diff --git a/src/schemas/space.json b/src/schemas/space.json
index 542f0c339..489a2bf01 100644
--- a/src/schemas/space.json
+++ b/src/schemas/space.json
@@ -103,6 +103,10 @@
         },
         "domain": {
           "type": "string",
+          "allOf": [
+            { "format": "hostname" },
+            { "format": "lowercase" }
+          ],
           "title": "domain",
           "maxLength": 64
         },
diff --git a/src/utils.ts b/src/utils.ts
index a3115c826..d22352070 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -113,6 +113,10 @@ ajv.addFormat('long', {
   validate: () => true
 });
 
+ajv.addFormat('lowercase', {
+  validate: (value: string) => value === value.toLowerCase()
+});
+
 ajv.addFormat('ethValue', {
   validate: (value: string) => {
     if (!value.match(/^([0-9]|[1-9][0-9]+)(\.[0-9]+)?$/)) return false;