diff --git a/src/common/SmartUrlInput.js b/src/common/SmartUrlInput.js
deleted file mode 100644
index daab8bbf989..00000000000
--- a/src/common/SmartUrlInput.js
+++ /dev/null
@@ -1,97 +0,0 @@
-/* @flow strict-local */
-import React, { useState, useRef, useCallback, useContext } from 'react';
-import type { Node } from 'react';
-import { TextInput, View } from 'react-native';
-import { useFocusEffect } from '@react-navigation/native';
-import type { ViewStyleProp } from 'react-native/Libraries/StyleSheet/StyleSheet';
-
-import type { AppNavigationProp } from '../nav/AppNavigator';
-import { ThemeContext, createStyleSheet, HALF_COLOR } from '../styles';
-
-const styles = createStyleSheet({
-  wrapper: {
-    flexDirection: 'row',
-    opacity: 0.8,
-  },
-  realmInput: {
-    flex: 1,
-    padding: 0,
-    fontSize: 20,
-  },
-});
-
-type Props = $ReadOnly<{|
-  // TODO: Currently this type is acceptable because the only
-  // `navigation` prop we pass to a `SmartUrlInput` instance is the
-  // one from a component on AppNavigator.
-  navigation: AppNavigationProp<>,
-
-  style?: ViewStyleProp,
-  onChangeText: (value: string) => void,
-  onSubmitEditing: () => Promise<void>,
-  enablesReturnKeyAutomatically: boolean,
-|}>;
-
-export default function SmartUrlInput(props: Props): Node {
-  const { style, onChangeText, onSubmitEditing, enablesReturnKeyAutomatically } = props;
-
-  // We should replace the fixme with
-  // `React$ElementRef<typeof TextInput>` when we can. Currently, that
-  // would make `.current` be `any(implicit)`, which we don't want;
-  // this is probably down to bugs in Flow's special support for React.
-  const textInputRef = useRef<$FlowFixMe>();
-
-  const [value, setValue] = useState<string>('');
-
-  const themeContext = useContext(ThemeContext);
-
-  // When the route is focused in the navigation, focus the input.
-  // Otherwise, if you go back to this screen from the auth screen, the
-  // input won't be focused.
-  useFocusEffect(
-    useCallback(() => {
-      if (textInputRef.current) {
-        // Sometimes the effect of this `.focus()` is immediately undone
-        // (the keyboard is closed) by a Keyboard.dismiss() from React
-        // Navigation's internals. Seems like a complex bug, but the symptom
-        // isn't terrible, it just means that on back-navigating to this
-        // screen, sometimes the keyboard flicks open then closed, instead
-        // of just opening. Shrug. See
-        //   https://chat.zulip.org/#narrow/stream/243-mobile-team/topic/realm-input/near/1346690
-        //
-        // `.current` is not type-checked; see definition.
-        textInputRef.current.focus();
-      }
-    }, []),
-  );
-
-  const handleChange = useCallback(
-    (_value: string) => {
-      setValue(_value);
-      onChangeText(_value);
-    },
-    [onChangeText],
-  );
-
-  return (
-    <View style={[styles.wrapper, style]}>
-      <TextInput
-        value={value}
-        placeholder="your-org.zulipchat.com"
-        placeholderTextColor={HALF_COLOR}
-        style={[styles.realmInput, { color: themeContext.color }]}
-        autoFocus
-        autoCorrect={false}
-        autoCapitalize="none"
-        returnKeyType="go"
-        onChangeText={handleChange}
-        blurOnSubmit={false}
-        keyboardType="url"
-        underlineColorAndroid="transparent"
-        onSubmitEditing={onSubmitEditing}
-        enablesReturnKeyAutomatically={enablesReturnKeyAutomatically}
-        ref={textInputRef}
-      />
-    </View>
-  );
-}
diff --git a/src/start/RealmInputScreen.js b/src/start/RealmInputScreen.js
index 61205495136..2189486160a 100644
--- a/src/start/RealmInputScreen.js
+++ b/src/start/RealmInputScreen.js
@@ -1,30 +1,26 @@
 /* @flow strict-local */
-import React, { PureComponent } from 'react';
+import React, { useCallback } from 'react';
 import type { Node } from 'react';
-import { Keyboard } from 'react-native';
+import { Keyboard, View, TextInput } from 'react-native';
+import { useFocusEffect } from '@react-navigation/native';
 
 import type { RouteProp } from '../react-navigation';
 import type { AppNavigationProp } from '../nav/AppNavigator';
 import type { ApiResponseServerSettings } from '../api/settings/getServerSettings';
 import ErrorMsg from '../common/ErrorMsg';
 import ZulipTextIntl from '../common/ZulipTextIntl';
-import SmartUrlInput from '../common/SmartUrlInput';
 import Screen from '../common/Screen';
 import ZulipButton from '../common/ZulipButton';
 import { tryParseUrl } from '../utils/url';
 import * as api from '../api';
+import { ThemeContext } from '../styles/theme';
+import { createStyleSheet, HALF_COLOR } from '../styles';
 
 type Props = $ReadOnly<{|
   navigation: AppNavigationProp<'realm-input'>,
   route: RouteProp<'realm-input', {| initial: boolean | void |}>,
 |}>;
 
-type State = {|
-  realmInputValue: string,
-  error: string | null,
-  progress: boolean,
-|};
-
 const urlFromInputValue = (realmInputValue: string): URL | void => {
   const withScheme = /^https?:\/\//.test(realmInputValue)
     ? realmInputValue
@@ -33,88 +29,126 @@ const urlFromInputValue = (realmInputValue: string): URL | void => {
   return tryParseUrl(withScheme);
 };
 
-export default class RealmInputScreen extends PureComponent<Props, State> {
-  state: State = {
-    progress: false,
-    realmInputValue: '',
-    error: null,
-  };
+export default function RealmInputScreen(props: Props): Node {
+  const { navigation, route } = props;
+
+  const themeContext = React.useContext(ThemeContext);
+
+  const [progress, setProgress] = React.useState(false);
+  const [realmInputValue, setRealmInputValue] = React.useState('');
+  const [error, setError] = React.useState(null);
+
+  const textInputRef = React.useRef<React$ElementRef<typeof TextInput> | null>(null);
 
-  tryRealm: () => Promise<void> = async () => {
-    const { realmInputValue } = this.state;
+  // When the route is focused in the navigation, focus the input.
+  // Otherwise, if you go back to this screen from the auth screen, the
+  // input won't be focused.
+  useFocusEffect(
+    useCallback(() => {
+      if (textInputRef.current) {
+        // Sometimes the effect of this `.focus()` is immediately undone
+        // (the keyboard is closed) by a Keyboard.dismiss() from React
+        // Navigation's internals. Seems like a complex bug, but the symptom
+        // isn't terrible, it just means that on back-navigating to this
+        // screen, sometimes the keyboard flicks open then closed, instead
+        // of just opening. Shrug. See
+        //   https://chat.zulip.org/#narrow/stream/243-mobile-team/topic/realm-input/near/1346690
+        textInputRef.current.focus();
+      }
+    }, []),
+  );
 
+  const tryRealm = React.useCallback(async () => {
     const parsedRealm = urlFromInputValue(realmInputValue);
     if (!parsedRealm) {
-      this.setState({ error: 'Please enter a valid URL' });
+      setError('Please enter a valid URL');
       return;
     }
     if (parsedRealm.username !== '') {
-      this.setState({ error: 'Please enter the server URL, not your email' });
+      setError('Please enter the server URL, not your email');
       return;
     }
 
-    this.setState({
-      progress: true,
-      error: null,
-    });
+    setProgress(true);
+    setError(null);
     try {
       const serverSettings: ApiResponseServerSettings = await api.getServerSettings(parsedRealm);
-      this.props.navigation.push('auth', { serverSettings });
+      navigation.push('auth', { serverSettings });
       Keyboard.dismiss();
     } catch (errorIllTyped) {
       const err: mixed = errorIllTyped; // https://github.com/facebook/flow/issues/2470
-      this.setState({ error: 'Cannot connect to server' });
+      setError('Cannot connect to server');
       /* eslint-disable no-console */
       console.warn('RealmInputScreen: failed to connect to server:', err);
       // $FlowFixMe[incompatible-cast]: assuming caught exception was Error
       console.warn((err: Error).stack);
     } finally {
-      this.setState({ progress: false });
+      setProgress(false);
     }
-  };
+  }, [navigation, realmInputValue]);
 
-  handleRealmChange: string => void = value => this.setState({ realmInputValue: value });
+  const styles = React.useMemo(
+    () =>
+      createStyleSheet({
+        inputWrapper: {
+          flexDirection: 'row',
+          opacity: 0.8,
+          marginTop: 16,
+          marginBottom: 8,
+        },
+        input: {
+          flex: 1,
+          padding: 0,
+          fontSize: 20,
+          color: themeContext.color,
+        },
+        hintText: { paddingLeft: 2, fontSize: 12 },
+        button: { marginTop: 8 },
+      }),
+    [themeContext],
+  );
 
-  render(): Node {
-    const { navigation } = this.props;
-    const { progress, error, realmInputValue } = this.state;
-
-    const styles = {
-      input: { marginTop: 16, marginBottom: 8 },
-      hintText: { paddingLeft: 2, fontSize: 12 },
-      button: { marginTop: 8 },
-    };
-
-    return (
-      <Screen
-        title="Welcome"
-        canGoBack={!this.props.route.params.initial}
-        padding
-        centerContent
-        keyboardShouldPersistTaps="always"
-        shouldShowLoadingBanner={false}
-      >
-        <ZulipTextIntl text="Enter your Zulip server URL:" />
-        <SmartUrlInput
+  return (
+    <Screen
+      title="Welcome"
+      canGoBack={!route.params.initial}
+      padding
+      centerContent
+      keyboardShouldPersistTaps="always"
+      shouldShowLoadingBanner={false}
+    >
+      <ZulipTextIntl text="Enter your Zulip server URL:" />
+      <View style={styles.inputWrapper}>
+        <TextInput
+          value={realmInputValue}
+          placeholder="your-org.zulipchat.com"
+          placeholderTextColor={HALF_COLOR}
           style={styles.input}
-          navigation={navigation}
-          onChangeText={this.handleRealmChange}
-          onSubmitEditing={this.tryRealm}
+          autoFocus
+          autoCorrect={false}
+          autoCapitalize="none"
+          returnKeyType="go"
+          onChangeText={setRealmInputValue}
+          blurOnSubmit={false}
+          keyboardType="url"
+          underlineColorAndroid="transparent"
+          onSubmitEditing={tryRealm}
           enablesReturnKeyAutomatically
+          ref={textInputRef}
         />
-        {error !== null ? (
-          <ErrorMsg error={error} />
-        ) : (
-          <ZulipTextIntl text="e.g. zulip.example.com" style={styles.hintText} />
-        )}
-        <ZulipButton
-          style={styles.button}
-          text="Enter"
-          progress={progress}
-          onPress={this.tryRealm}
-          disabled={urlFromInputValue(realmInputValue) === undefined}
-        />
-      </Screen>
-    );
-  }
+      </View>
+      {error !== null ? (
+        <ErrorMsg error={error} />
+      ) : (
+        <ZulipTextIntl text="e.g. zulip.example.com" style={styles.hintText} />
+      )}
+      <ZulipButton
+        style={styles.button}
+        text="Enter"
+        progress={progress}
+        onPress={tryRealm}
+        disabled={urlFromInputValue(realmInputValue) === undefined}
+      />
+    </Screen>
+  );
 }