diff --git a/app/common/gristUrls.ts b/app/common/gristUrls.ts
index 8779d23a..048e3504 100644
--- a/app/common/gristUrls.ts
+++ b/app/common/gristUrls.ts
@@ -185,12 +185,20 @@ export interface OrgUrlInfo {
   orgInPath?: string;     // If /o/{orgInPath} should be used to access the requested org.
 }
 
-function isDocInternalUrl(host: string) {
-  if (!process.env.APP_DOC_INTERNAL_URL) { return false; }
-  const internalUrl = new URL('/', process.env.APP_DOC_INTERNAL_URL);
+function isInternalUrl(host: string, envValue?: string) {
+  if (!envValue) { return false; }
+  const internalUrl = new URL('/', envValue);
   return internalUrl.host === host;
 }
 
+function isDocInternalUrl(host: string) {
+  return isInternalUrl(host, process.env.APP_DOC_INTERNAL_URL);
+}
+
+function isHomeInternalUrl(host: string) {
+  return isInternalUrl(host, process.env.APP_HOME_INTERNAL_URL);
+}
+
 /**
  * Given host (optionally with port), baseDomain, and pluginUrl, determine whether to interpret host
  * as a custom domain, a native domain, or a plugin domain.
@@ -208,7 +216,12 @@ export function getHostType(host: string, options: {
 
   const hostname = host.split(":")[0];
   if (!options.baseDomain) { return 'native'; }
-  if (hostname === 'localhost' || isDocInternalUrl(host) || hostname.endsWith(options.baseDomain)) {
+  if (
+    hostname === 'localhost' ||
+    isDocInternalUrl(host) ||
+    hostname.endsWith(options.baseDomain) ||
+    isHomeInternalUrl(host)
+  ) {
     return 'native';
   }
   return 'custom';
diff --git a/app/server/lib/BootProbes.ts b/app/server/lib/BootProbes.ts
index 7cddb99f..e0ed47fe 100644
--- a/app/server/lib/BootProbes.ts
+++ b/app/server/lib/BootProbes.ts
@@ -77,7 +77,7 @@ const _homeUrlReachableProbe: Probe = {
   id: 'reachable',
   name: 'Grist is reachable',
   apply: async (server, req) => {
-    const url = server.getHomeUrl(req);
+    const url = server.getHomeInternalUrl(req);
     try {
       const resp = await fetch(url);
       if (resp.status !== 200) {
@@ -102,7 +102,7 @@ const _statusCheckProbe: Probe = {
   id: 'health-check',
   name: 'Built-in Health check',
   apply: async (server, req) => {
-    const baseUrl = server.getHomeUrl(req);
+    const baseUrl = server.getHomeInternalUrl(req);
     const url = new URL(baseUrl);
     url.pathname = removeTrailingSlash(url.pathname) + '/status';
     try {
diff --git a/app/server/lib/DocApi.ts b/app/server/lib/DocApi.ts
index 95d54540..5eb391f2 100644
--- a/app/server/lib/DocApi.ts
+++ b/app/server/lib/DocApi.ts
@@ -1098,7 +1098,8 @@ export class DocWorkerApi {
       if (req.body.sourceDocId) {
         options.sourceDocId = await this._confirmDocIdForRead(req, String(req.body.sourceDocId));
         // Make sure that if we wanted to download the full source, we would be allowed.
-        const result = await fetch(this._grist.getHomeUrl(req, `/api/docs/${options.sourceDocId}/download?dryrun=1`), {
+        const homeUrl = this._grist.getHomeInternalUrl(req, `/api/docs/${options.sourceDocId}/download?dryrun=1`);
+        const result = await fetch(homeUrl, {
           method: 'GET',
           headers: {
             ...getTransitiveHeaders(req),
@@ -1111,7 +1112,7 @@ export class DocWorkerApi {
         }
         // We should make sure the source document has flushed recently.
         // It may not be served by the same worker, so work through the api.
-        await fetch(this._grist.getHomeUrl(req, `/api/docs/${options.sourceDocId}/flush`), {
+        await fetch(this._grist.getHomeInternalUrl(req, `/api/docs/${options.sourceDocId}/flush`), {
           method: 'POST',
           headers: {
             ...getTransitiveHeaders(req),
@@ -1170,7 +1171,7 @@ export class DocWorkerApi {
       const showDetails = isAffirmative(req.query.detail);
       const docSession = docSessionFromRequest(req);
       const {states} = await this._getStates(docSession, activeDoc);
-      const ref = await fetch(this._grist.getHomeUrl(req, `/api/docs/${req.params.docId2}/states`), {
+      const ref = await fetch(this._grist.getHomeInternalUrl(req, `/api/docs/${req.params.docId2}/states`), {
         headers: {
           ...getTransitiveHeaders(req),
           'Content-Type': 'application/json',
@@ -1199,7 +1200,7 @@ export class DocWorkerApi {
 
         // Calculate changes from the (common) parent to the current version of the other document.
         const url = `/api/docs/${req.params.docId2}/compare?left=${parent.h}`;
-        const rightChangesReq = await fetch(this._grist.getHomeUrl(req, url), {
+        const rightChangesReq = await fetch(this._grist.getHomeInternalUrl(req, url), {
           headers: {
             ...getTransitiveHeaders(req),
             'Content-Type': 'application/json',
diff --git a/app/server/lib/FlexServer.ts b/app/server/lib/FlexServer.ts
index ec623e1b..2896eb47 100644
--- a/app/server/lib/FlexServer.ts
+++ b/app/server/lib/FlexServer.ts
@@ -330,7 +330,7 @@ export class FlexServer implements GristServer {
    * based on domain).
    */
   public async getHomeUrlByDocId(docId: string, relPath: string = ''): Promise<string> {
-    return new URL(relPath, this.getDefaultHomeUrl()).href;
+    return new URL(relPath, this.getDefaultHomeInternalUrl()).href;
   }
 
   // Get the port number the server listens on.  This may be different from the port
@@ -1448,7 +1448,7 @@ export class FlexServer implements GristServer {
       const permitStore = this.getPermitStore();
       const notifier = this.getNotifier();
       const loginSystem = await this.resolveLoginSystem();
-      const homeUrl = this.getHomeUrl(req).replace(/\/$/, '');
+      const homeUrl = this.getHomeInternalUrl(req).replace(/\/$/, '');
       return new Doom(dbManager, permitStore, notifier, loginSystem, homeUrl);
     };
 
@@ -2432,7 +2432,7 @@ export class FlexServer implements GristServer {
     const workspace = workspaces.find(w => w.name === 'Home');
     if (!workspace) { throw new Error('Home workspace not found'); }
 
-    const copyDocUrl = this.getHomeUrl(req, '/api/docs');
+    const copyDocUrl = this.getHomeInternalUrl(req, '/api/docs');
     const response = await fetch(copyDocUrl, {
       headers: {
         ...getTransitiveHeaders(req),
diff --git a/app/server/lib/uploads.ts b/app/server/lib/uploads.ts
index f4170da2..ce89238a 100644
--- a/app/server/lib/uploads.ts
+++ b/app/server/lib/uploads.ts
@@ -417,7 +417,7 @@ export async function fetchDoc(server: GristServer, docId: string, req: Request,
 
   // Find the doc worker responsible for the document we wish to copy.
   // The backend needs to be well configured for this to work.
-  const homeUrl = server.getHomeUrl(req);
+  const homeUrl = server.getHomeInternalUrl(req);
   const fetchUrl = new URL(`/api/worker/${docId}`, homeUrl);
   const response: FetchResponse = await Deps.fetch(fetchUrl.href, {headers});
   await _checkForError(response);