diff --git a/pkgs/slippi-launcher/default.nix b/pkgs/slippi-launcher/default.nix
new file mode 100644
index 0000000..15c76db
--- /dev/null
+++ b/pkgs/slippi-launcher/default.nix
@@ -0,0 +1,183 @@
+{ lib
+, fetchFromGitHub
+, electron
+, nodejs
+, makeWrapper
+, git
+, stdenv
+, yarnConfigHook
+, fetchYarnDeps
+}:
+
+# Similar derivations:
+#   - Logseq: https://github.com/NixOS/nixpkgs/blob/nixos-25.05/pkgs/by-name/lo/logseq/package.nix#L283
+#   - Podman: https://github.com/NixOS/nixpkgs/blob/224042e9a3039291f22f4f2ded12af95a616cca0/pkgs/applications/virtualization/podman-desktop/default.nix
+
+stdenv.mkDerivation (final: {
+  pname = "slippi-launcher";
+  version = "2.11.10";
+
+  src = fetchFromGitHub {
+    owner = "project-slippi";
+    repo = "slippi-launcher";
+    rev = "v${final.version}";
+    hash = "sha256-EWKxzGLjyJ15wGioUtfh3biU7Pfa5bYtV1Om2w5IZW8=";
+    leaveDotGit = true;
+  };
+
+  patches = [
+    # Dependency with git+https protocol breaks yarnConfigHook.
+    ./fix-git-deps.patch
+  ];
+
+  # Avoid network error during build.
+  # https://stackoverflow.com/questions/78004799/78004800
+  env.ELECTRON_SKIP_BINARY_DOWNLOAD = 1;
+
+  buildInputs = [
+    electron
+  ];
+
+  nativeBuildInputs = [
+    yarnConfigHook
+    nodejs
+    electron
+    git
+    makeWrapper
+  ];
+
+  # Disable the default usage of yarnConfigHook.  We instead opt to run the hook
+  # manually (several times) for reasons made clear in the commentary on this
+  # package's `postConfigure` script.
+  dontYarnInstallDeps = true;
+
+  configurePhase =
+    let
+      # Constants to be set in the .env file.  Slippi contains an example .env
+      # file here:
+      # https://github.com/project-slippi/slippi-launcher/blob/main/.env.example
+      dotenv = {
+        # N.B. although these values are *not* secrets (yes, even the API key), they
+        # were extracted from the AppImage release.
+        FIREBASE_API_KEY = "AIzaSyAuQqc_wgqcUu3FqrICEPZ9Av_hPxMR_i4";
+        FIREBASE_AUTH_DOMAIN = "slippi.firebaseapp.com";
+        FIREBASE_DATABASE_URL = "https://slippi.firebaseio.com";
+        FIREBASE_PROJECT_ID = "slippi";
+        FIREBASE_STORAGE_BUCKET = "slippi.appspot.com";
+        FIREBASE_MESSAGING_SENDER_ID = "101358986051";
+        FIREBASE_APP_ID = "1:101358986051:web:1e361ce2a76dfd1b0f85f6";
+        FIREBASE_MEASUREMENT_ID = "G-VNB1EB87Y2";
+
+        # Ditto.
+        SLIPPI_WS_SERVER = "ws://broadcast-dot-slippi.uc.r.appspot.com/";
+        SLIPPI_GRAPHQL_ENDPOINT = "/graphql";
+      };
+    in ''
+      runHook preConfigure
+
+      # For reasons I don't quite understand[1], this package is split across two
+      # `package.json` files.  We call yarnConfigHook once for each package.json
+      # to install their respective dependencies.  Each yarnConfigHook call uses a
+      # separate offline cache.
+      #
+      # [1]: https://www.electron.build/tutorials/two-package-structure.html
+      yarnOfflineCache="$yarnOfflineCacheRoot" yarnConfigHook
+
+      pushd release/app
+      yarnOfflineCache="$yarnOfflineCacheRelease" yarnConfigHook
+      popd
+
+      # Merge the dependencies listed in release/app/package.json into the
+      # node_modules/ directory corresponding to the top-level package.json.
+      # This feels very wrong!  Surely there's a better way…
+      for i in release/app/node_modules/*; do
+        dest="node_modules/$(basename "$i")"
+        if [[ ! -f "$dest" ]]; then
+          mv "$i" "$dest"
+        fi
+      done
+
+      # Populate the .env file.
+      tee .env << EOF
+      ${lib.concatLines
+        (lib.mapAttrsToList (k: v: "${k}=${v}") dotenv)}
+      EOF
+
+      runHook postConfigure
+    '';
+
+  buildPhase = ''
+    runHook preBuild
+
+    cp -r ${electron.dist} electron-dist
+    chmod -R u+w electron-dist
+
+    # Run builds concurrently.  Taken from Slippi's `yarn run package` script,
+    # but we've added the `--ofline` flag.
+    yarn --offline run build:main &
+    yarn --offline run build:renderer &
+    yarn --offline run build:migrations &
+    wait
+
+    # Build to release/build/linux-unwrapped.  The flag `--dir` stops
+    # electron-builder before creating an AppImage.
+    ./node_modules/.bin/electron-builder \
+      build --dir --publish never \
+      -c.electronDist=electron-dist \
+      -c.electronVersion=${electron.version}
+
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out/{bin,opt/slippi-launcher}
+    cp -r release/build/linux-unpacked/* $out/opt/slippi-launcher
+
+    # Electron programs need to differentiate between production and
+    # non-production builds, and they do so by testing if argv[0] is 'electron'
+    # or not.  Thus, --inherit-argv0 should be all we need; however, this is not
+    # the case.  God knows why.  Just suck it up and set
+    # ELECTRON_FORCE_IS_PACKAGED=true.
+    makeWrapper '${lib.getExe electron}' $out/bin/slippi-launcher \
+      --add-flags "$out/opt/slippi-launcher/resources/app.asar" \
+      --add-flags "\''${NIXOS_OZONE_WL:+\''${WAYLAND_DISPLAY:+--ozone-platform=wayland --enable-features=WaylandWindowDecorations --enable-wayland-ime=true}}" \
+      --prefix LD_LIBRARY_PATH : $out/opt/slippi-launcher \
+      --inherit-argv0 \
+      --set ELECTRON_FORCE_IS_PACKAGED true
+
+    runHook postInstall
+  '';
+
+  yarnOfflineCacheRoot = fetchYarnDeps {
+    name = "slippi-launcher-yarn-deps-root";
+    # One of our patches modifies the (top-level) Yarn lockfile and thus must be
+    # visible to fetchYarnDeps.
+    inherit (final) src patches;
+    hash = "sha256-Crq9XywLtEc8IImkldodZJ823YG6dB8D9qGksH/lb3I=";
+  };
+
+  yarnOfflineCacheRelease = fetchYarnDeps {
+    name = "slippi-launcher-yarn-deps-resources";
+    # Our patches don't touch the lockfile at release/app/yarn.lock, so there's
+    # no need to inherit patches }:).
+    inherit (final) src;
+    sourceRoot = "${final.src.name}/release/app";
+    hash = "sha256-iCFqgy+jRaMCoGC77iXkEh964cZAtXFRfdOOJaRTfLc=";
+  };
+
+  meta = {
+    description = "The way to play Slippi Online and watch replays.";
+    longDescription = ''
+      The Slippi Launcher acts as a one stop shop for everything Slippi
+      related. It handles updating Slippi Dolphin, playing Slippi Online,
+      launching and analyzing replays, and more.
+    '';
+    license = lib.licenses.gpl3;
+    homepage = "https://github.com/project-slippi/slippi-launcher";
+    changelog =
+      "https://github.com/project-slippi/slippi-launcher/releases/tag/v${final.version}";
+    platforms = lib.platforms.all;
+  };
+})
diff --git a/pkgs/slippi-launcher/fix-git-deps.patch b/pkgs/slippi-launcher/fix-git-deps.patch
new file mode 100644
index 0000000..b9c4f4b
--- /dev/null
+++ b/pkgs/slippi-launcher/fix-git-deps.patch
@@ -0,0 +1,16 @@
+diff --git a/yarn.lock b/yarn.lock
+index 6b2fba28..40ed0fc4 100644
+--- a/yarn.lock
++++ b/yarn.lock
+@@ -1848,9 +1848,9 @@
+     global-agent "^3.0.0"
+     global-tunnel-ng "^2.7.1"
+ 
+-"@electron/node-gyp@git+https://github.com/electron/node-gyp.git#06b29aafb7708acef8b3669835c8a7857ebc92d2":
++"@electron/node-gyp@https://github.com/electron/node-gyp#06b29aafb7708acef8b3669835c8a7857ebc92d2":
+   version "10.2.0-electron.1"
+-  resolved "git+https://github.com/electron/node-gyp.git#06b29aafb7708acef8b3669835c8a7857ebc92d2"
++  resolved "https://github.com/electron/node-gyp#06b29aafb7708acef8b3669835c8a7857ebc92d2"
+   dependencies:
+     env-paths "^2.2.0"
+     exponential-backoff "^3.1.1"