diff --git a/packages/next-utils/package.json b/packages/next-utils/package.json
index a86c574..c8a7e27 100644
--- a/packages/next-utils/package.json
+++ b/packages/next-utils/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@mintel/next-utils",
-  "version": "1.7.13",
+  "version": "1.7.14",
   "publishConfig": {
     "access": "public",
     "registry": "https://npm.infra.mintel.me"
diff --git a/packages/next-utils/src/env.ts b/packages/next-utils/src/env.ts
index 0f2a0fe..e609a7a 100644
--- a/packages/next-utils/src/env.ts
+++ b/packages/next-utils/src/env.ts
@@ -50,17 +50,45 @@ export const mintelEnvSchema = {
   INTERNAL_DIRECTUS_URL: z.string().url().optional(),
 };
 
+/**
+ * Standard Mintel refinements for environment variables.
+ * Enforces mandatory requirements for non-development environments.
+ */
+export const withMintelRefinements = <T extends z.ZodTypeAny>(schema: T) => {
+  return schema.superRefine((data: any, ctx) => {
+    const target = data.TARGET || data.NEXT_PUBLIC_TARGET || "development";
+
+    // Strict validation for non-development environments
+    if (target !== "development") {
+      if (!data.MAIL_HOST) {
+        ctx.addIssue({
+          code: z.ZodIssueCode.custom,
+          message: "MAIL_HOST is required in non-development environments",
+          path: ["MAIL_HOST"],
+        });
+      }
+    }
+  });
+};
+
 export type MintelEnv<T extends z.ZodRawShape = Record<string, never>> =
-  z.infer<z.ZodObject<typeof mintelEnvSchema & T>>;
+  z.infer<
+    ReturnType<
+      typeof withMintelRefinements<z.ZodObject<typeof mintelEnvSchema & T>>
+    >
+  >;
 
 export function validateMintelEnv<
   T extends z.ZodRawShape = Record<string, never>,
 >(schemaExtension: T = {} as T): MintelEnv<T> {
-  const fullSchema = z.object(mintelEnvSchema).extend(schemaExtension);
+  const fullSchema = withMintelRefinements(
+    z.object(mintelEnvSchema).extend(schemaExtension),
+  );
 
   const isBuildTime =
     process.env.NEXT_PHASE === "phase-production-build" ||
-    process.env.SKIP_ENV_VALIDATION === "true";
+    process.env.SKIP_ENV_VALIDATION === "true" ||
+    process.env.SKIP_RUNTIME_ENV_VALIDATION === "true";
 
   const result = fullSchema.safeParse(process.env);
 
@@ -80,5 +108,5 @@ export function validateMintelEnv<
     throw new Error("Invalid environment variables");
   }
 
-  return result.data;
+  return result.data as MintelEnv<T>;
 }