diff --git a/.envrc b/.envrc
deleted file mode 100644
index 1d953f4b..00000000
--- a/.envrc
+++ /dev/null
@@ -1 +0,0 @@
-use nix
diff --git a/.envrc.developer.template b/.envrc.developer.template
new file mode 100644
index 00000000..e8e67adb
--- /dev/null
+++ b/.envrc.developer.template
@@ -0,0 +1 @@
+use flake . --override-input neovim-src /path/to/neovim
diff --git a/.envrc.minimal.template b/.envrc.minimal.template
new file mode 100644
index 00000000..5f0fc3f2
--- /dev/null
+++ b/.envrc.minimal.template
@@ -0,0 +1 @@
+use flake .#minimal
diff --git a/.gitignore b/.gitignore
index 45f52016..9f0ce67a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,11 @@
-# nix
+# direnv
+/.direnv
+/.envrc
+
+# neovim-developer
+/runtime/
 
+# nix
 result
 result-*
 .pre-commit-config.yaml
diff --git a/flake-compat.nix b/flake-compat.nix
index 873ece49..0205bc89 100644
--- a/flake-compat.nix
+++ b/flake-compat.nix
@@ -3,11 +3,12 @@
     let
       lock = builtins.fromJSON (builtins.readFile ./flake.lock);
     in
-    fetchTarball {
-      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
-      sha256 = lock.nodes.flake-compat.locked.narHash;
-    }
+      fetchTarball {
+        url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+        sha256 = lock.nodes.flake-compat.locked.narHash;
+      }
   )
   {
     src = ./.;
-  }).defaultNix
+  })
+.defaultNix
diff --git a/flake.lock b/flake.lock
index c241cb71..097e1cb0 100644
--- a/flake.lock
+++ b/flake.lock
@@ -16,6 +16,22 @@
         "type": "github"
       }
     },
+    "flake-compat_2": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1696426674,
+        "narHash": "sha256-kvjfFW7WAETZlt09AgDn1MrtKzP7t90Vf7vypd3OL1U=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "0f9255e01c2351cc7d116c072cb317785dd33b33",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-parts": {
       "inputs": {
         "nixpkgs-lib": [
@@ -23,11 +39,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1714641030,
-        "narHash": "sha256-yzcRNDoyVP7+SCNX0wmuDju1NUCt8Dz9+lyUXEI0dbI=",
+        "lastModified": 1715865404,
+        "narHash": "sha256-/GJvTdTpuDjNn84j82cU6bXztE0MSkdnTWClUCRub78=",
         "owner": "hercules-ci",
         "repo": "flake-parts",
-        "rev": "e5d10a24b66c3ea8f150e47dfdb0416ab7c3390e",
+        "rev": "8dc45382d5206bd292f9c2768b8058a8fd8311d9",
         "type": "github"
       },
       "original": {
@@ -56,21 +72,24 @@
         "type": "indirect"
       }
     },
-    "flake-utils": {
+    "gitignore": {
       "inputs": {
-        "systems": "systems"
+        "nixpkgs": [
+          "pre-commit-hooks",
+          "nixpkgs"
+        ]
       },
       "locked": {
-        "lastModified": 1710146030,
-        "narHash": "sha256-SZ5L6eA7HJ/nmkzGG7/ISclqe6oZdOZTNoesiInkXPQ=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "b1d9ab70662946ef0850d488da1c9019f3a9752a",
+        "lastModified": 1709087332,
+        "narHash": "sha256-HG2cCnktfHsKV0s4XW83gU3F57gaTljL9KNSuG6bnQs=",
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
+        "rev": "637db329424fd7e46cf4185293b9cc8c88c95394",
         "type": "github"
       },
       "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
+        "owner": "hercules-ci",
+        "repo": "gitignore.nix",
         "type": "github"
       }
     },
@@ -95,24 +114,17 @@
         "type": "github"
       }
     },
-    "neovim-flake": {
-      "inputs": {
-        "flake-utils": "flake-utils",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
+    "neovim-src": {
+      "flake": false,
       "locked": {
-        "dir": "contrib",
-        "lastModified": 1715815279,
-        "narHash": "sha256-Pf7ZlqPnr195NZb5ADzMVsXurPMjRZ+JMXf6JxvXArE=",
+        "lastModified": 1716501420,
+        "narHash": "sha256-VO9RCUNwiU627oVjR5gfsyz8z6VHkuW2VFT53xth1ig=",
         "owner": "neovim",
         "repo": "neovim",
-        "rev": "9ca81b025990911c2a0dbda92af39ba84983bac3",
+        "rev": "e7859d2ad504a3e3cae1d540d5fd4f9b560d154a",
         "type": "github"
       },
       "original": {
-        "dir": "contrib",
         "owner": "neovim",
         "repo": "neovim",
         "type": "github"
@@ -120,43 +132,54 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1715774670,
-        "narHash": "sha256-iJYnKMtLi5u6hZhJm94cRNSDG5Rz6ZzIkGbhPFtDRm0=",
+        "lastModified": 1716451822,
+        "narHash": "sha256-0lT5RVelqN+dgXWWneXvV5ufSksW0r0TDQi8O6U2+o8=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "b3fcfcfabd01b947a1e4f36622bbffa3985bdac6",
+        "rev": "3305b2b25e4ae4baee872346eae133cf6f611783",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
         "repo": "nixpkgs",
+        "rev": "3305b2b25e4ae4baee872346eae133cf6f611783",
         "type": "github"
       }
     },
-    "root": {
+    "pre-commit-hooks": {
       "inputs": {
-        "flake-compat": "flake-compat",
-        "flake-parts": "flake-parts",
-        "hercules-ci-effects": "hercules-ci-effects",
-        "neovim-flake": "neovim-flake",
-        "nixpkgs": "nixpkgs"
-      }
-    },
-    "systems": {
+        "flake-compat": "flake-compat_2",
+        "gitignore": "gitignore",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "nixpkgs-stable": [
+          "nixpkgs"
+        ]
+      },
       "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
-        "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "lastModified": 1716213921,
+        "narHash": "sha256-xrsYFST8ij4QWaV6HEokCUNIZLjjLP1bYC60K8XiBVA=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "0e8fcc54b842ad8428c9e705cb5994eaf05c26a0",
         "type": "github"
       },
       "original": {
-        "owner": "nix-systems",
-        "repo": "default",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
         "type": "github"
       }
+    },
+    "root": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "flake-parts": "flake-parts",
+        "hercules-ci-effects": "hercules-ci-effects",
+        "neovim-src": "neovim-src",
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks"
+      }
     }
   },
   "root": "root",
diff --git a/flake.nix b/flake.nix
index 62191a4a..c3f2a702 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,15 +2,34 @@
   description = "Neovim flake";
 
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
-    flake-parts = { url = "github:hercules-ci/flake-parts"; inputs.nixpkgs-lib.follows = "nixpkgs"; };
-    hercules-ci-effects = { url = "github:hercules-ci/hercules-ci-effects"; inputs.nixpkgs.follows = "nixpkgs"; };
-    flake-compat = { url = "github:edolstra/flake-compat"; flake = false; };
-    neovim-flake = { url = "github:neovim/neovim?dir=contrib"; inputs.nixpkgs.follows = "nixpkgs"; };
+    nixpkgs.url = "github:NixOS/nixpkgs/3305b2b25e4ae4baee872346eae133cf6f611783";
+    flake-parts = {
+      url = "github:hercules-ci/flake-parts";
+      inputs.nixpkgs-lib.follows = "nixpkgs";
+    };
+    hercules-ci-effects = {
+      url = "github:hercules-ci/hercules-ci-effects";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    flake-compat = {
+      url = "github:edolstra/flake-compat";
+      flake = false;
+    };
+    neovim-src = {
+      url = "github:neovim/neovim";
+      flake = false;
+    };
+    pre-commit-hooks = {
+      url = "github:cachix/pre-commit-hooks.nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.nixpkgs-stable.follows = "nixpkgs";
+    };
   };
 
   outputs = inputs:
-    inputs.flake-parts.lib.mkFlake { inherit inputs; } ({ config, ... }: {
+    inputs.flake-parts.lib.mkFlake
+    {inherit inputs;}
+    ({config, ...}: {
       systems = [
         "x86_64-linux"
         "x86_64-darwin"
@@ -19,33 +38,7 @@
       ];
 
       imports = [
-        inputs.flake-parts.flakeModules.easyOverlay
-        inputs.hercules-ci-effects.flakeModule
+        ./flake
       ];
-
-      perSystem = { inputs', system, config, lib, pkgs, ... }: {
-        packages = {
-          neovim = inputs'.neovim-flake.packages.neovim // (lib.optionalAttrs pkgs.stdenv.isDarwin { ignoreFailure = true; });
-          default = config.packages.neovim;
-        };
-        overlayAttrs = lib.genAttrs [ "neovim-unwrapped" "neovim-nightly" ] (_: config.packages.neovim);
-      };
-
-      flake = {
-        defaultPackage = inputs.nixpkgs.lib.genAttrs config.systems (system: inputs.self.packages.${system}.default);
-        overlay = inputs.self.overlays.default;
-      };
-
-      hercules-ci.flake-update = {
-        enable = true;
-        baseMerge.enable = true;
-        baseMerge.method = "rebase";
-        autoMergeMethod = "rebase";
-        # Update everynight at midnight
-        when = {
-          hour = [ 0 ];
-          minute = 0;
-        };
-      };
     });
 }
diff --git a/flake/checks.nix b/flake/checks.nix
new file mode 100644
index 00000000..6023d84a
--- /dev/null
+++ b/flake/checks.nix
@@ -0,0 +1,22 @@
+{inputs, ...}: {
+  perSystem = {
+    pkgs,
+    config,
+    ...
+  }: {
+    checks = {
+      # TODO: not working: remove ?
+      # shlint = pkgs.runCommand "shlint" {
+      #   nativeBuildInputs = [pkgs.shellcheck];
+      #   preferLocalBuild = true;
+      # } "make -C ${inputs.neovim-src} shlint > $out";
+
+      inherit
+        (config.packages)
+        neovim
+        neovim-debug
+        neovim-developer
+        ;
+    };
+  };
+}
diff --git a/flake/ci.nix b/flake/ci.nix
new file mode 100644
index 00000000..cd96ce32
--- /dev/null
+++ b/flake/ci.nix
@@ -0,0 +1,17 @@
+{inputs, ...}: {
+  imports = [
+    inputs.hercules-ci-effects.flakeModule
+  ];
+
+  hercules-ci.flake-update = {
+    enable = true;
+    baseMerge.enable = true;
+    baseMerge.method = "rebase";
+    autoMergeMethod = "rebase";
+    # Update everynight at midnight
+    when = {
+      hour = [0];
+      minute = 0;
+    };
+  };
+}
diff --git a/flake/default.nix b/flake/default.nix
new file mode 100644
index 00000000..8def5657
--- /dev/null
+++ b/flake/default.nix
@@ -0,0 +1,20 @@
+{inputs, ...}: {
+  imports = [
+    ./checks.nix
+    ./ci.nix
+    ./devshells.nix
+    ./overlays.nix
+    ./packages
+    inputs.pre-commit-hooks.flakeModule
+  ];
+
+  perSystem = {pkgs, ...}: {
+    formatter = pkgs.alejandra;
+    pre-commit.settings.hooks.alejandra.enable = true;
+
+    # Neovim uses lua 5.1 as it is the version which supports JIT
+    _module.args = {
+      lua = pkgs.lua5_1;
+    };
+  };
+}
diff --git a/flake/devshells.nix b/flake/devshells.nix
new file mode 100644
index 00000000..d89da48e
--- /dev/null
+++ b/flake/devshells.nix
@@ -0,0 +1,50 @@
+{
+  perSystem = {
+    pkgs,
+    config,
+    lua,
+    ...
+  }: {
+    devShells = {
+      default = pkgs.mkShell {
+        name = "neovim-developer-shell";
+        inputsFrom = [
+          config.devShells.minimal
+          config.packages.neovim-developer
+        ];
+        shellHook = ''
+          ${config.packages.neovim-developer.shellHook or ""}
+          export ASAN_SYMBOLIZER_PATH=${pkgs.llvm_18}/bin/llvm-symbolizer
+          export NVIM_PYTHON_LOG_LEVEL=DEBUG
+          export NVIM_LOG_FILE=/tmp/nvim.log
+
+          # ASAN_OPTIONS=detect_leaks=1
+          export ASAN_OPTIONS="log_path=./test.log:abort_on_error=1"
+
+          # for treesitter functionaltests
+          mkdir -p runtime/parser
+          cp -f ${pkgs.vimPlugins.nvim-treesitter.builtGrammars.c}/parser runtime/parser/c.so
+        '';
+      };
+
+      # Provide a devshell that can be used strictly for developing this flake.
+      minimal = pkgs.mkShell.override {inherit (pkgs.llvmPackages_latest) stdenv;} {
+        name = "neovim-minimal-shell";
+        inputsFrom = [
+          config.packages.default
+        ];
+        packages = with pkgs; [
+          (python3.withPackages (ps: [ps.msgpack]))
+          include-what-you-use
+          jq
+          lua-language-server
+          lua.pkgs.luacheck
+          shellcheck
+        ];
+        shellHook = ''
+          export VIMRUNTIME=
+        '';
+      };
+    };
+  };
+}
diff --git a/flake/overlays.nix b/flake/overlays.nix
new file mode 100644
index 00000000..83b70105
--- /dev/null
+++ b/flake/overlays.nix
@@ -0,0 +1,23 @@
+{inputs, ...}: {
+  imports = [
+    inputs.flake-parts.flakeModules.easyOverlay
+  ];
+
+  perSystem = {
+    inputs',
+    system,
+    config,
+    lib,
+    pkgs,
+    ...
+  }: {
+    overlayAttrs = {
+      inherit
+        (config.packages)
+        neovim
+        neovim-debug
+        neovim-developer
+        ;
+    };
+  };
+}
diff --git a/flake/packages/default.nix b/flake/packages/default.nix
new file mode 100644
index 00000000..992864ad
--- /dev/null
+++ b/flake/packages/default.nix
@@ -0,0 +1,31 @@
+{inputs, ...}: {
+  perSystem = {
+    inputs',
+    system,
+    config,
+    lib,
+    pkgs,
+    lua,
+    ...
+  }: {
+    packages = {
+      default = config.packages.neovim;
+
+      neovim = import ./neovim.nix {
+        inherit (inputs) neovim-src;
+        inherit lib pkgs;
+      };
+
+      neovim-debug = import ./neovim-debug.nix {
+        inherit (config.packages) neovim;
+        inherit pkgs;
+      };
+
+      neovim-developer = import ./neovim-developer.nix {
+        inherit (config.packages) neovim-debug;
+        inherit (inputs) neovim-src;
+        inherit lib pkgs lua;
+      };
+    };
+  };
+}
diff --git a/flake/packages/neovim-debug.nix b/flake/packages/neovim-debug.nix
new file mode 100644
index 00000000..f3fb0aab
--- /dev/null
+++ b/flake/packages/neovim-debug.nix
@@ -0,0 +1,20 @@
+{
+  neovim,
+  pkgs,
+  ...
+}:
+(neovim.override {
+  stdenv =
+    if pkgs.stdenv.isLinux
+    then pkgs.llvmPackages_latest.stdenv
+    else pkgs.stdenv;
+  lua = pkgs.luajit;
+})
+.overrideAttrs (
+  oa: {
+    dontStrip = true;
+    NIX_CFLAGES_COMPILE = " -ggdb -Og";
+    cmakeBuildType = "Debug";
+    disallowedReferences = [];
+  }
+)
diff --git a/flake/packages/neovim-developer.nix b/flake/packages/neovim-developer.nix
new file mode 100644
index 00000000..a10bf5be
--- /dev/null
+++ b/flake/packages/neovim-developer.nix
@@ -0,0 +1,25 @@
+{
+  neovim-debug,
+  pkgs,
+  lua,
+  lib,
+  neovim-src,
+  ...
+}:
+neovim-debug.overrideAttrs (oa: {
+  cmakeFlagsArray =
+    oa.cmakeFlagsArray
+    ++ [
+      "-DLUACHECK_PRG=${lua.pkgs.luacheck}/bin/luacheck"
+      "-DENABLE_LTO=OFF"
+    ]
+    ++ lib.optionals pkgs.stdenv.isLinux [
+      # https://github.com/google/sanitizers/wiki/AddressSanitizerFlags
+      # https://clang.llvm.org/docs/AddressSanitizer.html#symbolizing-the-reports
+      "-DENABLE_ASAN_UBSAN=ON"
+    ];
+  doCheck = pkgs.stdenv.isLinux;
+  shellHook = ''
+    export VIMRUNTIME=${neovim-src}/runtime
+  '';
+})
diff --git a/flake/packages/neovim.nix b/flake/packages/neovim.nix
new file mode 100644
index 00000000..20040aef
--- /dev/null
+++ b/flake/packages/neovim.nix
@@ -0,0 +1,91 @@
+{
+  neovim-src,
+  lib,
+  pkgs,
+  ...
+}: let
+  src = pkgs.fetchFromGitHub {
+    owner = "neovim";
+    repo = "neovim";
+    inherit (neovim-src) rev;
+    hash = neovim-src.narHash;
+  };
+
+  deps = lib.pipe "${src}/cmake.deps/deps.txt" [
+    builtins.readFile
+    (lib.splitString "\n")
+    (map (builtins.match "([A-Z0-0_]+)_(URL|SHA256)[[:space:]]+([^[:space:]]+)[[:space:]]*"))
+    (lib.remove null)
+    (lib.flip builtins.foldl' {}
+      (acc: matches: let
+        name = lib.toLower (builtins.elemAt matches 0);
+        key = lib.toLower (builtins.elemAt matches 1);
+        value = lib.toLower (builtins.elemAt matches 2);
+      in
+        acc
+        // {
+          ${name} =
+            acc.${name}
+            or {}
+            // {
+              ${key} = value;
+            };
+        }))
+    (builtins.mapAttrs (lib.const pkgs.fetchurl))
+  ];
+in
+  (pkgs.neovim-unwrapped.override {
+    gettext = pkgs.gettext.overrideAttrs (_: {
+      src = deps.gettext;
+    });
+    libiconv = pkgs.libiconv.overrideAttrs (_: {
+      src = deps.libiconv;
+    });
+    libuv = pkgs.libuv.overrideAttrs (_: {
+      src = deps.libuv;
+    });
+    libvterm-neovim = pkgs.libvterm-neovim.overrideAttrs (_: {
+      src = deps.libvterm;
+    });
+    msgpack-c = pkgs.msgpack-c.overrideAttrs (_: {
+      src = deps.msgpack;
+    });
+    tree-sitter = pkgs.tree-sitter.override (_: {
+      rustPlatform =
+        pkgs.rustPlatform
+        // {
+          buildRustPackage = args:
+            pkgs.rustPlatform.buildRustPackage (args
+              // {
+                src = deps.treesitter;
+                cargoHash = "sha256-U2YXpNwtaSSEftswI0p0+npDJqOq5GqxEUlOPRlJGmQ=";
+              });
+        };
+    });
+    treesitter-parsers = let
+      grammars = lib.filterAttrs (name: _: lib.hasPrefix "treesitter_" name) deps;
+      parsers =
+        lib.mapAttrs'
+        (name: value: lib.nameValuePair (lib.removePrefix "treesitter_" name) {src = value;})
+        grammars;
+    in
+      parsers
+      // {
+        markdown = parsers.markdown // {location = "tree-sitter-markdown";};
+        # TODO useless at some point (has been fixed in nixpkgs master)
+        markdown_inline =
+          parsers.markdown
+          // {
+            language = "markdown_inline";
+            location = "tree-sitter-markdown-inline";
+          };
+      };
+  })
+  .overrideAttrs (oa: {
+    version = "nightly";
+    inherit src;
+    preConfigure = ''
+      ${oa.preConfigure}
+      sed -i cmake.config/versiondef.h.in -e 's/@NVIM_VERSION_PRERELEASE@/-dev+${neovim-src.shortRev or "dirty"}/'
+    '';
+  })