It features a preemptive kernel, currently supports x86-64, ARM, and RISC-V[1][2] based computers, and hosts multiple complex applications including its own web browser and integrated development environment (IDE).

[14] The system is written in what the authors call "Serenity C++",[15] a C++ coding style that avoids exceptions and features its own standard library.

[16] The relative popularity of SerenityOS compared to other hobbyist systems is in part due to the modest success of Kling's YouTube channel, where he uploaded videos of himself developing parts of the system alongside demos and monthly progress updates (until April 2024, where the last update was hosted by Andrew Kaster, project’s core developer).

[18] SerenityOS includes a version of the Ladybird web browser, built from the ground up using its internal libraries LibWeb, LibJS and LibWasm.

[22] On June 3rd, 2024, Kling announced his plans to fork Ladybird and begin development on the browser as a separate project.