diff --git a/langfuse-core/src/globalThis.d.ts b/langfuse-core/src/globalThis.d.ts
deleted file mode 100644
index 17d0033e..00000000
--- a/langfuse-core/src/globalThis.d.ts
+++ /dev/null
@@ -1,16 +0,0 @@
-export {};
-
-declare interface DeferLangFuseTrace {
-  id: string;
-  name: string;
-  url: string;
-}
-
-declare global {
-  namespace globalThis {
-    // eslint-disable-next-line no-var
-    var __deferRuntime: {
-      langfuseTraces: (traces: DeferLangFuseTrace[]) => void;
-    };
-  }
-}
diff --git a/langfuse-core/src/index.ts b/langfuse-core/src/index.ts
index 3d61732e..2a17f697 100644
--- a/langfuse-core/src/index.ts
+++ b/langfuse-core/src/index.ts
@@ -23,8 +23,17 @@ import {
   type CreateLangfuseDatasetItemResponse,
   type GetLangfuseDatasetRunResponse,
   type GetLangfuseDatasetRunParams,
+  type DeferRuntime,
 } from "./types";
-import { assert, generateUUID, removeTrailingSlash, retriable, type RetriableOptions, safeSetTimeout } from "./utils";
+import {
+  assert,
+  generateUUID,
+  removeTrailingSlash,
+  retriable,
+  type RetriableOptions,
+  safeSetTimeout,
+  getEnv,
+} from "./utils";
 export * as utils from "./utils";
 import { SimpleEventEmitter } from "./eventemitter";
 import { getCommonReleaseEnvs } from "./release-env";
@@ -85,7 +94,7 @@ abstract class LangfuseCoreStateless {
     this.baseUrl = removeTrailingSlash(options?.baseUrl || "https://cloud.langfuse.com");
     this.flushAt = options?.flushAt ? Math.max(options?.flushAt, 1) : 1;
     this.flushInterval = options?.flushInterval ?? 10000;
-    this.release = options?.release ?? process.env.LANGFUSE_RELEASE ?? getCommonReleaseEnvs() ?? undefined;
+    this.release = options?.release ?? getEnv("LANGFUSE_RELEASE") ?? getCommonReleaseEnvs() ?? undefined;
 
     this._retryOptions = {
       retryCount: options?.fetchRetryCount ?? 3,
@@ -453,10 +462,11 @@ export abstract class LangfuseCore extends LangfuseCoreStateless {
   trace(body?: CreateLangfuseTraceBody): LangfuseTraceClient {
     const id = this.traceStateless(body ?? {});
     const t = new LangfuseTraceClient(this, id);
-    if (process.env.DEFER && body) {
+    if (getEnv("DEFER") && body) {
       try {
-        if (globalThis.__deferRuntime) {
-          __deferRuntime.langfuseTraces([
+        const deferRuntime = getEnv<DeferRuntime>("__deferRuntime");
+        if (deferRuntime) {
+          deferRuntime.langfuseTraces([
             {
               id: id,
               name: body.name || "",
diff --git a/langfuse-core/src/types.ts b/langfuse-core/src/types.ts
index 9149891d..a6958e3c 100644
--- a/langfuse-core/src/types.ts
+++ b/langfuse-core/src/types.ts
@@ -141,3 +141,13 @@ type FixTypes<T> = Omit<
   },
   "externalId" | "traceIdType"
 >;
+
+export type DeferRuntime = {
+  langfuseTraces: (
+    traces: {
+      id: string;
+      name: string;
+      url: string;
+    }[]
+  ) => void;
+};
diff --git a/langfuse-core/src/utils.ts b/langfuse-core/src/utils.ts
index 13389fdc..a3a15594 100644
--- a/langfuse-core/src/utils.ts
+++ b/langfuse-core/src/utils.ts
@@ -81,3 +81,13 @@ export function safeSetTimeout(fn: () => void, timeout: number): any {
   t?.unref && t?.unref();
   return t;
 }
+
+export function getEnv<T = string>(key: string): T | undefined {
+  if (typeof process !== "undefined") {
+    return process.env[key] as T;
+  }
+  if (typeof globalThis !== "undefined") {
+    return (globalThis as any)[key];
+  }
+  return;
+}