diff --git a/lib/routes/client-api/metrics-schema.js b/lib/routes/client-api/metrics-schema.js
index 37b5811714..c446676841 100644
--- a/lib/routes/client-api/metrics-schema.js
+++ b/lib/routes/client-api/metrics-schema.js
@@ -14,10 +14,7 @@ const countSchema = joi
             .number()
             .min(0)
             .default(0),
-        variants: joi.object({
-            arg: joi.string(),
-            value: joi.number().min(0),
-        }),
+        variants: joi.object().pattern(joi.string(), joi.number().min(0)),
     });
 
 const clientMetricsSchema = joi