diff --git a/.bazelignore b/.bazelignore
new file mode 100644
index 000000000..92b27930b
--- /dev/null
+++ b/.bazelignore
@@ -0,0 +1 @@
+.direnv
diff --git a/.gitignore b/.gitignore
index 319b3c199..7f16a7411 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,15 @@
 #
 # The following files will be ignored by git.
 
+# Misc
+
+/.direnv
+/.envrc
+
+# Bazel
+bazel-*
+MODULE.bazel.lock
+
 # Normal editor rules
 *.swp
 *~
@@ -115,3 +124,4 @@ dep
 
 # Check output
 /check.vvp
+
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 000000000..879c5ea21
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,164 @@
+{
+  description = "fpga-assembler";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/2c8d3f48d33929642c1c12cd243df4cc7d2ce434";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      flake-utils,
+    }@inputs:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+        };
+        common = with pkgs; {
+          bazel = bazel_7;
+          jdk = jdk;
+        };
+      in
+      {
+        devShells.default =
+          let
+            # There is too much volatility between even micro-versions of
+            # newer clang-format. Use slightly older version for now.
+            clang_for_formatting = pkgs.llvmPackages_17.clang-tools;
+
+            # clang tidy: use latest.
+            clang_for_tidy = pkgs.llvmPackages_18.clang-tools;
+          in
+          with pkgs;
+          pkgs.mkShell {
+            packages = with pkgs; [
+              git
+              common.bazel
+              common.jdk
+              bash
+              gdb
+
+              # For clang-tidy and clang-format.
+              clang_for_formatting
+              clang_for_tidy
+
+              # For buildifier, buildozer.
+              bazel-buildtools
+              bant
+
+              # Profiling and sanitizers.
+              linuxPackages_latest.perf
+              pprof
+              perf_data_converter
+              valgrind
+
+              # FPGA utils.
+              openfpgaloader
+            ];
+
+            CLANG_TIDY = "${clang_for_tidy}/bin/clang-tidy";
+            CLANG_FORMAT = "${clang_for_formatting}/bin/clang-format";
+
+            shellHook = ''
+              exec bash
+            '';
+          };
+
+        # Package fpga-assembler.
+        packages.default =
+          (pkgs.callPackage (
+            {
+              buildBazelPackage,
+              stdenv,
+              fetchFromGitHub,
+              lib,
+              nix-gitignore,
+            }:
+            let
+              system = stdenv.hostPlatform.system;
+              registry = fetchFromGitHub {
+                owner = "bazelbuild";
+                repo = "bazel-central-registry";
+                rev = "63f3af762b2fdd7acaa7987856cd3ac314eaea09";
+                hash = "sha256-ugNzoP0gdrhl9vH1TRdwoevuTsSqjitXnAoMSSTlCgI=";
+              };
+            in
+            buildBazelPackage {
+              pname = "fpga-as";
+
+              version = "0.0.1";
+
+              src = nix-gitignore.gitignoreSourcePure [ ] ./.;
+
+              bazelFlags = [
+                "--registry"
+                "file://${registry}"
+              ];
+
+              postPatch = ''
+                patchShebangs scripts/create-workspace-status.sh
+              '';
+
+              fetchAttrs = {
+                hash =
+                  {
+                    aarch64-linux = "sha256-E4VHjDa0qkHmKUNpTBfJi7dhMLcd1z5he+p31/XvUl8=";
+                    x86_64-linux = "sha256-hVBJB0Hsd9sXuEoNcjhTkbPl89vlZT1w39JppCD+n8Y=";
+                  }
+                  .${system} or (throw "No hash for system: ${system}");
+              };
+
+              removeRulesCC = false;
+              removeLocalConfigCc = false;
+              removeLocalConfigSh = false;
+
+              nativeBuildInputs = [
+                common.jdk
+                pkgs.git
+                pkgs.bash
+                # Convenient tool to enter into the sandbox and start debugging.
+                pkgs.breakpointHook
+              ];
+
+              bazel = common.bazel;
+
+              bazelBuildFlags = [ "-c opt" ];
+              bazelTestTargets = [ "//..." ];
+              bazelTargets = [ "//fpga:fpga-as" ];
+
+              buildAttrs = {
+                installPhase = ''
+                  install -D --strip bazel-bin/fpga/fpga-as "$out/bin/fpga-as"
+                '';
+              };
+
+              meta = {
+                description = "Tool to convert FASM to FPGA bitstream.";
+                homepage = "https://github.com/lromor/fpga-assembler";
+                license = lib.licenses.asl20;
+                platforms = lib.platforms.linux;
+              };
+            }
+          ) { }).overrideAttrs
+            (
+              final: prev: {
+                # Fixup the deps so they always contain correrct
+                # shebangs paths pointing to the store.
+                deps = prev.deps.overrideAttrs (
+                  final: prev: {
+                    installPhase =
+                      ''
+                        patchShebangs $bazelOut/external
+                      ''
+                      + prev.installPhase;
+                  }
+                );
+              }
+            );
+      }
+    );
+}