diff --git a/openapi.go b/openapi.go
index e769e1c..3278b82 100644
--- a/openapi.go
+++ b/openapi.go
@@ -36,6 +36,7 @@ type SpecBuilder struct {
 	Servers                 []string
 	LicenseName             string
 	LicenseURL              string
+	SecuritySchemes         map[string]any
 	ExternalDocsDescription string
 	ExternalDocsURL         string
 	PprofEnabled            bool
@@ -179,14 +180,8 @@ func (sb *SpecBuilder) Build(groups []RouteGroup) ([]byte, error) {
 				},
 			},
 		},
-		"securitySchemes": map[string]any{
-			"bearerAuth": map[string]any{
-				"type":         "http",
-				"scheme":       "bearer",
-				"bearerFormat": "JWT",
-			},
-		},
-		"headers": deprecationHeaderComponents(),
+		"securitySchemes": securitySchemeComponents(sb.SecuritySchemes),
+		"headers":         deprecationHeaderComponents(),
 	}
 
 	return json.MarshalIndent(spec, "", "  ")
@@ -636,6 +631,29 @@ func deprecationHeaderComponents() map[string]any {
 	}
 }
 
+// securitySchemeComponents builds the OpenAPI security scheme registry.
+// bearerAuth stays available by default, while callers can add or override
+// additional scheme definitions for custom security requirements.
+func securitySchemeComponents(overrides map[string]any) map[string]any {
+	schemes := map[string]any{
+		"bearerAuth": map[string]any{
+			"type":         "http",
+			"scheme":       "bearer",
+			"bearerFormat": "JWT",
+		},
+	}
+
+	for name, scheme := range overrides {
+		name = strings.TrimSpace(name)
+		if name == "" || scheme == nil {
+			continue
+		}
+		schemes[name] = scheme
+	}
+
+	return schemes
+}
+
 // buildTags generates the tags array from all RouteGroups.
 func (sb *SpecBuilder) buildTags(groups []preparedRouteGroup) []map[string]any {
 	tags := []map[string]any{
diff --git a/openapi_test.go b/openapi_test.go
index 14620fb..f726ca0 100644
--- a/openapi_test.go
+++ b/openapi_test.go
@@ -208,6 +208,55 @@ func TestSpecBuilder_Good_EmptyGroups(t *testing.T) {
 	}
 }
 
+func TestSpecBuilder_Good_CustomSecuritySchemesAreMerged(t *testing.T) {
+	sb := &api.SpecBuilder{
+		Title:   "Test",
+		Version: "1.0.0",
+		SecuritySchemes: map[string]any{
+			"apiKeyAuth": map[string]any{
+				"type": "apiKey",
+				"in":   "header",
+				"name": "X-API-Key",
+			},
+		},
+	}
+
+	data, err := sb.Build(nil)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	var spec map[string]any
+	if err := json.Unmarshal(data, &spec); err != nil {
+		t.Fatalf("invalid JSON: %v", err)
+	}
+
+	components := spec["components"].(map[string]any)
+	schemes := components["securitySchemes"].(map[string]any)
+
+	bearerAuth, ok := schemes["bearerAuth"].(map[string]any)
+	if !ok {
+		t.Fatal("expected default bearerAuth security scheme to remain present")
+	}
+	if bearerAuth["scheme"] != "bearer" {
+		t.Fatalf("expected bearerAuth scheme to stay bearer, got %v", bearerAuth["scheme"])
+	}
+
+	apiKeyAuth, ok := schemes["apiKeyAuth"].(map[string]any)
+	if !ok {
+		t.Fatal("expected custom apiKeyAuth security scheme to be merged")
+	}
+	if apiKeyAuth["type"] != "apiKey" {
+		t.Fatalf("expected apiKeyAuth.type=apiKey, got %v", apiKeyAuth["type"])
+	}
+	if apiKeyAuth["in"] != "header" {
+		t.Fatalf("expected apiKeyAuth.in=header, got %v", apiKeyAuth["in"])
+	}
+	if apiKeyAuth["name"] != "X-API-Key" {
+		t.Fatalf("expected apiKeyAuth.name=X-API-Key, got %v", apiKeyAuth["name"])
+	}
+}
+
 func TestSpecBuilder_Good_SwaggerUIPathExtension(t *testing.T) {
 	sb := &api.SpecBuilder{
 		Title:       "Test",