diff --git a/config.yaml b/config.yaml
index 46919209..2b237d7b 100644
--- a/config.yaml
+++ b/config.yaml
@@ -177,7 +177,7 @@ client:
     ## Validation Regex on the request SDK Key
     ## By default Agent assumes only alphanumeric characters as part of the SDK Key string.
     ## https://github.com/google/re2/wiki/Syntax
-    SdkKeyRegex: "^[a-zA-Z0-9=-]+(:[a-zA-Z0-9=-]+)?$"
+    sdkKeyRegex: "^[\\w=]+(:[\\w=]+)?$"
     ## configure optional User profile service
     userProfileService:
       default: ""
diff --git a/config/config.go b/config/config.go
index 8b739220..9e0eb059 100644
--- a/config/config.go
+++ b/config/config.go
@@ -82,7 +82,7 @@ func NewDefaultConfig() *AgentConfig {
 			DatafileURLTemplate: "https://cdn.optimizely.com/datafiles/%s.json",
 			EventURL:            "https://logx.optimizely.com/v1/events",
 			// https://github.com/google/re2/wiki/Syntax
-			SdkKeyRegex: "^[a-zA-Z0-9=-]+(:[a-zA-Z0-9=-]+)?$",
+			SdkKeyRegex: "^[\\w=]+(:[\\w=]+)?$",
 			UserProfileService: UserProfileServiceConfigs{
 				"default":  "",
 				"services": map[string]interface{}{},