Ruffle is a free and open source emulator for playing Adobe Flash (SWF) animation files.

[2] The web client relies on Rust being compiled to WebAssembly, which allows it to run inside a sandbox, a significant improvement compared to Flash Player, which garnered a notoriety for having various security issues.

[3][4] The Rust language itself protects against common memory safety issues that plagued Flash Player, such as use after free or buffer overflows.

[7] As of February 2025, Ruffle supports most older Flash content, which use ActionScript 1.0 and 2.0, with 95% of the language and 79% of the API having been implemented.

[18] In 2019, Newgrounds announced it was sponsoring the development of Ruffle,[19] and would use it for all Flash content, starting with animations and later interactive games.

[26] In July 2023, Neopets announced that the usage of Ruffle was being explored to speed up the process of bringing back broken Flash games and other content to the website.