diff --git a/.eslintrc.js b/.eslintrc.js
index d5f0ae1ac..3bac9ed69 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -9,7 +9,6 @@ module.exports = {
     'plugin:import/recommended',
     'plugin:promise/recommended',
     'plugin:jsdoc/recommended',
-    'plugin:prettier/recommended',
   ],
 
   env: {
@@ -63,7 +62,9 @@ module.exports = {
     'consistent-return': 'error',
     'dot-notation': 'error',
     eqeqeq: ['error', 'always', { 'null': 'ignore' }],
+    'indent': ['error', 2],
     'jsx-quotes': ['error', 'prefer-single'],
+    'semi': ['error', 'always'],
     'no-case-declarations': 'off',
     'no-catch-shadow': 'error',
     'no-console': [
diff --git a/app/javascript/mastodon/actions/alerts.js b/app/javascript/mastodon/actions/alerts.js
index 051a9675b..42834146b 100644
--- a/app/javascript/mastodon/actions/alerts.js
+++ b/app/javascript/mastodon/actions/alerts.js
@@ -56,4 +56,4 @@ export const showAlertForError = (error, skipNotFound = false) => {
     title: messages.unexpectedTitle,
     message: messages.unexpectedMessage,
   });
-}
+};
diff --git a/app/javascript/mastodon/actions/importer/normalizer.js b/app/javascript/mastodon/actions/importer/normalizer.js
index e6b361c0c..a72142a86 100644
--- a/app/javascript/mastodon/actions/importer/normalizer.js
+++ b/app/javascript/mastodon/actions/importer/normalizer.js
@@ -104,7 +104,7 @@ export function normalizeStatus(status, normalOldStatus) {
       normalStatus.media_attachments.forEach(item => {
         const oldItem = list.find(i => i.get('id') === item.id);
         if (oldItem && oldItem.get('description') === item.description) {
-          item.translation = oldItem.get('translation')
+          item.translation = oldItem.get('translation');
         }
       });
     }
@@ -137,13 +137,13 @@ export function normalizePoll(poll, normalOldPoll) {
       ...option,
       voted: poll.own_votes && poll.own_votes.includes(index),
       titleHtml: emojify(escapeTextContentForBrowser(option.title), emojiMap),
-    }
+    };
 
     if (normalOldPoll && normalOldPoll.getIn(['options', index, 'title']) === option.title) {
       normalOption.translation = normalOldPoll.getIn(['options', index, 'translation']);
     }
 
-    return normalOption
+    return normalOption;
   });
 
   return normalPoll;
diff --git a/app/javascript/mastodon/components/column.jsx b/app/javascript/mastodon/components/column.jsx
index cf9df3ba2..abc87a57e 100644
--- a/app/javascript/mastodon/components/column.jsx
+++ b/app/javascript/mastodon/components/column.jsx
@@ -22,7 +22,7 @@ export default class Column extends PureComponent {
       scrollable = document.scrollingElement;
     } else {
       scrollable = this.node.querySelector('.scrollable');
-   }
+    }
 
     if (!scrollable) {
       return;
diff --git a/app/javascript/mastodon/components/poll.jsx b/app/javascript/mastodon/components/poll.jsx
index 4304f9acd..2d992d73a 100644
--- a/app/javascript/mastodon/components/poll.jsx
+++ b/app/javascript/mastodon/components/poll.jsx
@@ -132,7 +132,7 @@ class Poll extends ImmutablePureComponent {
 
   handleReveal = () => {
     this.setState({ revealed: true });
-  }
+  };
 
   renderOption (option, optionIndex, showResults) {
     const { poll, lang, disabled, intl } = this.props;
diff --git a/app/javascript/mastodon/components/status.jsx b/app/javascript/mastodon/components/status.jsx
index 4a5ad54a1..49d00ca7c 100644
--- a/app/javascript/mastodon/components/status.jsx
+++ b/app/javascript/mastodon/components/status.jsx
@@ -199,7 +199,7 @@ class Status extends ImmutablePureComponent {
     } else if (attachments.getIn([0, 'type']) === 'audio') {
       return '16 / 9';
     } else {
-      return (attachments.size === 1 && attachments.getIn([0, 'meta', 'small', 'aspect'])) ? attachments.getIn([0, 'meta', 'small', 'aspect']) : '3 / 2'
+      return (attachments.size === 1 && attachments.getIn([0, 'meta', 'small', 'aspect'])) ? attachments.getIn([0, 'meta', 'small', 'aspect']) : '3 / 2';
     }
   }
 
diff --git a/app/javascript/mastodon/features/compose/components/navigation_bar.jsx b/app/javascript/mastodon/features/compose/components/navigation_bar.jsx
index 5af38da43..e842ab1f8 100644
--- a/app/javascript/mastodon/features/compose/components/navigation_bar.jsx
+++ b/app/javascript/mastodon/features/compose/components/navigation_bar.jsx
@@ -20,7 +20,7 @@ export default class NavigationBar extends ImmutablePureComponent {
   };
 
   render () {
-    const username = this.props.account.get('acct')
+    const username = this.props.account.get('acct');
     return (
       <div className='navigation-bar'>
         <Link to={`/@${username}`}>
diff --git a/app/javascript/mastodon/features/compose/components/search.jsx b/app/javascript/mastodon/features/compose/components/search.jsx
index 7e1d8b760..dfbfa98f5 100644
--- a/app/javascript/mastodon/features/compose/components/search.jsx
+++ b/app/javascript/mastodon/features/compose/components/search.jsx
@@ -57,14 +57,14 @@ class Search extends PureComponent {
   };
 
   defaultOptions = [
-    { label: <><mark>has:</mark> <FormattedList type='disjunction' value={['media', 'poll', 'embed']} /></>, action: e => { e.preventDefault(); this._insertText('has:') } },
-    { label: <><mark>is:</mark> <FormattedList type='disjunction' value={['reply', 'sensitive']} /></>, action: e => { e.preventDefault(); this._insertText('is:') } },
-    { label: <><mark>language:</mark> <FormattedMessage id='search_popout.language_code' defaultMessage='ISO language code' /></>, action: e => { e.preventDefault(); this._insertText('language:') } },
-    { label: <><mark>from:</mark> <FormattedMessage id='search_popout.user' defaultMessage='user' /></>, action: e => { e.preventDefault(); this._insertText('from:') } },
-    { label: <><mark>before:</mark> <FormattedMessage id='search_popout.specific_date' defaultMessage='specific date' /></>, action: e => { e.preventDefault(); this._insertText('before:') } },
-    { label: <><mark>during:</mark> <FormattedMessage id='search_popout.specific_date' defaultMessage='specific date' /></>, action: e => { e.preventDefault(); this._insertText('during:') } },
-    { label: <><mark>after:</mark> <FormattedMessage id='search_popout.specific_date' defaultMessage='specific date' /></>, action: e => { e.preventDefault(); this._insertText('after:') } },
-    { label: <><mark>in:</mark> <FormattedList type='disjunction' value={['all', 'library']} /></>, action: e => { e.preventDefault(); this._insertText('in:') } }
+    { label: <><mark>has:</mark> <FormattedList type='disjunction' value={['media', 'poll', 'embed']} /></>, action: e => { e.preventDefault(); this._insertText('has:'); } },
+    { label: <><mark>is:</mark> <FormattedList type='disjunction' value={['reply', 'sensitive']} /></>, action: e => { e.preventDefault(); this._insertText('is:'); } },
+    { label: <><mark>language:</mark> <FormattedMessage id='search_popout.language_code' defaultMessage='ISO language code' /></>, action: e => { e.preventDefault(); this._insertText('language:'); } },
+    { label: <><mark>from:</mark> <FormattedMessage id='search_popout.user' defaultMessage='user' /></>, action: e => { e.preventDefault(); this._insertText('from:'); } },
+    { label: <><mark>before:</mark> <FormattedMessage id='search_popout.specific_date' defaultMessage='specific date' /></>, action: e => { e.preventDefault(); this._insertText('before:'); } },
+    { label: <><mark>during:</mark> <FormattedMessage id='search_popout.specific_date' defaultMessage='specific date' /></>, action: e => { e.preventDefault(); this._insertText('during:'); } },
+    { label: <><mark>after:</mark> <FormattedMessage id='search_popout.specific_date' defaultMessage='specific date' /></>, action: e => { e.preventDefault(); this._insertText('after:'); } },
+    { label: <><mark>in:</mark> <FormattedList type='disjunction' value={['all', 'library']} /></>, action: e => { e.preventDefault(); this._insertText('in:'); } }
   ];
 
   setRef = c => {
diff --git a/app/javascript/mastodon/features/explore/results.jsx b/app/javascript/mastodon/features/explore/results.jsx
index 4c23d6422..a3c6adee9 100644
--- a/app/javascript/mastodon/features/explore/results.jsx
+++ b/app/javascript/mastodon/features/explore/results.jsx
@@ -80,7 +80,7 @@ class Results extends PureComponent {
     }
 
     return null;
-  };
+  }
 
   handleSelectAll = () => {
     const { submittedType, dispatch } = this.props;
@@ -116,7 +116,7 @@ class Results extends PureComponent {
     }
 
     this.setState({ type: 'hashtags' });
-  }
+  };
 
   handleSelectStatuses = () => {
     const { submittedType, dispatch } = this.props;
@@ -128,7 +128,7 @@ class Results extends PureComponent {
     }
 
     this.setState({ type: 'statuses' });
-  }
+  };
 
   handleLoadMoreAccounts = () => this._loadMore('accounts');
   handleLoadMoreStatuses = () => this._loadMore('statuses');
diff --git a/app/javascript/mastodon/features/firehose/index.jsx b/app/javascript/mastodon/features/firehose/index.jsx
index efde58a5c..849ee38f5 100644
--- a/app/javascript/mastodon/features/firehose/index.jsx
+++ b/app/javascript/mastodon/features/firehose/index.jsx
@@ -199,7 +199,7 @@ const Firehose = ({ feedType, multiColumn }) => {
       </Helmet>
     </Column>
   );
-}
+};
 
 Firehose.propTypes = {
   multiColumn: PropTypes.bool,
diff --git a/app/javascript/mastodon/features/interaction_modal/index.jsx b/app/javascript/mastodon/features/interaction_modal/index.jsx
index 2a9fa0e33..69bbd8cd8 100644
--- a/app/javascript/mastodon/features/interaction_modal/index.jsx
+++ b/app/javascript/mastodon/features/interaction_modal/index.jsx
@@ -27,9 +27,9 @@ const mapStateToProps = (state, { accountId }) => ({
 const mapDispatchToProps = (dispatch) => ({
   onSignupClick() {
     dispatch(closeModal({
-        modalType: undefined,
-        ignoreFocus: false,
-      }));
+      modalType: undefined,
+      ignoreFocus: false,
+    }));
     dispatch(openModal({ modalType: 'CLOSED_REGISTRATIONS' }));
   },
 });
@@ -187,7 +187,7 @@ class LoginForm extends React.PureComponent {
 
   setIFrameRef = (iframe) => {
     this.iframeRef = iframe;
-  }
+  };
 
   handleFocus = () => {
     this.setState({ expanded: true });
diff --git a/app/javascript/mastodon/features/reblogs/index.jsx b/app/javascript/mastodon/features/reblogs/index.jsx
index 0c4e6dbb9..9de905790 100644
--- a/app/javascript/mastodon/features/reblogs/index.jsx
+++ b/app/javascript/mastodon/features/reblogs/index.jsx
@@ -45,7 +45,7 @@ class Reblogs extends ImmutablePureComponent {
     if (!this.props.accountIds) {
       this.props.dispatch(fetchReblogs(this.props.params.statusId));
     }
-  };
+  }
 
   handleRefresh = () => {
     this.props.dispatch(fetchReblogs(this.props.params.statusId));
diff --git a/app/javascript/mastodon/features/report/comment.jsx b/app/javascript/mastodon/features/report/comment.jsx
index 98ac4caa0..ca9ea9d26 100644
--- a/app/javascript/mastodon/features/report/comment.jsx
+++ b/app/javascript/mastodon/features/report/comment.jsx
@@ -104,7 +104,7 @@ const Comment = ({ comment, domain, statusIds, isRemote, isSubmitting, selectedD
       </div>
     </>
   );
-}
+};
 
 Comment.propTypes = {
   comment: PropTypes.string.isRequired,
diff --git a/app/javascript/mastodon/features/status/components/detailed_status.jsx b/app/javascript/mastodon/features/status/components/detailed_status.jsx
index 3927aba2f..e590ddb82 100644
--- a/app/javascript/mastodon/features/status/components/detailed_status.jsx
+++ b/app/javascript/mastodon/features/status/components/detailed_status.jsx
@@ -132,7 +132,7 @@ class DetailedStatus extends ImmutablePureComponent {
     } else if (attachments.getIn([0, 'type']) === 'audio') {
       return '16 / 9';
     } else {
-      return (attachments.size === 1 && attachments.getIn([0, 'meta', 'small', 'aspect'])) ? attachments.getIn([0, 'meta', 'small', 'aspect']) : '3 / 2'
+      return (attachments.size === 1 && attachments.getIn([0, 'meta', 'small', 'aspect'])) ? attachments.getIn([0, 'meta', 'small', 'aspect']) : '3 / 2';
     }
   }
 
diff --git a/app/javascript/mastodon/features/ui/components/header.jsx b/app/javascript/mastodon/features/ui/components/header.jsx
index 68484b59a..8c6cd600e 100644
--- a/app/javascript/mastodon/features/ui/components/header.jsx
+++ b/app/javascript/mastodon/features/ui/components/header.jsx
@@ -76,8 +76,8 @@ class Header extends PureComponent {
 
       if (sso_redirect) {
         content = (
-            <a href={sso_redirect} data-method='post' className='button button--block button-tertiary'><FormattedMessage id='sign_in_banner.sso_redirect' defaultMessage='Login or Register' /></a>
-        )
+          <a href={sso_redirect} data-method='post' className='button button--block button-tertiary'><FormattedMessage id='sign_in_banner.sso_redirect' defaultMessage='Login or Register' /></a>
+        );
       } else {
         let signupButton;
 
diff --git a/app/javascript/mastodon/features/ui/components/modal_root.jsx b/app/javascript/mastodon/features/ui/components/modal_root.jsx
index f6de5dad3..46f0dc706 100644
--- a/app/javascript/mastodon/features/ui/components/modal_root.jsx
+++ b/app/javascript/mastodon/features/ui/components/modal_root.jsx
@@ -117,7 +117,7 @@ export default class ModalRoot extends PureComponent {
             <BundleContainer fetchComponent={MODAL_COMPONENTS[type]} loading={this.renderLoading(type)} error={this.renderError} renderDelay={200}>
               {(SpecificComponent) => {
                 const ref = typeof SpecificComponent !== 'function' ? this.setModalRef : undefined;
-                return <SpecificComponent {...props} onChangeBackgroundColor={this.setBackgroundColor} onClose={this.handleClose} ref={ref} />
+                return <SpecificComponent {...props} onChangeBackgroundColor={this.setBackgroundColor} onClose={this.handleClose} ref={ref} />;
               }}
             </BundleContainer>
 
diff --git a/app/javascript/mastodon/features/ui/components/sign_in_banner.jsx b/app/javascript/mastodon/features/ui/components/sign_in_banner.jsx
index d5f0c00dc..4216f3da3 100644
--- a/app/javascript/mastodon/features/ui/components/sign_in_banner.jsx
+++ b/app/javascript/mastodon/features/ui/components/sign_in_banner.jsx
@@ -25,7 +25,7 @@ const SignInBanner = () => {
         <p><FormattedMessage id='sign_in_banner.text' defaultMessage='Login to follow profiles or hashtags, favorite, share and reply to posts. You can also interact from your account on a different server.' /></p>
         <a href={sso_redirect} data-method='post' className='button button--block button-tertiary'><FormattedMessage id='sign_in_banner.sso_redirect' defaultMessage='Login or Register' /></a>
       </div>
-    )
+    );
   }
 
   if (registrationsOpen) {
diff --git a/app/javascript/packs/application.js b/app/javascript/packs/application.js
index f26321c41..d13388b47 100644
--- a/app/javascript/packs/application.js
+++ b/app/javascript/packs/application.js
@@ -1,5 +1,5 @@
 import './public-path';
-import main from "mastodon/main"
+import main from "mastodon/main";
 
 import { start } from '../mastodon/common';
 import { loadLocale } from '../mastodon/locales';
diff --git a/streaming/index.js b/streaming/index.js
index 3565ed278..b3765531c 100644
--- a/streaming/index.js
+++ b/streaming/index.js
@@ -256,7 +256,7 @@ const startServer = async () => {
   CHANNEL_NAMES.forEach(( channel ) => {
     connectedChannels.set({ type: 'websocket', channel }, 0);
     connectedChannels.set({ type: 'eventsource', channel }, 0);
-  })
+  });
 
   // Prime the counters so that we don't loose metrics between restarts.
   // Unfortunately counters don't support the set() API, so instead I'm using
@@ -1296,7 +1296,7 @@ const startServer = async () => {
       log.verbose(request.requestId, 'Subscription error:', err.toString());
       socket.send(JSON.stringify({ error: err.toString() }));
     });
-  }
+  };
 
 
   const removeSubscription = (subscriptions, channelIds, request) => {
@@ -1316,7 +1316,7 @@ const startServer = async () => {
     subscription.stopHeartbeat();
 
     delete subscriptions[channelIds.join(';')];
-  }
+  };
 
   /**
    * @param {WebSocketSession} session
@@ -1336,7 +1336,7 @@ const startServer = async () => {
         socket.send(JSON.stringify({ error: "Error unsubscribing from channel" }));
       }
     });
-  }
+  };
 
   /**
    * @param {WebSocketSession} session
@@ -1414,7 +1414,7 @@ const startServer = async () => {
       const subscriptions = Object.keys(session.subscriptions);
 
       subscriptions.forEach(channelIds => {
-        removeSubscription(session.subscriptions, channelIds.split(';'), req)
+        removeSubscription(session.subscriptions, channelIds.split(';'), req);
       });
 
       // Decrement the metrics for connected clients: