The April 2019 edition of Release Radar highlights a range of innovative projects, each reaching significant milestones with version 1.0 releases, showcasing advancements across gaming, design, web development, and localization tools. SuperTuxKart introduces network multiplayer in its 3D arcade racing game, while Termshark debuts as a visual interface for analyzing network traffic. The United States Web Design System 2.0 enhances federal web services with increased modularity and accessibility. Docz and MDX streamline the creation of documentation and content integration, respectively, fostering ease and flexibility in development processes. GB Studio enables the creation of 2D adventure games without coding experience, and Uppy enhances file uploading with new features. Fluent offers an expressive localization system, and Caddy emphasizes secure web server functionalities. Babylon.js 4.0 improves WebGL graphics with performance enhancements and a scene inspector. Additional projects like Quinesnake and Tinkersynth showcase creative endeavors in programming and generative art. These projects collectively demonstrate the diverse and impactful contributions of the open-source community.