diff --git a/changelog/unreleased/allow-configuring-additional-routes.md b/changelog/unreleased/allow-configuring-additional-routes.md
new file mode 100644
index 000000000..449d4fcd1
--- /dev/null
+++ b/changelog/unreleased/allow-configuring-additional-routes.md
@@ -0,0 +1,5 @@
+Enhancement: Allow configuring additional routes
+
+Allows adding custom routes to the ocis proxy. This enables customs ocis extensions
+
+https://github.com/owncloud/ocis/pull/7740
diff --git a/services/proxy/pkg/config/config.go b/services/proxy/pkg/config/config.go
index e937c036e..9ff1928e0 100644
--- a/services/proxy/pkg/config/config.go
+++ b/services/proxy/pkg/config/config.go
@@ -26,6 +26,7 @@ type Config struct {
 
 	RoleQuotas            map[string]uint64  `yaml:"role_quotas"`
 	Policies              []Policy           `yaml:"policies"`
+	AdditionalPolicies    []Policy           `yaml:"additional_policies"`
 	OIDC                  OIDC               `yaml:"oidc"`
 	ServiceAccount        ServiceAccount     `yaml:"service_account"`
 	RoleAssignment        RoleAssignment     `yaml:"role_assignment"`
diff --git a/services/proxy/pkg/config/defaults/defaultconfig.go b/services/proxy/pkg/config/defaults/defaultconfig.go
index 460c0b1b3..f7e048730 100644
--- a/services/proxy/pkg/config/defaults/defaultconfig.go
+++ b/services/proxy/pkg/config/defaults/defaultconfig.go
@@ -292,7 +292,7 @@ func EnsureDefaults(cfg *config.Config) {
 // Sanitize sanitizes the configuration
 func Sanitize(cfg *config.Config) {
 	if cfg.Policies == nil {
-		cfg.Policies = DefaultPolicies()
+		cfg.Policies = mergePolicies(DefaultPolicies(), cfg.AdditionalPolicies)
 	}
 
 	if cfg.PolicySelector == nil {
@@ -307,3 +307,21 @@ func Sanitize(cfg *config.Config) {
 		cfg.HTTP.Root = strings.TrimSuffix(cfg.HTTP.Root, "/")
 	}
 }
+
+func mergePolicies(policies []config.Policy, additionalPolicies []config.Policy) []config.Policy {
+	for _, p := range additionalPolicies {
+		found := false
+		for i, po := range policies {
+			if po.Name == p.Name {
+				po.Routes = append(po.Routes, p.Routes...)
+				policies[i] = po
+				found = true
+				break
+			}
+		}
+		if !found {
+			policies = append(policies, p)
+		}
+	}
+	return policies
+}