diff --git a/packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap b/packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap
index be90805d18..9f21ebc79e 100644
--- a/packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap
+++ b/packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap
@@ -64,6 +64,7 @@ Object {
   },
   "serializer": Object {
     "createModuleIdFactory": [Function],
+    "customSerializer": null,
     "experimentalSerializerHook": [Function],
     "getModulesRunBeforeMainModule": [Function],
     "getPolyfills": [Function],
@@ -184,6 +185,7 @@ Object {
   },
   "serializer": Object {
     "createModuleIdFactory": [Function],
+    "customSerializer": null,
     "experimentalSerializerHook": [Function],
     "getModulesRunBeforeMainModule": [Function],
     "getPolyfills": [Function],
diff --git a/packages/metro-config/src/configTypes.flow.js b/packages/metro-config/src/configTypes.flow.js
index eca73d99ce..08d0ba7b08 100644
--- a/packages/metro-config/src/configTypes.flow.js
+++ b/packages/metro-config/src/configTypes.flow.js
@@ -26,6 +26,7 @@ import type {TransformVariants} from 'metro/src/ModuleGraph/types.flow.js';
 import type {DynamicRequiresBehavior} from 'metro/src/ModuleGraph/worker/collectDependencies';
 import type Server from 'metro/src/Server';
 import type {Reporter} from 'metro/src/lib/reporting';
+import type {Options} from 'metro/src/DeltaBundler/Serializers/plainJSBundle';
 
 export type PostMinifyProcess = ({
   code: string,
@@ -115,6 +116,12 @@ type ResolverConfigT = {|
 
 type SerializerConfigT = {|
   createModuleIdFactory: () => (path: string) => number,
+  customSerializer: ?(
+    entryPoint: string,
+    preModules: $ReadOnlyArray<Module<>>,
+    graph: Graph<>,
+    options: Options,
+  ) => string,
   experimentalSerializerHook: (graph: Graph<>, delta: DeltaResult<>) => mixed,
   getModulesRunBeforeMainModule: (entryFilePath: string) => Array<string>,
   getPolyfills: ({platform: ?string}) => $ReadOnlyArray<string>,
diff --git a/packages/metro-config/src/convertConfig.js b/packages/metro-config/src/convertConfig.js
index d854e15951..ea8c5134f6 100644
--- a/packages/metro-config/src/convertConfig.js
+++ b/packages/metro-config/src/convertConfig.js
@@ -111,6 +111,7 @@ async function convertOldToNew({
       useWatchman: true,
     },
     serializer: {
+      customSerializer: defaultConfig.serializer.customSerializer,
       createModuleIdFactory:
         createModuleIdFactory || defaultConfig.serializer.createModuleIdFactory,
       polyfillModuleNames: getPolyfillModuleNames(),
diff --git a/packages/metro-config/src/defaults/index.js b/packages/metro-config/src/defaults/index.js
index d820fc8fa9..816af7d25a 100644
--- a/packages/metro-config/src/defaults/index.js
+++ b/packages/metro-config/src/defaults/index.js
@@ -54,6 +54,7 @@ const getDefaultValues = (projectRoot: ?string): ConfigT => ({
     processModuleFilter: module => true,
     createModuleIdFactory: defaultCreateModuleIdFactory,
     experimentalSerializerHook: () => {},
+    customSerializer: null,
   },
 
   server: {
diff --git a/packages/metro/src/DeltaBundler/Serializers/plainJSBundle.js b/packages/metro/src/DeltaBundler/Serializers/plainJSBundle.js
index 461381a7c1..9c7d76f150 100644
--- a/packages/metro/src/DeltaBundler/Serializers/plainJSBundle.js
+++ b/packages/metro/src/DeltaBundler/Serializers/plainJSBundle.js
@@ -17,7 +17,7 @@ const {isJsModule, wrapModule} = require('./helpers/js');
 import type {ModuleMap} from '../../lib/bundle-modules/types.flow';
 import type {Graph, Module, SerializerOptions} from '../types.flow';
 
-type Options =
+export type Options =
   | {|
       ...SerializerOptions,
       embedDelta: false,
diff --git a/packages/metro/src/Server.js b/packages/metro/src/Server.js
index 750b080259..a409e59713 100644
--- a/packages/metro/src/Server.js
+++ b/packages/metro/src/Server.js
@@ -677,7 +677,7 @@ class Server {
         inlineSourceMap: serializerOptions.inlineSourceMap,
       };
 
-      const bundle = plainJSBundle(
+      const serializerArguments = [
         entryFile,
         revision.prepend,
         revision.graph,
@@ -689,7 +689,11 @@ class Server {
               revisionId: revision.id,
             })
           : Object.assign({}, options, {embedDelta: false}),
-      );
+      ];
+      const possibleCustomSerializer = this._config.serializer.customSerializer;
+      const bundle = possibleCustomSerializer
+        ? possibleCustomSerializer(...serializerArguments)
+        : plainJSBundle(...serializerArguments);
 
       return {
         numModifiedFiles: delta.reset