diff --git a/src/index.ts b/src/index.ts
index e051b72..0db26e9 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,6 +1,4 @@
-import type { BunyanLikeLogger } from './decorator';
-import { Bunyamin } from './decorator';
-import { noopLogger } from './noopLogger';
+import realm from './realm';
 
 export * from './noopLogger';
 export * from './traceEventStream';
@@ -8,12 +6,7 @@ export * from './uniteTraceEvents';
 export * from './wrapLogger';
 export * from './is-debug';
 
-const threadGroups: any[] = [];
-export const bunyamin = new Bunyamin<BunyanLikeLogger>({ logger: noopLogger(), threadGroups });
-export const nobunyamin = new Bunyamin<BunyanLikeLogger>({
-  logger: noopLogger(),
-  threadGroups,
-  immutable: true,
-});
+export const bunyamin = realm.bunyamin;
+export const nobunyamin = realm.nobunyamin;
 
 export default bunyamin;
diff --git a/src/realm.ts b/src/realm.ts
new file mode 100644
index 0000000..c38d2cb
--- /dev/null
+++ b/src/realm.ts
@@ -0,0 +1,31 @@
+import type { BunyanLikeLogger } from './decorator';
+import { Bunyamin } from './decorator';
+import { noopLogger } from './noopLogger';
+
+type Realm = {
+  bunyamin: Bunyamin<BunyanLikeLogger>;
+  nobunyamin: Bunyamin<BunyanLikeLogger>;
+};
+
+function create() {
+  const threadGroups: any[] = [];
+  const bunyamin = new Bunyamin<BunyanLikeLogger>({ logger: noopLogger(), threadGroups });
+  const nobunyamin = new Bunyamin<BunyanLikeLogger>({
+    logger: noopLogger(),
+    threadGroups,
+    immutable: true,
+  });
+
+  return { bunyamin, nobunyamin };
+}
+
+function getCached(): Realm | undefined {
+  return (globalThis as any).__BUNYAMIN__;
+}
+
+function setCached(realm: Realm) {
+  (globalThis as any).__BUNYAMIN__ = realm;
+  return realm;
+}
+
+export default setCached(getCached() ?? create());