Julien Roncaglia
Staff Software Engineer at sunday
Paris, Ile-de-France
Summary
🤩
Rockstar🎓
Top SchoolJulien Roncaglia is a Staff Software Engineer based in Paris with 20 years of hands-on full-stack experience and a strong leaning toward backend and architecture. Self-taught across many languages—from Delphi and PHP to C#, F#, TypeScript and Rust—he has led web projects from scratch (notably Zenly Web at Snap) and designed event-sourced, CQRS backends and authentication systems. He contributes to prominent open-source tooling in the .NET/F# ecosystem (Paket, FAKE) and has improved developer tooling and CI workflows, reflecting a taste for build systems and automation. Julien combines low-level Windows API and P/Invoke work with modern gRPC/tonic and ScyllaDB-powered microservices, showing both systems-level and service-oriented expertise. Known for pragmatic, maintainable solutions, he also brings unexpected breadth—from UI tweaks in GitHub Desktop to Roslyn analyzers and secure auth prototypes at scale.
20 years of coding experience
21 years of employment as a software developer
BTS, Informatique de Gestion, BTS, Informatique de Gestion at Lycée Marie curie, Marseille
English, French
Stackoverflow
17,567reputation
1.3mreached
236answers
3questions
colors
top-5%
linq
top-5%
console-application
top-5%
command-line
top-5%
cmd
top-5%
reflection
top-5%
Github Skills (74)
nuget10
pywin3210
github10
package-management10
wp-api10
testing10
winapi10
interop10
asp-net10
javas10
junit10
code-analysis10
build-automation10
fsharp10
refactoring10
Programming languages (15)
Github contributions (5)
dotnet/pinvoke
Oct 2015 - Feb 2018
A library containing all P/Invoke code so you don't have to import it every time. Maintained and updated to support the latest Windows OS.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:178 commits, 53 PRs, 18 pushes in 2 years 4 months
Contributions summary:Julien contributed significantly to the `dotnet/pinvoke` repository, focusing on enriching the project by adding new definitions for the Win32 error codes. They also added definitions for functions and structures related to the Hid.dll, which is indicative of working with low-level Windows API interaction. Furthermore, the user demonstrated a focus on code quality by fixing style issues and addressing build errors.
dotnetwindowsos-windowspinvokeupdated
ionide/ionide-vscode-fsharp
Aug 2017 - Sep 2019
VS Code plugin for F# development
Role in this project:Full-stack Developer
Full-stack DeveloperContributions:56 commits, 38 PRs, 74 comments in 2 years 1 month
Contributions summary:Julien contributed significantly to the Ionide VS Code plugin for F# development. They implemented new features such as an "Open project file" command and enhancements to the solution explorer, including improved icon theming and removing unnecessary file levels. Further contributions addressed bugs in the language service and improved the GoTo definition functionality for #load directives. Their work also involved code cleanup and improvements to UI elements within the VS Code environment.
editor-pluginfsharpvscodevscode-extensionionide
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.