages (6)
Github contributions (5)
speedment/speedment
Mar 2017 - May 2017
Speedment is a Stream ORM Java Toolkit and Runtime
Role in this project:
Back-end Developer
Back-end DeveloperContributions:5 commits, 3 pushes, 15 issues in 1 month
Contributions summary:John primarily focused on enhancing the Java-based Speedment ORM toolkit. Their contributions included adding support for unsigned numerical types within the database mapping layer, specifically modifying the `JavaTypeMapImpl.java` file to handle unsigned integer and bigint types. They also addressed a bug related to mapping a Blob object to a byte array. Further commits merged develop branches and included improvements to utility methods and type mappings, indicating a focus on database interaction and type management.
javaormspeedmentdatabasestream
rossii123/MatInsp
Dec 2015 - Sep 2019
Contributions:2 pushes, 1 branch in 3 years 10 months
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