diff --git a/.env b/.env
deleted file mode 100644
index 7bc3e94..0000000
--- a/.env
+++ /dev/null
@@ -1,5 +0,0 @@
-# This setting allows to fix the homeserver.
-# If you set this setting, the user will not be able to select
-# the server and have to use synapse-admin with this server.
-
-#REACT_APP_SERVER=https://yourmatrixserver.example.com
\ No newline at end of file
diff --git a/Dockerfile b/Dockerfile
index f936a8c..4e76929 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,13 +1,12 @@
 # Builder
 FROM node:lts as builder
 LABEL org.opencontainers.image.url=https://github.com/Awesome-Technologies/synapse-admin org.opencontainers.image.source=https://github.com/Awesome-Technologies/synapse-admin
-ARG REACT_APP_SERVER
 
 WORKDIR /src
 
 COPY . /src
 RUN yarn --network-timeout=300000 install --immutable
-RUN REACT_APP_SERVER=$REACT_APP_SERVER yarn build
+RUN yarn build
 
 
 # App
diff --git a/README.md b/README.md
index 89211de..751f7d0 100644
--- a/README.md
+++ b/README.md
@@ -64,11 +64,6 @@ You have three options:
 - download dependencies: `yarn install`
 - start web server: `yarn start`
 
-You can fix the homeserver, so that the user can no longer define it himself.
-Either you define it at startup (e.g. `REACT_APP_SERVER=https://yourmatrixserver.example.com yarn start`)
-or by editing it in the [.env](.env) file. See also the
-[documentation](https://create-react-app.dev/docs/adding-custom-environment-variables/).
-
 #### Steps for 3)
 
 - run the Docker container from the public docker registry: `docker run -p 8080:80 awesometechnologies/synapse-admin` or use the [docker-compose.yml](docker-compose.yml): `docker-compose up -d`
@@ -76,8 +71,6 @@ or by editing it in the [.env](.env) file. See also the
   > note: if you're building on an architecture other than amd64 (for example a raspberry pi), make sure to define a maximum ram for node. otherwise the build will fail.
 
   ```yml
-  version: "3"
-
   services:
     synapse-admin:
       container_name: synapse-admin
@@ -88,7 +81,6 @@ or by editing it in the [.env](.env) file. See also the
         #   - NODE_OPTIONS="--max_old_space_size=1024"
         #   # see #266, PUBLIC_URL must be without surrounding quotation marks
         #   - PUBLIC_URL=/synapse-admin
-        #   - REACT_APP_SERVER="https://matrix.example.com"
       ports:
         - "8080:80"
       restart: unless-stopped
@@ -96,6 +88,40 @@ or by editing it in the [.env](.env) file. See also the
 
 - browse to http://localhost:8080
 
+### Restricting available homeserver
+
+You can restrict the homeserver(s), so that the user can no longer define it himself.
+
+Edit `config.json` to restrict either to a single homeserver:
+
+```json
+{
+  "restrictBaseUrl": "https://your-matrixs-erver.example.com"
+}
+```
+
+or to a list of homeservers:
+
+```json
+{
+  "restrictBaseUrl": [
+    "https://your-first-matrix-server.example.com",
+    "https://your-second-matrix-server.example.com"
+  ]
+}
+```
+
+The `config.json` can be injected into a Docker container using a bind mount.
+
+```yml
+services:
+  synapse-admin:
+    ...
+    volumes:
+      ./config.json:/app/config.json
+    ...
+```
+
 ## Screenshots
 
 ![Screenshots](./screenshots.jpg)
diff --git a/docker-compose.yml b/docker-compose.yml
index 6e07aa2..6b16162 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,12 +1,10 @@
-version: "3"
-
 services:
   synapse-admin:
     container_name: synapse-admin
     hostname: synapse-admin
     image: awesometechnologies/synapse-admin:latest
     # build:
-    # context: .
+    #   context: .
 
     # to use the docker-compose as standalone without a local repo clone,
     # replace the context definition with this:
@@ -18,9 +16,6 @@ services:
     #   - NODE_OPTIONS="--max_old_space_size=1024"
     # default is .
     #   - PUBLIC_URL=/synapse-admin
-    # You can use a fixed homeserver, so that the user can no longer
-    # define it himself
-    #   - REACT_APP_SERVER="https://matrix.example.com"
     ports:
       - "8080:80"
     restart: unless-stopped
diff --git a/public/config.json b/public/config.json
new file mode 100644
index 0000000..0967ef4
--- /dev/null
+++ b/public/config.json
@@ -0,0 +1 @@
+{}
diff --git a/public/index.html b/public/index.html
index 2b90907..3498b4c 100644
--- a/public/index.html
+++ b/public/index.html
@@ -24,10 +24,110 @@
       Learn how to configure a non-root public URL by running `npm run build`.
     -->
     <title>Synapse-Admin</title>
+    <style>
+      body {
+        margin: 0;
+        padding: 0;
+        font-family: sans-serif;
+      }
+
+      .loader-container {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        flex-direction: column;
+        position: absolute;
+        top: 0;
+        bottom: 0;
+        left: 0;
+        right: 0;
+        background-color: #fafafa;
+      }
+
+      /* CSS Spinner from https://projects.lukehaas.me/css-loaders/ */
+
+      .loader,
+      .loader:before,
+      .loader:after {
+        border-radius: 50%;
+      }
+
+      .loader {
+        color: #283593;
+        font-size: 11px;
+        text-indent: -99999em;
+        margin: 55px auto;
+        position: relative;
+        width: 10em;
+        height: 10em;
+        box-shadow: inset 0 0 0 1em;
+        -webkit-transform: translateZ(0);
+        -ms-transform: translateZ(0);
+        transform: translateZ(0);
+      }
+
+      .loader:before,
+      .loader:after {
+        position: absolute;
+        content: '';
+      }
+
+      .loader:before {
+        width: 5.2em;
+        height: 10.2em;
+        background: #fafafa;
+        border-radius: 10.2em 0 0 10.2em;
+        top: -0.1em;
+        left: -0.1em;
+        -webkit-transform-origin: 5.2em 5.1em;
+        transform-origin: 5.2em 5.1em;
+        -webkit-animation: load2 2s infinite ease 1.5s;
+        animation: load2 2s infinite ease 1.5s;
+      }
+
+      .loader:after {
+        width: 5.2em;
+        height: 10.2em;
+        background: #fafafa;
+        border-radius: 0 10.2em 10.2em 0;
+        top: -0.1em;
+        left: 5.1em;
+        -webkit-transform-origin: 0px 5.1em;
+        transform-origin: 0px 5.1em;
+        -webkit-animation: load2 2s infinite ease;
+        animation: load2 2s infinite ease;
+      }
+
+      @-webkit-keyframes load2 {
+        0% {
+            -webkit-transform: rotate(0deg);
+            transform: rotate(0deg);
+        }
+        100% {
+            -webkit-transform: rotate(360deg);
+            transform: rotate(360deg);
+        }
+      }
+
+      @keyframes load2 {
+        0% {
+            -webkit-transform: rotate(0deg);
+            transform: rotate(0deg);
+        }
+        100% {
+            -webkit-transform: rotate(360deg);
+            transform: rotate(360deg);
+        }
+      }
+    </style>
   </head>
   <body>
     <noscript>You need to enable JavaScript to run this app.</noscript>
-    <div id="root"></div>
+    <div id="root">
+      <div class="loader-container">
+        <div class="loader">Loading...</div>
+      </div>
+    </div>
     <!--
       This HTML file is a template.
       If you open it directly in the browser, you will see an empty page.
@@ -46,4 +146,4 @@
       </a>
     </footer>
   </body>
-</html>
\ No newline at end of file
+</html>
diff --git a/src/AppContext.jsx b/src/AppContext.jsx
new file mode 100644
index 0000000..29164ff
--- /dev/null
+++ b/src/AppContext.jsx
@@ -0,0 +1,5 @@
+import { createContext, useContext } from "react";
+
+export const AppContext = createContext({});
+
+export const useAppContext = () => useContext(AppContext);
diff --git a/src/components/LoginPage.jsx b/src/components/LoginPage.jsx
index 4d0497f..02870a8 100644
--- a/src/components/LoginPage.jsx
+++ b/src/components/LoginPage.jsx
@@ -26,6 +26,8 @@ import {
 } from "@mui/material";
 import { styled } from "@mui/material/styles";
 import LockIcon from "@mui/icons-material/Lock";
+
+import { useAppContext } from "../AppContext";
 import {
   getServerVersion,
   getSupportedFeatures,
@@ -92,13 +94,18 @@ const FormBox = styled(Box)(({ theme }) => ({
 const LoginPage = () => {
   const login = useLogin();
   const notify = useNotify();
+  const { restrictBaseUrl } = useAppContext();
+  const allowSingleBaseUrl = typeof restrictBaseUrl === "string";
+  const allowMultipleBaseUrls = Array.isArray(restrictBaseUrl);
+  const allowAnyBaseUrl = !(allowSingleBaseUrl || allowMultipleBaseUrls);
   const [loading, setLoading] = useState(false);
   const [supportPassAuth, setSupportPassAuth] = useState(true);
   const [locale, setLocale] = useLocaleState();
   const locales = useLocales();
   const translate = useTranslate();
-  const base_url = localStorage.getItem("base_url");
-  const cfg_base_url = process.env.REACT_APP_SERVER;
+  const base_url = allowSingleBaseUrl
+    ? restrictBaseUrl
+    : localStorage.getItem("base_url");
   const [ssoBaseUrl, setSSOBaseUrl] = useState("");
   const loginToken = /\?loginToken=([a-zA-Z0-9_-]+)/.exec(window.location.href);
 
@@ -177,15 +184,24 @@ const LoginPage = () => {
     const [matrixVersions, setMatrixVersions] = useState("");
 
     const handleUsernameChange = _ => {
-      if (formData.base_url || cfg_base_url) return;
+      if (formData.base_url || allowSingleBaseUrl) return;
       // check if username is a full qualified userId then set base_url accordingly
       const domain = splitMxid(formData.username)?.domain;
       if (domain) {
-        getWellKnownUrl(domain).then(url => form.setValue("base_url", url));
+        getWellKnownUrl(domain).then(url => {
+          if (
+            allowAnyBaseUrl ||
+            (allowMultipleBaseUrls && restrictBaseUrl.includes(url))
+          )
+            form.setValue("base_url", url);
+        });
       }
     };
 
     useEffect(() => {
+      if (formData.base_url === "" && allowMultipleBaseUrls) {
+        form.setValue("base_url", restrictBaseUrl[0]);
+      }
       if (!isValidBaseUrl(formData.base_url)) return;
 
       getServerVersion(formData.base_url)
@@ -215,7 +231,7 @@ const LoginPage = () => {
           setSSOBaseUrl(supportSSO ? formData.base_url : "");
         })
         .catch(() => setSSOBaseUrl(""));
-    }, [formData.base_url]);
+    }, [formData.base_url, form]);
 
     return (
       <>
@@ -224,11 +240,11 @@ const LoginPage = () => {
             autoFocus
             name="username"
             label="ra.auth.username"
+            autoComplete="username"
             disabled={loading || !supportPassAuth}
             onBlur={handleUsernameChange}
             resettable
             fullWidth
-            className="input"
             validate={required()}
           />
         </Box>
@@ -237,10 +253,10 @@ const LoginPage = () => {
             name="password"
             label="ra.auth.password"
             type="password"
+            autoComplete="current-password"
             disabled={loading || !supportPassAuth}
             resettable
             fullWidth
-            className="input"
             validate={required()}
           />
         </Box>
@@ -248,12 +264,21 @@ const LoginPage = () => {
           <TextInput
             name="base_url"
             label="synapseadmin.auth.base_url"
-            disabled={cfg_base_url || loading}
-            resettable
+            select={allowMultipleBaseUrls}
+            autoComplete="url"
+            disabled={loading}
+            readOnly={allowSingleBaseUrl}
+            resettable={allowAnyBaseUrl}
             fullWidth
-            className="input"
             validate={[required(), validateBaseUrl]}
-          />
+          >
+            {allowMultipleBaseUrls &&
+              restrictBaseUrl.map(url => (
+                <MenuItem key={url} value={url}>
+                  {url}
+                </MenuItem>
+              ))}
+          </TextInput>
         </Box>
         <Typography className="serverVersion">{serverVersion}</Typography>
         <Typography className="matrixVersions">{matrixVersions}</Typography>
@@ -263,7 +288,7 @@ const LoginPage = () => {
 
   return (
     <Form
-      defaultValues={{ base_url: cfg_base_url || base_url }}
+      defaultValues={{ base_url: base_url }}
       onSubmit={handleSubmit}
       mode="onTouched"
     >
diff --git a/src/components/LoginPage.test.jsx b/src/components/LoginPage.test.jsx
index a336e2d..8be1a71 100644
--- a/src/components/LoginPage.test.jsx
+++ b/src/components/LoginPage.test.jsx
@@ -1,14 +1,71 @@
 import React from "react";
-import { render } from "@testing-library/react";
+import { render, screen } from "@testing-library/react";
 import { AdminContext } from "react-admin";
 import LoginPage from "./LoginPage";
+import { AppContext } from "../AppContext";
 
 describe("LoginForm", () => {
-  it("renders", () => {
+  it("renders with no restriction to homeserver", () => {
     render(
       <AdminContext>
         <LoginPage />
       </AdminContext>
     );
+
+    screen.getByText("synapseadmin.auth.welcome");
+    screen.getByRole("combobox", { name: "" });
+    screen.getByRole("textbox", { name: "ra.auth.username" });
+    screen.getByText("ra.auth.password");
+    const baseUrlInput = screen.getByRole("textbox", {
+      name: "synapseadmin.auth.base_url",
+    });
+    expect(baseUrlInput.className.split(" ")).not.toContain("Mui-readOnly");
+    screen.getByRole("button", { name: "ra.auth.sign_in" });
+  });
+
+  it("renders with single restricted homeserver", () => {
+    render(
+      <AppContext.Provider
+        value={{ restrictBaseUrl: "https://matrix.example.com" }}
+      >
+        <AdminContext>
+          <LoginPage />
+        </AdminContext>
+      </AppContext.Provider>
+    );
+
+    screen.getByText("synapseadmin.auth.welcome");
+    screen.getByRole("combobox", { name: "" });
+    screen.getByRole("textbox", { name: "ra.auth.username" });
+    screen.getByText("ra.auth.password");
+    const baseUrlInput = screen.getByRole("textbox", {
+      name: "synapseadmin.auth.base_url",
+    });
+    expect(baseUrlInput.className.split(" ")).toContain("Mui-readOnly");
+    screen.getByRole("button", { name: "ra.auth.sign_in" });
+  });
+
+  it("renders with multiple restricted homeservers", async () => {
+    render(
+      <AppContext.Provider
+        value={{
+          restrictBaseUrl: [
+            "https://matrix.example.com",
+            "https://matrix.example.org",
+          ],
+        }}
+      >
+        <AdminContext>
+          <LoginPage />
+        </AdminContext>
+      </AppContext.Provider>
+    );
+
+    screen.getByText("synapseadmin.auth.welcome");
+    screen.getByRole("combobox", { name: "" });
+    screen.getByRole("textbox", { name: "ra.auth.username" });
+    screen.getByText("ra.auth.password");
+    screen.getByRole("combobox", { name: "synapseadmin.auth.base_url" });
+    screen.getByRole("button", { name: "ra.auth.sign_in" });
   });
 });
diff --git a/src/index.jsx b/src/index.jsx
index f08e5b6..d1f8efe 100644
--- a/src/index.jsx
+++ b/src/index.jsx
@@ -1,9 +1,17 @@
 import React from "react";
 import { createRoot } from "react-dom/client";
-import App from "./App";
 
-createRoot(document.getElementById("root")).render(
-  <React.StrictMode>
-    <App />
-  </React.StrictMode>
-);
+import App from "./App";
+import { AppContext } from "./AppContext";
+
+fetch("config.json")
+  .then(res => res.json())
+  .then(props =>
+    createRoot(document.getElementById("root")).render(
+      <React.StrictMode>
+        <AppContext.Provider value={props}>
+          <App />
+        </AppContext.Provider>
+      </React.StrictMode>
+    )
+  );
diff --git a/src/synapse/authProvider.js b/src/synapse/authProvider.js
index 159add5..e05d1ca 100644
--- a/src/synapse/authProvider.js
+++ b/src/synapse/authProvider.js
@@ -3,9 +3,6 @@ import { fetchUtils } from "react-admin";
 const authProvider = {
   // called when the user attempts to log in
   login: async ({ base_url, username, password, loginToken }) => {
-    // force homeserver for protection in case the form is manipulated
-    base_url = process.env.REACT_APP_SERVER || base_url;
-
     console.log("login ");
     const options = {
       method: "POST",