diff --git a/generator/typescript/index.d.tstemplate b/generator/typescript/index.d.tstemplate
index f3517f9b..9e449484 100644
--- a/generator/typescript/index.d.tstemplate
+++ b/generator/typescript/index.d.tstemplate
@@ -19,6 +19,8 @@ export interface DropboxAuthOptions {
   fetch?: Function;
   // A custom domain to use when making api requests. This should only be used for testing as scaffolding to avoid making network requests.
   domain?: string;
+  // A custom delimiter to use when separating domain from subdomain. This should only be used for testing as scaffolding.
+  domainDelimiter?: string;
 }
 
 export class DropboxAuth {
@@ -173,6 +175,8 @@ export interface DropboxOptions {
   fetch?: Function;
   // A custom domain to use when making api requests. This should only be used for testing as scaffolding to avoid making network requests.
   domain?: string;
+  // A custom delimiter to use when separating domain subdomain. This should only be used for testing as scaffolding.
+  domainDelimiter?: string;
 }
 
 export class DropboxResponseError<T> {
diff --git a/package-lock.json b/package-lock.json
index 81fccb02..ee1635e1 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "dropbox",
-  "version": "9.8.0",
+  "version": "9.8.5",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index bc2d4efb..63995074 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "dropbox",
-    "version": "9.8.4",
+    "version": "9.8.5",
     "registry": "npm",
     "description": "The Dropbox JavaScript SDK is a lightweight, promise based interface to the Dropbox v2 API that works in both nodejs and browser environments.",
     "main": "cjs/index.js",
diff --git a/src/auth.js b/src/auth.js
index 3de1925e..6ea9b414 100644
--- a/src/auth.js
+++ b/src/auth.js
@@ -51,6 +51,8 @@ const IncludeGrantedScopes = ['none', 'user', 'team'];
  * authentication URL and refresh access tokens.
  * @arg {String} [options.domain] - A custom domain to use when making api requests. This
  * should only be used for testing as scaffolding to avoid making network requests.
+ * @arg {String} [options.domainDelimiter] - A custom delimiter to use when separating domain from
+ * subdomain. This should only be used for testing as scaffolding.
  */
 export default class DropboxAuth {
   constructor(options) {
@@ -64,6 +66,7 @@ export default class DropboxAuth {
     this.clientSecret = options.clientSecret;
 
     this.domain = options.domain;
+    this.domainDelimiter = options.domainDelimiter;
   }
 
   /**
@@ -293,7 +296,7 @@ export default class DropboxAuth {
     if (!clientId) {
       throw new Error('A client id is required. You can set the client id using .setClientId().');
     }
-    let path = OAuth2TokenUrl(this.domain);
+    let path = OAuth2TokenUrl(this.domain, this.domainDelimiter);
     path += '?grant_type=authorization_code';
     path += `&code=${code}`;
     path += `&client_id=${clientId}`;
@@ -343,7 +346,7 @@ export default class DropboxAuth {
      * @returns {Promise<*>}
      */
   refreshAccessToken(scope = null) {
-    let refreshUrl = OAuth2TokenUrl(this.domain);
+    let refreshUrl = OAuth2TokenUrl(this.domain, this.domainDelimiter);
     const clientId = this.getClientId();
     const clientSecret = this.getClientSecret();
 
diff --git a/src/dropbox.js b/src/dropbox.js
index a18d65d9..57972e7f 100644
--- a/src/dropbox.js
+++ b/src/dropbox.js
@@ -48,6 +48,8 @@ const b64 = typeof btoa === 'undefined'
  * authentication URL and refresh access tokens.
  * @arg {String} [options.domain] - A custom domain to use when making api requests. This
  * should only be used for testing as scaffolding to avoid making network requests.
+ * @arg {String} [options.domainDelimiter] - A custom delimiter to use when separating domain from
+ * subdomain. This should only be used for testing as scaffolding.
  */
 export default class Dropbox {
   constructor(options) {
@@ -65,6 +67,7 @@ export default class Dropbox {
     this.pathRoot = options.pathRoot;
 
     this.domain = options.domain;
+    this.domainDelimiter = options.domainDelimiter;
 
     Object.assign(this, routes);
   }
@@ -129,7 +132,10 @@ export default class Dropbox {
         this.setCommonHeaders(fetchOptions);
         return fetchOptions;
       })
-      .then((fetchOptions) => this.fetch(baseApiUrl(host, this.domain) + path, fetchOptions))
+      .then((fetchOptions) => this.fetch(
+        baseApiUrl(host, this.domain, this.domainDelimiter) + path,
+        fetchOptions,
+      ))
       .then((res) => parseResponse(res));
   }
 
@@ -152,7 +158,10 @@ export default class Dropbox {
 
         return fetchOptions;
       })
-      .then((fetchOptions) => this.fetch(baseApiUrl(host, this.domain) + path, fetchOptions))
+      .then((fetchOptions) => this.fetch(
+        baseApiUrl(host, this.domain, this.domainDelimiter) + path,
+        fetchOptions,
+      ))
       .then((res) => parseDownloadResponse(res));
   }
 
@@ -180,7 +189,10 @@ export default class Dropbox {
 
         return fetchOptions;
       })
-      .then((fetchOptions) => this.fetch(baseApiUrl(host, this.domain) + path, fetchOptions))
+      .then((fetchOptions) => this.fetch(
+        baseApiUrl(host, this.domain, this.domainDelimiter) + path,
+        fetchOptions,
+      ))
       .then((res) => parseResponse(res));
   }
 
diff --git a/types/index.d.ts b/types/index.d.ts
index f7d177df..2a048fdd 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -20,6 +20,8 @@ export interface DropboxAuthOptions {
   fetch?: Function;
   // A custom domain to use when making api requests. This should only be used for testing as scaffolding to avoid making network requests.
   domain?: string;
+  // A custom delimiter to use when separating domain from subdomain. This should only be used for testing as scaffolding.
+  domainDelimiter?: string;
 }
 
 export class DropboxAuth {
@@ -174,6 +176,8 @@ export interface DropboxOptions {
   fetch?: Function;
   // A custom domain to use when making api requests. This should only be used for testing as scaffolding to avoid making network requests.
   domain?: string;
+  // A custom delimiter to use when separating domain subdomain. This should only be used for testing as scaffolding.
+  domainDelimiter?: string;
 }
 
 export class DropboxResponseError<T> {