diff --git a/docs/src/reference/options.md b/docs/src/reference/options.md
index 3cb3f615db..69ed5dbfd0 100644
--- a/docs/src/reference/options.md
+++ b/docs/src/reference/options.md
@@ -3040,6 +3040,122 @@ null or YAML 1.1 value
 
 
 
+## git.conflictStyle
+
+
+
+Git conflict style (e.g., ‘merge’, ‘diff3’, ‘zdiff3’).
+
+
+
+*Type:*
+null or string
+
+
+
+*Default:*
+` null `
+
+*Declared by:*
+ - [https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix](https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix)
+
+
+
+## git.diffTool
+
+
+
+Git diff tool to use (e.g., ‘difftastic’, ‘vimdiff’).
+
+
+
+*Type:*
+null or string
+
+
+
+*Default:*
+` null `
+
+*Declared by:*
+ - [https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix](https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix)
+
+
+
+## git.mergeDriver
+
+
+
+Custom git merge drivers (e.g., mergiraf).
+
+
+
+*Type:*
+attribute set of (submodule)
+
+
+
+*Default:*
+` { } `
+
+*Declared by:*
+ - [https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix](https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix)
+
+
+
+## git.mergeDriver.\<name>.driver
+
+
+
+Driver command to run.
+
+
+
+*Type:*
+string
+
+*Declared by:*
+ - [https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix](https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix)
+
+
+
+## git.mergeDriver.\<name>.name
+
+
+
+Name of the merge driver.
+
+
+
+*Type:*
+string
+
+*Declared by:*
+ - [https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix](https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix)
+
+
+
+## git.mergeTool
+
+
+
+Git merge tool to use (e.g., ‘vimdiff’, ‘meld’).
+
+
+
+*Type:*
+null or string
+
+
+
+*Default:*
+` null `
+
+*Declared by:*
+ - [https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix](https://github.com/cachix/devenv/blob/main/src/modules/integrations/git.nix)
+
+
+
 ## git.root
 
 
@@ -18468,6 +18584,27 @@ package
 
 
 
+## mergiraf.enable
+
+
+
+Integrate mergiraf as git merge driver: https://mergiraf.org/
+
+
+
+*Type:*
+boolean
+
+
+
+*Default:*
+` false `
+
+*Declared by:*
+ - [https://github.com/cachix/devenv/blob/main/src/modules/integrations/mergiraf.nix](https://github.com/cachix/devenv/blob/main/src/modules/integrations/mergiraf.nix)
+
+
+
 ## name
 
 
diff --git a/src/modules/integrations/difftastic.nix b/src/modules/integrations/difftastic.nix
index b8389fa70f..4a9f99cc37 100644
--- a/src/modules/integrations/difftastic.nix
+++ b/src/modules/integrations/difftastic.nix
@@ -10,6 +10,6 @@
   config = lib.mkIf config.difftastic.enable {
     packages = [ pkgs.difftastic ];
 
-    env.GIT_EXTERNAL_DIFF = "difft";
+    git.diffTool = "difftastic";
   };
 }
diff --git a/src/modules/integrations/git.nix b/src/modules/integrations/git.nix
index ddc75ba116..755d23af2d 100644
--- a/src/modules/integrations/git.nix
+++ b/src/modules/integrations/git.nix
@@ -7,5 +7,65 @@
       description = "Git repository root path. This field is populated automatically in devenv 1.10 and newer.";
       default = null;
     };
+
+    diffTool = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      description = "Git diff tool to use (e.g., 'difftastic', 'vimdiff').";
+      default = null;
+    };
+
+    mergeTool = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      description = "Git merge tool to use (e.g., 'vimdiff', 'meld').";
+      default = null;
+    };
+
+    mergeDriver = lib.mkOption {
+      type = lib.types.attrsOf (lib.types.submodule {
+        options = {
+          name = lib.mkOption {
+            type = lib.types.str;
+            description = "Name of the merge driver.";
+          };
+          driver = lib.mkOption {
+            type = lib.types.str;
+            description = "Driver command to run.";
+          };
+        };
+      });
+      description = "Custom git merge drivers (e.g., mergiraf).";
+      default = { };
+    };
+
+    conflictStyle = lib.mkOption {
+      type = lib.types.nullOr lib.types.str;
+      description = "Git conflict style (e.g., 'merge', 'diff3', 'zdiff3').";
+      default = null;
+    };
+  };
+
+  config = lib.mkIf (config.git.diffTool != null || config.git.mergeTool != null || config.git.mergeDriver != { } || config.git.conflictStyle != null) {
+    env.GIT_CONFIG_GLOBAL = lib.concatStringsSep "\n" (
+      [ "[include]" "    path = ~/.gitconfig" ] ++
+      lib.optionals (config.git.diffTool != null) [
+        "[diff]"
+        "    tool = ${config.git.diffTool}"
+      ] ++
+      lib.optionals (config.git.conflictStyle != null) [
+        "[diff]"
+        "    conflictStyle = ${config.git.conflictStyle}"
+      ] ++
+      lib.optionals (config.git.mergeTool != null) [
+        "[merge]"
+        "    tool = ${config.git.mergeTool}"
+      ] ++
+      lib.concatMap
+        (driverName: [
+          "[merge \"${driverName}\"]"
+          "    name = ${config.git.mergeDriver.${driverName}.name}"
+          "    driver = ${config.git.mergeDriver.${driverName}.driver}"
+        ])
+        (lib.attrNames config.git.mergeDriver)
+    );
   };
 }
diff --git a/src/modules/integrations/mergiraf.nix b/src/modules/integrations/mergiraf.nix
new file mode 100644
index 0000000000..72be4e4b30
--- /dev/null
+++ b/src/modules/integrations/mergiraf.nix
@@ -0,0 +1,23 @@
+{ pkgs, lib, config, ... }:
+
+{
+  options.mergiraf.enable = lib.mkOption {
+    type = lib.types.bool;
+    default = false;
+    description = "Integrate mergiraf as git merge driver: https://mergiraf.org/";
+  };
+
+  config = lib.mkIf config.mergiraf.enable {
+    packages = [ pkgs.mergiraf ];
+
+    git = {
+      mergeTool = "mergiraf";
+      mergeDriver.mergiraf = {
+        name = "mergiraf";
+        driver = "mergiraf merge --git %O %A %B -s %S -x %X -y %Y -p %P -l %L";
+      };
+      # mergiraf requires diff3 conflict style to reconstruct the base revision
+      conflictStyle = "diff3";
+    };
+  };
+}