diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..3550a30
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/.gitignore b/.gitignore
index ea8c4bf..6abfe1b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 /target
+/.direnv
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..185f624
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,82 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1722813957,
+        "narHash": "sha256-IAoYyYnED7P8zrBFMnmp7ydaJfwTnwcnqxUElC1I26Y=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "cb9a96f23c491c081b38eab96d22fa958043c9fa",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay",
+        "utils": "utils"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1723343015,
+        "narHash": "sha256-oS8Qhpo71B/6OOsuVBFJbems7RKD/5e3TN2AdXhwMjg=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "ed4fe9af3814694d59c572649e881a6aa6eba533",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1710146030,
+        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..da1051d
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,51 @@
+{
+  description = ''
+    Language server proxy which enables sharing a single language server,
+    like rust-analyzer, between multiple LSP clients (editor windows).
+  '';
+
+  inputs = {
+    nixpkgs.url      = "github:NixOS/nixpkgs/nixos-unstable";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    utils.url        = "github:numtide/flake-utils";
+
+    rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs = { self, nixpkgs, rust-overlay, utils }:
+  utils.lib.eachDefaultSystem (system:
+    let
+      pkgs = import nixpkgs {
+        inherit system;
+        overlays = [(import rust-overlay)];
+      };
+
+      rustToolchain = pkgs.rust-bin.stable."1.80.1".minimal;
+      rustPlatform = pkgs.makeRustPlatform {
+        cargo = rustToolchain;
+        rustc = rustToolchain;
+      };
+
+      rustDev = rustToolchain.override {
+        extensions = ["rust-src" "rust-analyzer" "rust-docs" "clippy"];
+      };
+      # We want to use some unstable options in `rustfmt.toml` and
+      # unfortunately the only way to do that is use nightly rustfmt.
+      rustFmt = pkgs.rust-bin.nightly."2024-07-07".minimal.override {
+        extensions = ["rustfmt"];
+      };
+    in {
+      packages.default = rustPlatform.buildRustPackage {
+        pname = "ra-multiplex";
+        version = "0.2.5";
+        src = self;
+        cargoLock.lockFile = ./Cargo.lock;
+      };
+      devShells.default = pkgs.mkShell {
+        nativeBuildInputs = [
+          rustDev
+          rustFmt
+        ];
+      };
+    });
+}