diff --git a/README.md b/README.md
index 29008223..a49e0b30 100644
--- a/README.md
+++ b/README.md
@@ -256,7 +256,6 @@ APP_STATIC_URL | url prefix for static resources
 APP_STATIC_INCLUDE_CUSTOM_CSS | set to "true" to include custom.css (from APP_STATIC_URL) in static pages
 APP_UNTRUSTED_URL   | URL at which to serve/expect plugin content.
 GRIST_ADAPT_DOMAIN  | set to "true" to support multiple base domains (careful, host header should be trustworthy)
-GRIST_ALLOWED_HOSTS | comma-separated list of permitted domains origin for requests (e.g. my.site,another.com)
 GRIST_APP_ROOT      | directory containing Grist sandbox and assets (specifically the sandbox and static subdirectories).
 GRIST_BACKUP_DELAY_SECS | wait this long after a doc change before making a backup
 GRIST_BOOT_KEY | if set, offer diagnostics at /boot/GRIST_BOOT_KEY
diff --git a/app/server/lib/Authorizer.ts b/app/server/lib/Authorizer.ts
index c1d53361..761e76f2 100644
--- a/app/server/lib/Authorizer.ts
+++ b/app/server/lib/Authorizer.ts
@@ -18,7 +18,7 @@ import {makeId} from 'app/server/lib/idUtils';
 import log from 'app/server/lib/log';
 import {IPermitStore, Permit} from 'app/server/lib/Permit';
 import {AccessTokenInfo} from 'app/server/lib/AccessTokens';
-import {allowHost, getOriginUrl, isEnvironmentAllowedHost, optStringParam} from 'app/server/lib/requestUtils';
+import {allowHost, getOriginUrl, optStringParam} from 'app/server/lib/requestUtils';
 import * as cookie from 'cookie';
 import {NextFunction, Request, RequestHandler, Response} from 'express';
 import {IncomingMessage} from 'http';
@@ -271,7 +271,7 @@ export async function addRequestUser(
       // custom-domain owner could hijack such sessions.
       const allowedOrg = getAllowedOrgForSessionID(mreq.sessionID);
       if (allowedOrg) {
-        if (allowHost(req, allowedOrg.host) || isEnvironmentAllowedHost(allowedOrg.host)) {
+        if (allowHost(req, allowedOrg.host)) {
           customHostSession = ` custom-host-match ${allowedOrg.host}`;
         } else {
           // We need an exception for internal forwarding from home server to doc-workers. These use
diff --git a/app/server/lib/requestUtils.ts b/app/server/lib/requestUtils.ts
index 890b9702..e25cef58 100644
--- a/app/server/lib/requestUtils.ts
+++ b/app/server/lib/requestUtils.ts
@@ -8,7 +8,6 @@ import {RequestWithGrist} from 'app/server/lib/GristServer';
 import log from 'app/server/lib/log';
 import {Permit} from 'app/server/lib/Permit';
 import {Request, Response} from 'express';
-import _ from 'lodash';
 import {Writable} from 'stream';
 
 // log api details outside of dev environment (when GRIST_HOSTED_VERSION is set)
@@ -87,7 +86,7 @@ export function trustOrigin(req: Request, resp: Response): boolean {
   const origin = req.get('origin');
   if (!origin) { return true; } // Not a CORS request.
   if (process.env.GRIST_HOST && req.hostname === process.env.GRIST_HOST) { return true; }
-  if (!allowHost(req, new URL(origin)) && !isEnvironmentAllowedHost(new URL(origin))) { return false; }
+  if (!allowHost(req, new URL(origin))) { return false; }
 
   // For a request to a custom domain, the full hostname must match.
   resp.header("Access-Control-Allow-Origin", origin);
@@ -104,14 +103,14 @@ export function allowHost(req: Request, allowedHost: string|URL) {
   const allowedUrl = (typeof allowedHost === 'string') ? new URL(`${proto}://${allowedHost}`) : allowedHost;
   if (mreq.isCustomHost) {
     // For a request to a custom domain, the full hostname must match.
-  return actualUrl.hostname === allowedUrl.hostname;
+    return actualUrl.hostname === allowedUrl.hostname;
   } else {
     // For requests to a native subdomains, only the base domain needs to match.
     const allowedDomain = parseSubdomain(allowedUrl.hostname);
     const actualDomain = parseSubdomain(actualUrl.hostname);
-    return (!_.isEmpty(actualDomain) ?
+    return actualDomain.base ?
       actualDomain.base === allowedDomain.base :
-      allowedUrl.hostname === actualUrl.hostname);
+      actualUrl.hostname === allowedUrl.hostname;
   }
 }
 
@@ -119,13 +118,6 @@ export function matchesBaseDomain(domain: string, baseDomain: string) {
   return domain === baseDomain || domain.endsWith("." + baseDomain);
 }
 
-export function isEnvironmentAllowedHost(url: string|URL) {
-  const urlHost = (typeof url === 'string') ? url : url.hostname;
-  return (process.env.GRIST_ALLOWED_HOSTS || "").split(",").some(domain =>
-    domain && matchesBaseDomain(urlHost, domain)
-  );
-}
-
 export function isParameterOn(parameter: any): boolean {
   return gutil.isAffirmative(parameter);
 }
diff --git a/test/server/lib/DocApi.ts b/test/server/lib/DocApi.ts
index 22401c6f..2754fd6e 100644
--- a/test/server/lib/DocApi.ts
+++ b/test/server/lib/DocApi.ts
@@ -4865,23 +4865,6 @@ function testDocApi() {
   });
 
   describe("Allowed Origin", () => {
-    it('should allow only example.com', async () => {
-      async function checkOrigin(origin: string, allowed: boolean) {
-        const resp = await axios.get(`${serverUrl}/api/docs/${docIds.Timesheets}/tables/Table1/data`,
-          {...chimpy, headers: {...chimpy.headers, "Origin": origin}}
-        );
-        assert.equal(resp.headers['access-control-allow-credentials'], allowed ? 'true' : undefined);
-        assert.equal(resp.status, allowed ? 200 : 403);
-      }
-
-      await checkOrigin("https://www.toto.com", false);
-      await checkOrigin("https://badexample.com", false);
-      await checkOrigin("https://bad.com/example.com/toto", false);
-      await checkOrigin("https://example.com/path", true);
-      await checkOrigin("https://example.com:3000/path", true);
-      await checkOrigin("https://good.example.com/toto", true);
-    });
-
     it("should respond with correct CORS headers", async function () {
       const wid = await getWorkspaceId(userApi, 'Private');
       const docId = await userApi.newDoc({name: 'CorsTestDoc'}, wid);
diff --git a/test/server/lib/helpers/TestServer.ts b/test/server/lib/helpers/TestServer.ts
index 0f8efb65..51a5d39f 100644
--- a/test/server/lib/helpers/TestServer.ts
+++ b/test/server/lib/helpers/TestServer.ts
@@ -49,7 +49,6 @@ export class TestServer {
       GRIST_PORT: '0',
       GRIST_DISABLE_S3: 'true',
       REDIS_URL: process.env.TEST_REDIS_URL,
-      GRIST_ALLOWED_HOSTS: `example.com,localhost`,
       GRIST_TRIGGER_WAIT_DELAY: '100',
       // this is calculated value, some tests expect 4 attempts and some will try 3 times
       GRIST_TRIGGER_MAX_ATTEMPTS: '4',