diff --git a/devenv/default.nix b/devenv/default.nix
index 0ce66700..eaa60df8 100644
--- a/devenv/default.nix
+++ b/devenv/default.nix
@@ -113,6 +113,9 @@ in {
     agenix
     age-plugin-yubikey
     alejandra
+    fennel
+    fennel-ls
+    fnlfmt
     hcloud
     installTestVM
     just
diff --git a/flake.lock b/flake.lock
index 3d47b7ee..9b557a44 100644
--- a/flake.lock
+++ b/flake.lock
@@ -206,6 +206,23 @@
         "type": "github"
       }
     },
+    "fennel-tree-sitter": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1706884626,
+        "narHash": "sha256-BdhgDS+yJ/DUYJknVksLSNHvei+MOkqVW7gp6AffKhU=",
+        "owner": "TravonteD",
+        "repo": "tree-sitter-fennel",
+        "rev": "15e4f8c417281768db17080c4447297f8ff5343a",
+        "type": "github"
+      },
+      "original": {
+        "owner": "TravonteD",
+        "ref": "1.1.0",
+        "repo": "tree-sitter-fennel",
+        "type": "github"
+      }
+    },
     "flake-compat": {
       "flake": false,
       "locked": {
@@ -430,6 +447,35 @@
         "type": "github"
       }
     },
+    "helix-editor": {
+      "inputs": {
+        "crane": [
+          "crane"
+        ],
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "rust-overlay": [
+          "rust-overlay"
+        ]
+      },
+      "locked": {
+        "lastModified": 1725976743,
+        "narHash": "sha256-pLQQbiC9uO4lF58fAnlcDxlbsBB1XFWswsU1oZOIVqU=",
+        "owner": "helix-editor",
+        "repo": "helix",
+        "rev": "237cbe4bca46eed52efed39ed75eb44aaccbdde3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "helix-editor",
+        "repo": "helix",
+        "type": "github"
+      }
+    },
     "hetzner-csi-driver": {
       "flake": false,
       "locked": {
@@ -992,10 +1038,12 @@
         "devenv": "devenv",
         "disko": "disko",
         "fenix": "fenix",
+        "fennel-tree-sitter": "fennel-tree-sitter",
         "flake-compat": "flake-compat",
         "flake-parts": "flake-parts_2",
         "flake-utils": "flake-utils_2",
         "fluxcd-install": "fluxcd-install",
+        "helix-editor": "helix-editor",
         "hetzner-csi-driver": "hetzner-csi-driver",
         "home-manager": "home-manager",
         "impermanence": "impermanence",
diff --git a/flake.nix b/flake.nix
index eb5fa127..6d753569 100644
--- a/flake.nix
+++ b/flake.nix
@@ -4,18 +4,19 @@
   nixConfig = {
     extra-experimental-features = "nix-command flakes";
     extra-substituters = [
-      "https://nix-community.cachix.org"
-      "https://insane.cachix.org"
+      "https://cache.flox.dev"
       "https://cachix.cachix.org"
       "https://hyprland.cachix.org"
-      "https://cache.flox.dev"
+      "https://insane.cachix.org"
+      "https://nix-community.cachix.org"
     ];
+
     extra-trusted-public-keys = [
-      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
-      "insane.cachix.org-1:cLCCoYQKkmEb/M88UIssfg2FiSDUL4PUjYj9tdo4P8o="
       "cachix.cachix.org-1:eWNHQldwUO7G2VkjpnjDbWwy4KQ/HNxht7H4SSoMckM="
-      "hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc="
       "flox-cache-public-1:7F4OyH7ZCnFhcze3fJdfyXYLQw/aV7GEed86nQ7IsOs="
+      "hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc="
+      "insane.cachix.org-1:cLCCoYQKkmEb/M88UIssfg2FiSDUL4PUjYj9tdo4P8o="
+      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
     ];
   };
 
@@ -45,6 +46,8 @@
     devenv.url = "github:cachix/devenv";
     disko.inputs.nixpkgs.follows = "nixpkgs";
     disko.url = "github:nix-community/disko";
+    fennel-tree-sitter.flake = false;
+    fennel-tree-sitter.url = "github:TravonteD/tree-sitter-fennel/1.1.0";
     fenix.inputs.nixpkgs.follows = "nixpkgs";
     fenix.url = "github:nix-community/fenix";
     flake-compat.flake = false;
@@ -53,6 +56,11 @@
     flake-utils.inputs.systems.follows = "systems";
     fluxcd-install.flake = false;
     fluxcd-install.url = "https://github.com/fluxcd/flux2/releases/download/v2.3.0/install.yaml"; # gh-release-update
+    helix-editor.url = "github:helix-editor/helix";
+    helix-editor.inputs.nixpkgs.follows = "nixpkgs";
+    helix-editor.inputs.flake-utils.follows = "flake-utils";
+    helix-editor.inputs.rust-overlay.follows = "rust-overlay";
+    helix-editor.inputs.crane.follows = "crane";
     hetzner-csi-driver.flake = false;
     hetzner-csi-driver.url = "https://raw.githubusercontent.com/hetznercloud/csi-driver/v2.9.0/deploy/kubernetes/hcloud-csi.yml"; # gh-release-update
     home-manager.inputs.nixpkgs.follows = "nixpkgs";
diff --git a/flake/packages.nix b/flake/packages.nix
index f996ef2e..0eef5de4 100644
--- a/flake/packages.nix
+++ b/flake/packages.nix
@@ -122,6 +122,57 @@
             boot.kernelPackages = lib.mkForce pkgs.linuxPackages_latest;
           }
         ];
+        helix-latest = inputs.helix-editor.packages.${system}.default.override {
+          grammarOverlays = [
+            (final: prev: {
+              fennel = pkgs.stdenv.mkDerivation {
+                pname = "helix-tree-sitter-fennel";
+                version = inputs.fennel-tree-sitter.rev;
+                src = inputs.fennel-tree-sitter;
+                sourceRoot = "source";
+                dontConfigure = true;
+                FLAGS = [
+                  "-Isrc"
+                  "-g"
+                  "-O3"
+                  "-fPIC"
+                  "-fno-exceptions"
+                  "-Wl,-z,relro,-z,now"
+                ];
+                NAME = "fennel";
+                buildPhase = ''
+                  runHook preBuild
+
+                  if [[ -e src/scanner.cc ]]; then
+                    $CXX -c src/scanner.cc -o scanner.o $FLAGS
+                  elif [[ -e src/scanner.c ]]; then
+                    $CC -c src/scanner.c -o scanner.o $FLAGS
+                  fi
+
+                  $CC -c src/parser.c -o parser.o $FLAGS
+                  $CXX -shared -o $NAME.so *.o
+
+                  ls -al
+
+                  runHook postBuild
+                '';
+                installPhase = ''
+                  runHook preInstall
+                  mkdir $out
+                  mv $NAME.so $out/
+                  runHook postInstall
+                '';
+
+                # Strip failed on darwin: strip: error: symbols referenced by indirect symbol table entries that can't be stripped
+                fixupPhase = lib.optionalString pkgs.stdenv.isLinux ''
+                  runHook preFixup
+                  $STRIP $out/$NAME.so
+                  runHook postFixup
+                '';
+              };
+            })
+          ];
+        };
         zjstatus = inputs.zjstatus.packages.${system}.default;
         zwift = inputs.zwift.packages.${system}.default;
         persway = inputs.persway.packages.${system}.default;
diff --git a/users/profiles/helix.nix b/users/profiles/helix.nix
index d20a2898..289c8bcf 100644
--- a/users/profiles/helix.nix
+++ b/users/profiles/helix.nix
@@ -15,10 +15,88 @@
         OPENROUTER_API_KEY="$(cat /run/agenix/openrouter-lsp-ai)"
         export OPENROUTER_API_KEY
       fi
-      exec ${pkgs.helix}/bin/hx "''$@"
+      exec ${pkgs.helix-latest}/bin/hx "''$@"
     '';
   };
 in {
+  xdg.configFile."helix/runtime/queries/fennel/highlights.scm".source = pkgs.writeText "fennel-highlights.scm" ''
+    (comment) @comment
+
+    [ "(" ")" "{" "}" "[" "]" ] @punctuation.bracket
+
+    [ ":" ":until" "&" "&as" "?" ] @punctuation.special
+
+    (nil) @constant.builtin
+    (vararg) @punctuation.special
+
+    (boolean) @constant.builtin.boolean
+    (number) @constant.numeric
+
+    (string) @string
+    (escape_sequence) @constant.character.escape
+
+
+    ((symbol) @variable.builtin
+     (#match? @variable.builtin "^[$]"))
+
+    (binding) @symbol
+
+    [ "fn" "lambda" "hashfn" "#" ] @keyword.function
+
+    (fn name: [
+      (symbol) @function
+      (multi_symbol (symbol) @function .)
+    ])
+
+    (lambda name: [
+      (symbol) @function
+      (multi_symbol (symbol) @function .)
+    ])
+
+    (multi_symbol
+      "." @punctuation.delimiter
+      (symbol) @variable.other.member)
+
+    (multi_symbol_method
+      ":" @punctuation.delimiter
+      (symbol) @function.method .)
+
+    [ "for" "each" ] @keyword.control.repeat
+    ((symbol) @keyword.control.repeat
+     (#eq? @keyword.control.repeat
+      "while"))
+
+    [ "match" ] @keyword.control.conditional
+    ((symbol) @keyword.control.conditional
+     (#match? @keyword.control.conditional "^(if|when)$"))
+
+    [ "global" "local" "let" "set" "var" "where" "or" ] @keyword
+    ((symbol) @keyword
+     (#match? @keyword
+      "^(comment|do|doc|eval-compiler|lua|macros|quote|tset|values)$"))
+
+    ((symbol) @keyword.control.import
+     (#match? @keyword.control.import
+      "^(require|require-macros|import-macros|include)$"))
+
+    [ "collect" "icollect" "accumulate" ] @function.macro
+    ((symbol) @function.macro
+     (#match? @function.macro
+      "^(->|->>|-\\?>|-\\?>>|\\?\\.|doto|macro|macrodebug|partial|pick-args|pick-values|with-open)$"))
+
+    ; Lua builtins
+    ((symbol) @constant.builtin
+     (#match? @constant.builtin
+      "^(arg|_ENV|_G|_VERSION)$"))
+
+    ((symbol) @function.builtin
+     (#match? @function.builtin
+      "^(assert|collectgarbage|dofile|error|getmetatable|ipairs|load|loadfile|loadstring|module|next|pairs|pcall|print|rawequal|rawget|rawlen|rawset|require|select|setfenv|setmetatable|tonumber|tostring|type|unpack|warn|xpcall)$"))
+
+    (list . (symbol) @function)
+    (list . (multi_symbol (symbol) @function .))
+    (symbol) @variable
+  '';
   programs.helix = {
     enable = true;
     package = helix-ai;
@@ -80,6 +158,9 @@ in {
     };
     languages = {
       language-server = {
+        fennel-ls = {
+          command = "fennel-ls";
+        };
         lsp-ai = {
           command = "lsp-ai";
           config.memory.file_store = {};
@@ -357,6 +438,26 @@ in {
           name = "yaml";
           language-servers = ["yaml-language-server" "lsp-ai"];
         }
+        {
+          name = "fennel";
+          scope = "source.fnl";
+          injection-regex = "(fennel|fnl)";
+          file-types = ["fnl"];
+          shebangs = ["fennel"];
+          roots = [];
+          comment-token = ";";
+          indent = {
+            tab-width = 2;
+            unit = "  ";
+          };
+          formatter = {
+            command = "fnlfmt";
+            args = ["-"];
+          };
+          language-servers = ["fennel-ls" "lsp-ai"];
+          grammar = "fennel";
+          auto-format = true;
+        }
         {
           name = "lua";
           formatter = {