diff --git a/src/GameOptions/ui/RemoteAPIPage.tsx b/src/GameOptions/ui/RemoteAPIPage.tsx
index b46735f1ba..e0056f0cde 100644
--- a/src/GameOptions/ui/RemoteAPIPage.tsx
+++ b/src/GameOptions/ui/RemoteAPIPage.tsx
@@ -1,28 +1,46 @@
 import React, { useState } from "react";
 import { Button, Link, TextField, Tooltip, Typography } from "@mui/material";
 import { GameOptionsPage } from "./GameOptionsPage";
-import { Settings } from "../../Settings/Settings";
+import { isValidConnectionHostname, isValidConnectionPort, Settings } from "../../Settings/Settings";
 import { ConnectionBauble } from "./ConnectionBauble";
 import { isRemoteFileApiConnectionLive, newRemoteFileApiConnection } from "../../RemoteFileAPI/RemoteFileAPI";
 
 export const RemoteAPIPage = (): React.ReactElement => {
+  const [remoteFileApiHostname, setRemoteFileApiHostname] = useState(Settings.RemoteFileApiAddress);
   const [remoteFileApiPort, setRemoteFileApiPort] = useState(Settings.RemoteFileApiPort);
-  const [remoteFileApiAddress, setRemoteFileApiAddress] = useState(Settings.RemoteFileApiAddress);
 
-  function handleRemoteFileApiPortChange(event: React.ChangeEvent<HTMLInputElement>): void {
-    setRemoteFileApiPort(Number(event.target.value));
-    Settings.RemoteFileApiPort = Number(event.target.value);
+  function handleRemoteFileApiHostnameChange(event: React.ChangeEvent<HTMLInputElement>): void {
+    let newValue = event.target.value.trim();
+    // Empty string will be automatically changed to "localhost".
+    if (newValue === "") {
+      newValue = "localhost";
+    }
+    if (!isValidConnectionHostname(newValue)) {
+      return;
+    }
+    setRemoteFileApiHostname(newValue);
+    Settings.RemoteFileApiAddress = newValue;
   }
 
-  function handleRemoteFileApiAddressChange(event: React.ChangeEvent<HTMLInputElement>): void {
-    setRemoteFileApiAddress(String(event.target.value));
-    Settings.RemoteFileApiAddress = String(event.target.value);
+  function handleRemoteFileApiPortChange(event: React.ChangeEvent<HTMLInputElement>): void {
+    let newValue = event.target.value.trim();
+    // Empty string will be automatically changed to "0".
+    if (newValue === "") {
+      newValue = "0";
+    }
+    const port = Number.parseInt(newValue);
+    // Disallow invalid ports but still allow the player to set port to 0. Setting it to 0 means that RFA is disabled.
+    if (port !== 0 && !isValidConnectionPort(port)) {
+      return;
+    }
+    setRemoteFileApiPort(port);
+    Settings.RemoteFileApiPort = port;
   }
 
   return (
     <GameOptionsPage title="Remote API">
       <Typography>
-        These settings control the Remote API for bitburner. This is typically used to write scripts using an external
+        These settings control the Remote API for Bitburner. This is typically used to write scripts using an external
         text editor and then upload files to the home server.
       </Typography>
       <Typography>
@@ -37,18 +55,17 @@ export const RemoteAPIPage = (): React.ReactElement => {
       <Tooltip
         title={
           <Typography>
-            This address is used to connect to a Remote API, please ensure that it matches with your Remote API address.
-            Default localhost.
+            This hostname is used to connect to a Remote API, please ensure that it matches with your Remote API
+            hostname. Default: localhost.
           </Typography>
         }
       >
         <TextField
-          key={"remoteAPIAddress"}
           InputProps={{
-            startAdornment: <Typography>Address:&nbsp;</Typography>,
+            startAdornment: <Typography>Hostname:&nbsp;</Typography>,
           }}
-          value={remoteFileApiAddress}
-          onChange={handleRemoteFileApiAddressChange}
+          value={remoteFileApiHostname}
+          onChange={handleRemoteFileApiHostnameChange}
           placeholder="localhost"
           size={"medium"}
         />
@@ -63,10 +80,9 @@ export const RemoteAPIPage = (): React.ReactElement => {
         }
       >
         <TextField
-          key={"remoteAPIPort"}
           InputProps={{
             startAdornment: (
-              <Typography color={remoteFileApiPort > 0 && remoteFileApiPort <= 65535 ? "success" : "error"}>
+              <Typography color={isValidConnectionPort(remoteFileApiPort) ? "success" : "error"}>
                 Port:&nbsp;
               </Typography>
             ),
diff --git a/src/Settings/Settings.ts b/src/Settings/Settings.ts
index 97cb68991e..c2f2357ab5 100644
--- a/src/Settings/Settings.ts
+++ b/src/Settings/Settings.ts
@@ -4,6 +4,45 @@ import { defaultStyles } from "../Themes/Styles";
 import { CursorStyle, CursorBlinking, WordWrapOptions } from "../ScriptEditor/ui/Options";
 import { defaultMonacoTheme } from "../ScriptEditor/ui/themes";
 
+/**
+ * This function won't be able to catch **all** invalid hostnames, and it's still fine. In order to validate a hostname
+ * properly, we need to import a good validation library or write one by ourselves. I think that it's unnecessary.
+ *
+ * Some invalid hostnames that we don't catch:
+ * - Invalid/missing TLD: "abc".
+ * - Use space character: "a a.com"
+ * - Use non-http schemes in the hostname: "ftp://a.com"
+ * - etc.
+ */
+export function isValidConnectionHostname(hostname: string): boolean {
+  /**
+   * We expect a hostname, but the player may mistakenly put other unexpected things. We will try to catch common mistakes:
+   * - Specify a scheme: http or https.
+   * - Specify a port.
+   * - Specify a pathname or search params.
+   */
+  try {
+    // Check scheme.
+    if (hostname.startsWith("http://") || hostname.startsWith("https://")) {
+      return false;
+    }
+    // Parse to a URL with a default scheme.
+    const url = new URL(`http://${hostname}`);
+    // Check port, pathname, and search params.
+    if (url.port !== "" || url.pathname !== "/" || url.search !== "") {
+      return false;
+    }
+  } catch (e) {
+    console.error(`Invalid hostname: ${hostname}`, e);
+    return false;
+  }
+  return true;
+}
+
+export function isValidConnectionPort(port: number): boolean {
+  return Number.isFinite(port) && port > 0 && port <= 65535;
+}
+
 /** The current options the player has customized to their play style. */
 export const Settings = {
   /** How many servers per page */
@@ -125,5 +164,15 @@ export const Settings = {
     save.EditorTheme && Object.assign(Settings.EditorTheme, save.EditorTheme);
     delete save.theme, save.styles, save.overview, save.EditorTheme;
     Object.assign(Settings, save);
+    /**
+     * The hostname and port of RFA have not been validated properly, so the save data may contain invalid data. In that
+     * case, we set them to the default value.
+     */
+    if (!isValidConnectionHostname(Settings.RemoteFileApiAddress)) {
+      Settings.RemoteFileApiAddress = "localhost";
+    }
+    if (!isValidConnectionPort(Settings.RemoteFileApiPort)) {
+      Settings.RemoteFileApiPort = 0;
+    }
   },
 };