Discord & Slack (Messaging & Social Apps): open-source projects that exist because someone reverse engineered a closed product, sorted by GitHub stars.
The cutest Discord modification
Exports Discord chat logs to HTML, JSON, CSV or text files
Better Discord enhances Discord desktop app with new features.
Custom Discord desktop app with Vencord preinstalled
Free, self-hostable reimplementation of a Discord-compatible chat platform and API
A lightweight, secure, and feature-rich Discord terminal (TUI) client.
Open-source rewrite of Discord desktop's app.asar
Save or export your private and public Slack messages, threads, files, and users locally without admin privileges.
Reimplementation of the Discord.com backend, compatible with Discord clients
Tiny native Discord app
Datamining Discord changes from the JS files
Fork of discord.py wrapping Discord's user (self-bot) API
An unofficial discord.js fork for creating selfbots
Lightweight Discord client mod, continuation of Powercord
C# implementation of the Discord Rich Presence IPC protocol
A Golang library and framework for the Discord API.
Unofficial Discord User API Documentation
Documentation of undocumented Slack API methods
A CLI / TUI for Microsoft Teams
Slack module for libpurple
Client modification for Discord Android
Reverse engineered Discord user settings protobufs
A Matrix-Slack puppeting bridge
Unofficial Discord client for the Nintendo 3DS
Moved to https://git.dere.net/oldcord/oldcord
Reverse engineered Discord API that mimics the official web client
Unofficial wrapper for the MEE6 Discord bot levels API: leaderboards, role rewards and XP
Unofficial module to launch Discord's beta Activities such as YouTube Together
Unofficial client for discord build in C++ with Qt.
Unofficial Micorosoft Teams client/cli
Unofficial Discord API documentation
Unofficial Discord overlay support for macOS
Decompilation of Discord's updater.node
Unofficial Python API for the MEE6 Discord bot leaderboards
Reverse-engineered Discord client code
Kotlin library talking to Discord as the Android app, reverse-engineered from the official client
Regenerates Slack's withdrawn OpenAPI spec by analysing the Slack Node SDK
Unofficial documentation for undocumented Discord APIs
Reimplementation of Discord's local RPC server for third-party rich presence