diff --git a/src/esbuild/index.ts b/src/esbuild/index.ts
index 448da15c..b9f52236 100644
--- a/src/esbuild/index.ts
+++ b/src/esbuild/index.ts
@@ -131,7 +131,11 @@ export async function runEsbuild(
       globalName: options.globalName,
       jsxFactory: options.jsxFactory,
       jsxFragment: options.jsxFragment,
-      sourcemap: options.sourcemap ? 'external' : false,
+      sourcemap: options.sourcemap
+        ? options.sourcemap === 'inline'
+          ? options.sourcemap
+          : 'external'
+        : false,
       target: options.target,
       footer: options.footer,
       banner: options.banner,
diff --git a/src/options.ts b/src/options.ts
index 5be70077..df37a3d8 100644
--- a/src/options.ts
+++ b/src/options.ts
@@ -58,7 +58,7 @@ export type Options = {
     [k: string]: string
   }
   dts?: boolean | string | DtsConfig
-  sourcemap?: boolean
+  sourcemap?: boolean | 'inline'
   /** Always bundle modules matching given patterns */
   noExternal?: (string | RegExp)[]
   /** Don't bundle these modules */
diff --git a/test/index.test.ts b/test/index.test.ts
index c2fc109c..12550114 100644
--- a/test/index.test.ts
+++ b/test/index.test.ts
@@ -185,7 +185,7 @@ test('bundle graphql-tools with --sourcemap inline flag', async (t) => {
     }
   )
 
-  t.assert(output.includes('//# sourceMappingURL='))
+  t.assert(output.includes('//# sourceMappingURL=data:'))
 })
 
 test('multiple formats', async (t) => {