Project Slippi

Project Slippi is an ongoing project that aims to give Super Smash Bros. Melee several major quality of life features originally not present in the game. As of June 2020, the features currently included are automatically saved replays, live match mirroring, rollback netcode, and integrated online matchmaking. The project was created and is being led by Fizzi with major contributions from UnclePunch, Nikki, and metaconstruct.

Components

 * Slippi Launcher: This launcher features the ability to open and play .slp replay files.
 * Slippi Online: This is a custom version of Dolphin that allows for online netplay featuring rollback netcode, integrated matchmaking, and automatically saved replays.
 * Nintendont-Slippi: This is a custom build of Nintendont that features support for writing replay files onto SD cards or USB flash drives, transferring live-replays over network, and toggling quality of life changes. The network transferring feature allows for live mirroring between the console and Dolphin which is suitable for high quality Melee streaming.

Unofficial components
A number of unofficial Slippi-compatible projects have been created by the community for various purposes.


 * Lylat: A project that enables the use of compatible gameplay modifications with Slippi Online. Currently supported modifications include The Akaneia Build, Beyond Melee, and Melee 1.03.
 * Project Clippi: A toolkit that allows users to automatically execute actions when an in-game event occurs. The most notable use of this is the ability to automatically clip or record combos or other specific interactions as soon as they occur.
 * Stats Graphics Generator: A website that automatically generates a graphic detailing the stats and results of an inputted .slp file.
 * Gecko Codes: Various codes that can be inputted into the "Cheat Code Editor" section of Dolphin and Slippi that add features and manipulate the code of compatible games. Notable codes for Melee and Brawl include exposing stage geometry, visual and audible indicators for specific actions, and adding and removing certain glitches and exploits. There are also general quality of life codes like improved resolution and audio quality and the Universal Controller Fix.
 * Diet Melee: A gameplay modification of Melee designed to make the game run more efficiently with Slippi on more modest configurations. It greatly reduces the polygon count of every tournament legal stages, replace characters models with their low-poly version, and deletes from the game every non-essential file, like trophies, non-legal stages and all single player content. Three builds of the mod are available : the standard Diet Melee Classic, the SSB64-styled Diet Melee 64 that uses models and textures resembling Super Smash Bros., and the even more stripped-down Diet Crystal Melee aiming for maximum visual clarity with minimalist models and textures.

Features

 * Replays: Project Slippi automatically generates replays after any match is played. These replays are saved as .slp files which can be opened on computers using the Slippi Launcher. Detailed statistics on the match, such as the amount of neutral wins, kills, and damage dealt, are included alongside the replays.
 * Live mirroring: Nintendont-Slippi features the ability to accurately mirror console inputs onto Dolphin. This feature allows for streams to show high quality footage from Dolphin rather than from the actual console. This feature has seen use at many major tournaments including, , and.
 * Rollback netcode: The dolphin build of Slippi introduces rollback netcode into the game. This allows for games to occur between large distances with almost zero latency.
 * Integrated matchmaking: The dolphin build of Slippi also introduces integrated matchmaking. Players are able to queue up against other random players without needing any external applications or websites.

History
The project was publicly launched on June 18th, 2018, but had been in a "private beta" since February of that year. The initial release featured automatically saved replays and detailed match statistics. Prior to this launch, the statistics system was previously used at, , and for use on stream. On September 29th, 2018, Smashladder announced that Project Slippi had become the community's main Dolphin build.

On January 13th, 2019, a stream would be held announcing a feature that enabled live mirroring from console to Dolphin. This would allow for high quality streaming of the game with no additional hardware required. This feature was in "beta" and accessible to Patreon supporters until March 10th when it was released to the public. On February 22nd, would become the first tournament to use Project Slippi for high quality streaming of the event. On March 9th, would become the first North American tournament to use Project Slippi. Every tournament setup featured the ability to automatically save replays and the stream also utilized Slippi for data analysis and high quality streaming. On the same day, slippi.gg would be launched. This website includes downloads of the project as well as nearly every replay from The Gang Steals The Script. From this point forward, every future major tournament utilizing Slippi would now appear on the website. On April 20th, 2019, a feature would be added to the website that would allow users to preview games via a lightweight in-browser visualizer designed by Will Blackett. On November 27th, Fizzi would announce that he would begin working on Slippi full-time.

On June 22nd, 2020, an update was released for the custom Slippi Dolphin build that would introduce rollback netcode and integrated matchmaking into the game. This became a major breakthrough in the competitive Super Smash Bros. Melee community as distance-based latency would no longer be an issue. Due to the COVID-19 pandemic, most in-person tournament activity had been completely shut down since March 2020, and Project Slippi became the dominant method of playing Melee, with major tournament organizers hosting events using the new updates. Project Slippi has since been credited with bringing new players into the competitive Melee scene, due to its ease of access and ability to provide practice against anyone online.

On January 19th, 2021, v2.2.4 was released, introducing a hidden match-making rating (MMR) into random unrated matches. The update restricted the search range for players with low MMR dramatically while maintaining a wide search range for players of average skill or better. This was aimed at creating more balanced matchups at lower levels of play, preventing newer players from receiving crushing defeats against more experienced players, and increasing new player retention levels.

On December 17th, 2023, Fizzi announced that he would be flying out, , , and (four prolific players of Slippi's ranked mode) to. This was a thank-you gift to the four players for their continued support, who were to play under the banner of "Ranked Mode" at the tournament.