diff --git a/.envrc b/.envrc
new file mode 100644
index 00000000000..3550a30f2de
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/.gitignore b/.gitignore
index 31d4a2c5813..f1a5c63a499 100644
--- a/.gitignore
+++ b/.gitignore
@@ -25,6 +25,11 @@ out/
 .gradle/
 build/
 
+# Nix / direnv
+.direnv/
+result
+result-*
+
 # Python cache
 __pycache__/
 
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 00000000000..7b3d5fba80c
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,138 @@
+{
+  "nodes": {
+    "android-nixpkgs": {
+      "inputs": {
+        "devshell": "devshell",
+        "flake-utils": "flake-utils",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1778878828,
+        "narHash": "sha256-bYqGZNxF7RTcbUeAiMkGzT6cOC/PLNSNGwMwZ+ZcBuM=",
+        "owner": "tadfisher",
+        "repo": "android-nixpkgs",
+        "rev": "723e547172f0b3358f7dbf16883cfb9b27c06643",
+        "type": "github"
+      },
+      "original": {
+        "owner": "tadfisher",
+        "repo": "android-nixpkgs",
+        "type": "github"
+      }
+    },
+    "devshell": {
+      "inputs": {
+        "nixpkgs": [
+          "android-nixpkgs",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1768818222,
+        "narHash": "sha256-460jc0+CZfyaO8+w8JNtlClB2n4ui1RbHfPTLkpwhU8=",
+        "owner": "numtide",
+        "repo": "devshell",
+        "rev": "255a2b1725a20d060f566e4755dbf571bbbb5f76",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "devshell",
+        "type": "github"
+      }
+    },
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1778716662,
+        "narHash": "sha256-m1Yf0wZ8j1OHjTc2UwHwyQRSnNeSgLJOd7q5Y45hzi4=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "f7c1a2d347e4c52d5fb8d10cb4d94b5884e546fb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1778737229,
+        "narHash": "sha256-6xWoytx8jFW4PF1GjRm/i/53trbpKGfz6zjzQGBr4cI=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "d7a713c0b7e47c908258e71cba7a2d77cc8d71d5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-25.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1777168982,
+        "narHash": "sha256-GOkGPcboWE9BmGCRMLX3worL4EMnsnG8MyKmXNeYuhQ=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "f5901329dade4a6ea039af1433fb087bd9c1fe14",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "android-nixpkgs": "android-nixpkgs",
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 00000000000..6f0910815f7
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,45 @@
+{
+  description = "uchar element x — reproducible dev environment";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
+
+    flake-parts.url = "github:hercules-ci/flake-parts";
+
+    android-nixpkgs = {
+      url = "github:tadfisher/android-nixpkgs";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs =
+    { self, flake-parts, ... }@inputs:
+    flake-parts.lib.mkFlake { inherit inputs; } (
+      { ... }:
+      {
+        systems = [
+          "x86_64-linux"
+          "aarch64-linux"
+          "x86_64-darwin"
+          "aarch64-darwin"
+        ];
+
+        perSystem =
+          { pkgs, system, ... }:
+          {
+            _module.args.pkgs = import inputs.nixpkgs {
+              inherit system;
+              config.allowUnfree = true;
+              config.android_sdk.accept_license = true;
+            };
+
+            formatter = pkgs.alejandra;
+
+            devShells.default = import ./nix/shell.nix {
+              inherit pkgs inputs system;
+              formatter = pkgs.alejandra;
+            };
+          };
+      }
+    );
+}
diff --git a/nix/shell.nix b/nix/shell.nix
new file mode 100644
index 00000000000..ab08ee374c3
--- /dev/null
+++ b/nix/shell.nix
@@ -0,0 +1,81 @@
+{
+  pkgs,
+  inputs,
+  system,
+  formatter ? pkgs.alejandra,
+  ...
+}:
+let
+  isLinux = pkgs.stdenv.isLinux;
+  pinnedJDK = pkgs.jdk21_headless;
+
+  androidCustomPackage = inputs.android-nixpkgs.sdk.${system} (
+    sdkPkgs: with sdkPkgs; [
+      cmdline-tools-latest
+      platform-tools
+      build-tools-36-0-0
+      platforms-android-36
+      emulator
+      system-images-android-36-google-apis-playstore-x86-64
+    ]
+  );
+
+  androidEmulator = pkgs.androidenv.emulateApp {
+    name = "emulator";
+    platformVersion = "36";
+    abiVersion = "x86_64";
+    systemImageType = "google_apis_playstore";
+    configOptions = {
+      "hw.gpu.enabled" = "yes";
+      "hw.gpu.mode" = "swiftshader_indirect";
+      "hw.keyboard" = "yes";
+    };
+  };
+
+  androidEmulatorNoGPU = pkgs.androidenv.emulateApp {
+    name = "emulator";
+    platformVersion = "36";
+    abiVersion = "x86_64";
+    systemImageType = "google_apis_playstore";
+    configOptions = {
+      "hw.gpu.enabled" = "no";
+      "hw.keyboard" = "yes";
+    };
+  };
+in
+pkgs.mkShell {
+  packages = [
+    pinnedJDK
+    androidCustomPackage
+    pkgs.ktlint
+    pkgs.git
+    pkgs.coreutils
+    formatter
+  ]
+  ++ pkgs.lib.optionals isLinux [
+    (pkgs.writeScriptBin "android-emulator" ''
+      ${androidEmulator}/bin/run-test-emulator
+    '')
+    (pkgs.writeScriptBin "android-emulator-no-gpu" ''
+      ${androidEmulatorNoGPU}/bin/run-test-emulator
+    '')
+  ];
+
+  env = {
+    ANDROID_HOME = "${androidCustomPackage}/share/android-sdk";
+    ANDROID_SDK_ROOT = "${androidCustomPackage}/share/android-sdk";
+    JAVA_HOME = pinnedJDK.home;
+    GRADLE_OPTS = "-Dorg.gradle.project.android.aapt2FromMavenOverride=${androidCustomPackage}/share/android-sdk/build-tools/36.0.0/aapt2";
+  };
+
+  shellHook = ''
+    echo "---------------------------------------------------------------------------------------------------"
+    echo " Uchar Element X Android dev shell."
+    echo " JDK:           $(java -version 2>&1 | head -1)"
+    echo " ANDROID_HOME:  $ANDROID_HOME"
+    ${pkgs.lib.optionalString isLinux ''
+      echo " Emulator:      run 'android-emulator' else 'android-emulator-no-gpu'"
+    ''}
+    echo "---------------------------------------------------------------------------------------------------"
+  '';
+}