diff --git a/lib/core/config-defaults.ts b/lib/core/config-defaults.ts
index 15a8934..7ac6624 100644
--- a/lib/core/config-defaults.ts
+++ b/lib/core/config-defaults.ts
@@ -2,7 +2,9 @@ import { parseQuery, stringifyQuery } from '@/core/serializer/query-serializer'
 import { deepClone } from '@/shared/helpers/deep-clone'
 import { parseUrl } from './serializer/url-serializer'
 
-export function normalizeConfig(config?: FluentUrlConfig): FluentUrlConfig {
+export function normalizeConfig(
+  config?: Partial<FluentUrlConfig>,
+): FluentUrlConfig {
   return {
     parseQuery: config?.parseQuery ?? parseQuery,
     stringifyQuery: config?.stringifyQuery ?? stringifyQuery,
@@ -31,3 +33,27 @@ export function normalizeOptions(args: {
     queries: deepClone(urlOrOptions?.queries) ?? Object.create(null),
   }
 }
+
+export function mergeConfig(
+  current: FluentUrlConfig,
+  merge?: Partial<FluentUrlConfig>,
+): FluentUrlConfig {
+  return {
+    parseQuery: merge?.parseQuery ?? current.parseQuery,
+    stringifyQuery: merge?.stringifyQuery ?? current.stringifyQuery,
+  }
+}
+
+export function mergeOptions(
+  current: FLuentUrlPlainObject,
+  merge?: Partial<FLuentUrlPlainObject>,
+): FLuentUrlPlainObject {
+  return {
+    protocol: merge?.protocol ?? current.protocol,
+    hostname: merge?.hostname ?? current.hostname,
+    paths: merge?.paths ?? current.paths,
+    port: merge?.port ?? current.port,
+    fragment: merge?.fragment ?? current.fragment,
+    queries: merge?.queries ?? current.queries,
+  }
+}
diff --git a/lib/core/fluent-url.ts b/lib/core/fluent-url.ts
index 8244500..65b3faa 100644
--- a/lib/core/fluent-url.ts
+++ b/lib/core/fluent-url.ts
@@ -1,4 +1,9 @@
-import { normalizeConfig, normalizeOptions } from '@/core/config-defaults'
+import {
+  mergeConfig,
+  mergeOptions,
+  normalizeConfig,
+  normalizeOptions,
+} from '@/core/config-defaults'
 import { deepClone } from '@/shared/helpers/deep-clone'
 import { stringifyUrl } from './serializer/url-serializer'
 
@@ -13,7 +18,7 @@ export class FluentUrl {
 
   constructor(
     urlOrOptions?: Partial<FLuentUrlPlainObject> | string,
-    config?: FluentUrlConfig,
+    config?: Partial<FluentUrlConfig>,
   ) {
     this.config = normalizeConfig(config)
 
@@ -69,18 +74,18 @@ export class FluentUrl {
     config?: FluentUrlConfig,
   ): FluentUrl {
     return new FluentUrl(
-      {
-        protocol: options?.protocol ?? this.protocol,
-        hostname: options?.hostname ?? this.hostname,
-        paths: options?.paths ?? this.paths,
-        port: options?.port ?? this.port,
-        fragment: options?.fragment ?? this.fragment,
-        queries: options?.queries ?? this.queries,
-      },
-      {
-        parseQuery: config?.parseQuery ?? this.config.parseQuery,
-        stringifyQuery: config?.stringifyQuery ?? this.config.stringifyQuery,
-      },
+      mergeOptions(
+        {
+          protocol: this.protocol,
+          hostname: this.hostname,
+          paths: this.paths,
+          port: this.port,
+          fragment: this.fragment,
+          queries: this.queries,
+        },
+        options,
+      ),
+      mergeConfig(this.config, config),
     )
   }
 }