diff --git a/app/javascript/mastodon/actions/compose.js b/app/javascript/mastodon/actions/compose.js
index f487545444..06335f9fbf 100644
--- a/app/javascript/mastodon/actions/compose.js
+++ b/app/javascript/mastodon/actions/compose.js
@@ -99,7 +99,7 @@ export const ensureComposeIsVisible = (getState) => {
 
 export function setComposeToStatus(status, text, spoiler_text) {
   return (dispatch, getState) => {
-    const maxOptions = getState().server.getIn(['server', 'configuration', 'polls', 'max_options']);
+    const maxOptions = getState().server.server.item?.configuration.polls.max_options;
 
     dispatch({
       type: COMPOSE_SET_STATUS,
diff --git a/app/javascript/mastodon/actions/server.js b/app/javascript/mastodon/actions/server.js
deleted file mode 100644
index c291eb772a..0000000000
--- a/app/javascript/mastodon/actions/server.js
+++ /dev/null
@@ -1,139 +0,0 @@
-import api from '../api';
-
-import { importFetchedAccount } from './importer';
-
-export const SERVER_FETCH_REQUEST = 'Server_FETCH_REQUEST';
-export const SERVER_FETCH_SUCCESS = 'Server_FETCH_SUCCESS';
-export const SERVER_FETCH_FAIL    = 'Server_FETCH_FAIL';
-
-export const SERVER_TRANSLATION_LANGUAGES_FETCH_REQUEST = 'SERVER_TRANSLATION_LANGUAGES_FETCH_REQUEST';
-export const SERVER_TRANSLATION_LANGUAGES_FETCH_SUCCESS = 'SERVER_TRANSLATION_LANGUAGES_FETCH_SUCCESS';
-export const SERVER_TRANSLATION_LANGUAGES_FETCH_FAIL    = 'SERVER_TRANSLATION_LANGUAGES_FETCH_FAIL';
-
-export const EXTENDED_DESCRIPTION_REQUEST = 'EXTENDED_DESCRIPTION_REQUEST';
-export const EXTENDED_DESCRIPTION_SUCCESS = 'EXTENDED_DESCRIPTION_SUCCESS';
-export const EXTENDED_DESCRIPTION_FAIL    = 'EXTENDED_DESCRIPTION_FAIL';
-
-export const SERVER_DOMAIN_BLOCKS_FETCH_REQUEST = 'SERVER_DOMAIN_BLOCKS_FETCH_REQUEST';
-export const SERVER_DOMAIN_BLOCKS_FETCH_SUCCESS = 'SERVER_DOMAIN_BLOCKS_FETCH_SUCCESS';
-export const SERVER_DOMAIN_BLOCKS_FETCH_FAIL    = 'SERVER_DOMAIN_BLOCKS_FETCH_FAIL';
-
-export const fetchServer = () => (dispatch, getState) => {
-  if (getState().getIn(['server', 'server', 'isLoading'])) {
-    return;
-  }
-
-  dispatch(fetchServerRequest());
-
-  api()
-    .get('/api/v2/instance').then(({ data }) => {
-      // Only import the account if it doesn't already exist,
-      // because the API is cached even for logged in users.
-      const account = data.contact.account;
-      if (account) {
-        const existingAccount = getState().getIn(['accounts', account.id]);
-        if (!existingAccount) {
-          dispatch(importFetchedAccount(account));
-        }
-      }
-      dispatch(fetchServerSuccess(data));
-    }).catch(err => dispatch(fetchServerFail(err)));
-};
-
-const fetchServerRequest = () => ({
-  type: SERVER_FETCH_REQUEST,
-});
-
-const fetchServerSuccess = server => ({
-  type: SERVER_FETCH_SUCCESS,
-  server,
-});
-
-const fetchServerFail = error => ({
-  type: SERVER_FETCH_FAIL,
-  error,
-});
-
-export const fetchServerTranslationLanguages = () => (dispatch) => {
-  dispatch(fetchServerTranslationLanguagesRequest());
-
-  api()
-    .get('/api/v1/instance/translation_languages').then(({ data }) => {
-      dispatch(fetchServerTranslationLanguagesSuccess(data));
-    }).catch(err => dispatch(fetchServerTranslationLanguagesFail(err)));
-};
-
-const fetchServerTranslationLanguagesRequest = () => ({
-  type: SERVER_TRANSLATION_LANGUAGES_FETCH_REQUEST,
-});
-
-const fetchServerTranslationLanguagesSuccess = translationLanguages => ({
-  type: SERVER_TRANSLATION_LANGUAGES_FETCH_SUCCESS,
-  translationLanguages,
-});
-
-const fetchServerTranslationLanguagesFail = error => ({
-  type: SERVER_TRANSLATION_LANGUAGES_FETCH_FAIL,
-  error,
-});
-
-export const fetchExtendedDescription = () => (dispatch, getState) => {
-  if (getState().getIn(['server', 'extendedDescription', 'isLoading'])) {
-    return;
-  }
-
-  dispatch(fetchExtendedDescriptionRequest());
-
-  api()
-    .get('/api/v1/instance/extended_description')
-    .then(({ data }) => dispatch(fetchExtendedDescriptionSuccess(data)))
-    .catch(err => dispatch(fetchExtendedDescriptionFail(err)));
-};
-
-const fetchExtendedDescriptionRequest = () => ({
-  type: EXTENDED_DESCRIPTION_REQUEST,
-});
-
-const fetchExtendedDescriptionSuccess = description => ({
-  type: EXTENDED_DESCRIPTION_SUCCESS,
-  description,
-});
-
-const fetchExtendedDescriptionFail = error => ({
-  type: EXTENDED_DESCRIPTION_FAIL,
-  error,
-});
-
-export const fetchDomainBlocks = () => (dispatch, getState) => {
-  if (getState().getIn(['server', 'domainBlocks', 'isLoading'])) {
-    return;
-  }
-
-  dispatch(fetchDomainBlocksRequest());
-
-  api()
-    .get('/api/v1/instance/domain_blocks')
-    .then(({ data }) => dispatch(fetchDomainBlocksSuccess(true, data)))
-    .catch(err => {
-      if (err.response.status === 404) {
-        dispatch(fetchDomainBlocksSuccess(false, []));
-      } else {
-        dispatch(fetchDomainBlocksFail(err));
-      }
-    });
-};
-
-const fetchDomainBlocksRequest = () => ({
-  type: SERVER_DOMAIN_BLOCKS_FETCH_REQUEST,
-});
-
-const fetchDomainBlocksSuccess = (isAvailable, blocks) => ({
-  type: SERVER_DOMAIN_BLOCKS_FETCH_SUCCESS,
-  isAvailable,
-  blocks,
-});
-
-const fetchDomainBlocksFail = error => ({
-  type: SERVER_DOMAIN_BLOCKS_FETCH_FAIL,
-  error,
-});
diff --git a/app/javascript/mastodon/actions/server.ts b/app/javascript/mastodon/actions/server.ts
new file mode 100644
index 0000000000..4e4795c123
--- /dev/null
+++ b/app/javascript/mastodon/actions/server.ts
@@ -0,0 +1,34 @@
+import {
+  apiGetInstance,
+  apiGetExtendedDescription,
+  apiGetDomainBlocks,
+  apiGetTranslationLanguages,
+} from 'mastodon/api/instance';
+import { createDataLoadingThunk } from 'mastodon/store/typed_functions';
+
+import { importFetchedAccount } from './importer';
+
+export const fetchServer = createDataLoadingThunk(
+  'server/fetch',
+  () => apiGetInstance(),
+  (instance, { dispatch }) => {
+    if (instance.contact.account) {
+      dispatch(importFetchedAccount(instance.contact.account));
+    }
+  },
+);
+
+export const fetchExtendedDescription = createDataLoadingThunk(
+  'server/extended_description',
+  () => apiGetExtendedDescription(),
+);
+
+export const fetchServerTranslationLanguages = createDataLoadingThunk(
+  'server/translation_languages',
+  () => apiGetTranslationLanguages(),
+);
+
+export const fetchDomainBlocks = createDataLoadingThunk(
+  'server/domain_blocks',
+  () => apiGetDomainBlocks(),
+);
diff --git a/app/javascript/mastodon/actions/statuses.js b/app/javascript/mastodon/actions/statuses.js
index d714ed3849..109d676bfb 100644
--- a/app/javascript/mastodon/actions/statuses.js
+++ b/app/javascript/mastodon/actions/statuses.js
@@ -111,7 +111,7 @@ export function fetchStatusFail(id, error, skipLoading, parentQuotePostId) {
 
 export function redraft(status, raw_text, quoted_status_id = null) {
   return (dispatch, getState) => {
-    const maxOptions = getState().server.getIn(['server', 'configuration', 'polls', 'max_options']);
+    const maxOptions = getState().server.server.item?.configuration.polls.max_options;
 
     dispatch({
       type: REDRAFT,
diff --git a/app/javascript/mastodon/api/instance.ts b/app/javascript/mastodon/api/instance.ts
index 764e8daab2..b3f04f12d1 100644
--- a/app/javascript/mastodon/api/instance.ts
+++ b/app/javascript/mastodon/api/instance.ts
@@ -2,6 +2,10 @@ import { apiRequestGet } from 'mastodon/api';
 import type {
   ApiTermsOfServiceJSON,
   ApiPrivacyPolicyJSON,
+  ApiInstanceJSON,
+  ApiExtendedDescriptionJSON,
+  ApiTranslationLanguagesJSON,
+  ApiDomainBlockJSON,
 } from 'mastodon/api_types/instance';
 
 export const apiGetTermsOfService = (version?: string) =>
@@ -13,3 +17,17 @@ export const apiGetTermsOfService = (version?: string) =>
 
 export const apiGetPrivacyPolicy = () =>
   apiRequestGet<ApiPrivacyPolicyJSON>('v1/instance/privacy_policy');
+
+export const apiGetInstance = () =>
+  apiRequestGet<ApiInstanceJSON>('v2/instance');
+
+export const apiGetExtendedDescription = () =>
+  apiRequestGet<ApiExtendedDescriptionJSON>('v1/instance/extended_description');
+
+export const apiGetTranslationLanguages = () =>
+  apiRequestGet<ApiTranslationLanguagesJSON>(
+    'v1/instance/translation_languages',
+  );
+
+export const apiGetDomainBlocks = () =>
+  apiRequestGet<ApiDomainBlockJSON[]>('v1/instance/domain_blocks');
diff --git a/app/javascript/mastodon/api_types/instance.ts b/app/javascript/mastodon/api_types/instance.ts
index 3a29684b70..361dade4c7 100644
--- a/app/javascript/mastodon/api_types/instance.ts
+++ b/app/javascript/mastodon/api_types/instance.ts
@@ -1,3 +1,5 @@
+import type { ApiAccountJSON } from './accounts';
+
 export interface ApiTermsOfServiceJSON {
   effective_date: string;
   effective: boolean;
@@ -9,3 +11,136 @@ export interface ApiPrivacyPolicyJSON {
   updated_at: string;
   content: string;
 }
+
+interface ApiBaseRuleJSON {
+  text: string;
+  hint: string;
+}
+
+export interface ApiRuleJSON {
+  id: string;
+  text: string;
+  hint: string;
+  translations?: Record<string, ApiBaseRuleJSON>;
+}
+
+export interface ApiExtendedDescriptionJSON {
+  updated_at: string;
+  content: string;
+}
+
+export interface ApiDomainBlockJSON {
+  domain: string;
+  digest: string;
+  severity: string;
+  comment: string;
+}
+
+export type ApiTranslationLanguagesJSON = Record<string, string[]>;
+
+export interface ApiInstanceJSON {
+  domain: string;
+  title: string;
+  version: string;
+  source_url: string;
+  description: string;
+  languages: string[];
+  usage: {
+    users: {
+      active_month: number;
+    };
+  };
+  thumbnail: {
+    url: string;
+    blurhash?: string;
+    description: string;
+    versions?: Record<string, string>;
+  };
+  contact: {
+    email: string | null;
+    account: ApiAccountJSON | null;
+  };
+  api_versions: {
+    mastodon: number;
+  };
+  registrations: {
+    enabled: boolean;
+    approval_required: boolean;
+    reason_required: boolean | null;
+    message: string | null;
+    min_age: string | null;
+    url: string | null;
+  };
+  rules: ApiRuleJSON[];
+  configuration: {
+    urls: {
+      streaming: string;
+      status: string | null;
+      about: string;
+      privacy_policy: string | null;
+      terms_of_service: string | null;
+    };
+
+    vapid: {
+      public_key: string;
+    };
+
+    accounts: {
+      max_display_name_length: number;
+      max_note_length: number;
+      max_avatar_description_length: number;
+      max_header_description_length: number;
+      max_featured_tags: number;
+      max_pinned_statuses: number;
+      max_profile_fields: number;
+      profile_field_name_limit: number;
+      profile_field_value_limit: number;
+    };
+
+    statuses: {
+      max_characters: number;
+      max_media_attachments: number;
+      characters_reserved_per_url: number;
+    };
+
+    media_attachments: {
+      description_limit: number;
+      image_matrix_limit: number;
+      image_size_limit: number;
+      supported_mime_types: string[];
+      video_frame_rate_limit: number;
+      video_matrix_limit: number;
+      video_size_limit: number;
+    };
+
+    polls: {
+      max_options: number;
+      max_characters_per_option: number;
+      min_expiration: number;
+      max_expiration: number;
+    };
+
+    translation: {
+      enabled: boolean;
+    };
+
+    timeline_access: {
+      live_feeds: {
+        local: string;
+        remote: string;
+      };
+
+      hashtag_feeds: {
+        local: string;
+        remote: string;
+      };
+
+      trending_link_feeds: {
+        local: string;
+        remote: string;
+      };
+    };
+
+    limited_federation: boolean;
+  };
+}
diff --git a/app/javascript/mastodon/components/server_banner.jsx b/app/javascript/mastodon/components/server_banner.jsx
index 939a92b281..b5484a1a37 100644
--- a/app/javascript/mastodon/components/server_banner.jsx
+++ b/app/javascript/mastodon/components/server_banner.jsx
@@ -22,7 +22,7 @@ const messages = defineMessages({
 });
 
 const mapStateToProps = state => ({
-  server: state.getIn(['server', 'server']),
+  server: state.server.server,
 });
 
 class ServerBanner extends PureComponent {
@@ -40,7 +40,7 @@ class ServerBanner extends PureComponent {
 
   render () {
     const { server, intl } = this.props;
-    const isLoading = server.get('isLoading');
+    const isLoading = server.isLoading;
 
     return (
       <div className='server-banner'>
@@ -50,8 +50,8 @@ class ServerBanner extends PureComponent {
 
         <NavLink to='/about'>
           <ServerHeroImage
-            blurhash={server.getIn(['thumbnail', 'blurhash'])}
-            src={server.getIn(['thumbnail', 'url'])}
+            blurhash={server.item?.thumbnail.blurhash}
+            src={server.item?.thumbnail.url}
             alt={intl.formatMessage(messages.aboutThisServer)}
             className='server-banner__hero'
           />
@@ -66,14 +66,14 @@ class ServerBanner extends PureComponent {
               <br />
               <Skeleton width='70%' />
             </>
-          ) : server.get('description')}
+          ) : server.item?.description}
         </div>
 
         <div className='server-banner__meta'>
           <div className='server-banner__meta__column'>
             <h4><FormattedMessage id='server_banner.administered_by' defaultMessage='Administered by:' /></h4>
 
-            <Account id={server.getIn(['contact', 'account', 'id'])} size={36} minimal />
+            <Account id={server.item?.contact.account?.id} size={36} minimal />
           </div>
 
           <div className='server-banner__meta__column'>
@@ -87,7 +87,7 @@ class ServerBanner extends PureComponent {
               </>
             ) : (
               <>
-                <strong className='server-banner__number'><ShortNumber value={server.getIn(['usage', 'users', 'active_month'])} /></strong>
+                <strong className='server-banner__number'><ShortNumber value={server.item?.usage.users.active_month} /></strong>
                 <br />
                 <span className='server-banner__number-label' title={intl.formatMessage(messages.aboutActiveUsers)}><FormattedMessage id='server_banner.active_users' defaultMessage='active users' /></span>
               </>
diff --git a/app/javascript/mastodon/components/status_content.jsx b/app/javascript/mastodon/components/status_content.jsx
index 920bdbf14e..2b61499d65 100644
--- a/app/javascript/mastodon/components/status_content.jsx
+++ b/app/javascript/mastodon/components/status_content.jsx
@@ -69,7 +69,7 @@ class TranslateButton extends PureComponent {
 }
 
 const mapStateToProps = state => ({
-  languages: state.getIn(['server', 'translationLanguages', 'items']),
+  languages: state.server.translationLanguages.items,
 });
 
 class StatusContent extends PureComponent {
diff --git a/app/javascript/mastodon/features/about/components/rules.tsx b/app/javascript/mastodon/features/about/components/rules.tsx
index 52339329fe..e8bde723ca 100644
--- a/app/javascript/mastodon/features/about/components/rules.tsx
+++ b/app/javascript/mastodon/features/about/components/rules.tsx
@@ -5,7 +5,6 @@ import type { IntlShape } from 'react-intl';
 import { defineMessages, FormattedMessage, useIntl } from 'react-intl';
 
 import { createSelector } from '@reduxjs/toolkit';
-import type { List as ImmutableList } from 'immutable';
 
 import type { SelectItem } from '@/mastodon/components/dropdown_selector';
 import { Select } from '@/mastodon/components/form_fields';
@@ -123,14 +122,13 @@ export const RulesSection: FC<RulesSectionProps> = ({ isLoading = false }) => {
 };
 
 const selectRules = (state: RootState) => {
-  const rules = state.server.getIn([
-    'server',
-    'rules',
-  ]) as ImmutableList<Rule> | null;
+  const rules = state.server.server.item?.rules;
+
   if (!rules) {
     return [];
   }
-  return rules.toJS() as Rule[];
+
+  return rules;
 };
 
 const rulesSelector = createSelector(
diff --git a/app/javascript/mastodon/features/about/index.jsx b/app/javascript/mastodon/features/about/index.jsx
index 9814032cac..4c1ee5254a 100644
--- a/app/javascript/mastodon/features/about/index.jsx
+++ b/app/javascript/mastodon/features/about/index.jsx
@@ -41,10 +41,10 @@ const severityMessages = {
 };
 
 const mapStateToProps = state => ({
-  server: state.getIn(['server', 'server']),
+  server: state.server.server,
   locale: state.getIn(['meta', 'locale']),
-  extendedDescription: state.getIn(['server', 'extendedDescription']),
-  domainBlocks: state.getIn(['server', 'domainBlocks']),
+  extendedDescription: state.server.extendedDescription,
+  domainBlocks: state.server.domainBlocks,
 });
 
 class About extends PureComponent {
@@ -76,7 +76,7 @@ class About extends PureComponent {
 
   render () {
     const { multiColumn, intl, server, extendedDescription, domainBlocks, locale } = this.props;
-    const isLoading = server.get('isLoading');
+    const isLoading = server.isLoading;
 
     return (
       <Column bindToDocument={!multiColumn} label={intl.formatMessage(messages.title)}>
@@ -84,13 +84,13 @@ class About extends PureComponent {
           <div className='about__header'>
             <ServerHeroImage
               withAltBadge
-              alt={server.getIn(['thumbnail', 'description']) ?? ''}
-              blurhash={server.getIn(['thumbnail', 'blurhash'])}
-              src={server.getIn(['thumbnail', 'url'])}
-              srcSet={server.getIn(['thumbnail', 'versions'])?.map((value, key) => `${value} ${key.replace('@', '')}`).join(', ')}
+              alt={server.item?.thumbnail.description ?? ''}
+              blurhash={server.item?.thumbnail.blurhash}
+              src={server.item?.thumbnail.url}
+              srcSet={Object.keys(server.item?.thumbnail.versions ?? {}).map((key) => `${server.item?.thumbnail.versions && server.item.thumbnail.versions[key]} ${key.replace('@', '')}`).join(', ')}
               className='about__header__hero'
             />
-            <h1>{isLoading ? <Skeleton width='10ch' /> : server.get('domain')}</h1>
+            <h1>{isLoading ? <Skeleton width='10ch' /> : server.domain}</h1>
             <p><FormattedMessage id='about.powered_by' defaultMessage='Decentralized social media powered by {mastodon}' values={{ mastodon: <a href='https://joinmastodon.org' className='about__mail' target='_blank' rel='noopener'>Mastodon</a> }} /></p>
           </div>
 
@@ -98,7 +98,7 @@ class About extends PureComponent {
             <div className='about__meta__column'>
               <h4><FormattedMessage id='server_banner.administered_by' defaultMessage='Administered by:' /></h4>
 
-              <Account id={server.getIn(['contact', 'account', 'id'])} size={36} minimal />
+              <Account id={server.item?.contact?.account?.id} size={36} minimal />
             </div>
 
             <hr className='about__meta__divider' />
@@ -106,12 +106,12 @@ class About extends PureComponent {
             <div className='about__meta__column'>
               <h4><FormattedMessage id='about.contact' defaultMessage='Contact:' /></h4>
 
-              {isLoading ? <Skeleton width='10ch' /> : <a className='about__mail' href={`mailto:${server.getIn(['contact', 'email'])}`}>{server.getIn(['contact', 'email'])}</a>}
+              {isLoading ? <Skeleton width='10ch' /> : <a className='about__mail' href={`mailto:${server.item?.contact?.email}`}>{server.item?.contact?.email}</a>}
             </div>
           </div>
 
           <Section open title={intl.formatMessage(messages.title)}>
-            {extendedDescription.get('isLoading') ? (
+            {extendedDescription.isLoading ? (
               <>
                 <Skeleton width='100%' />
                 <br />
@@ -121,10 +121,10 @@ class About extends PureComponent {
                 <br />
                 <Skeleton width='70%' />
               </>
-            ) : (extendedDescription.get('content')?.length > 0 ? (
+            ) : (extendedDescription.item?.content?.length > 0 ? (
               <div
                 className='prose'
-                dangerouslySetInnerHTML={{ __html: extendedDescription.get('content') }}
+                dangerouslySetInnerHTML={{ __html: extendedDescription.item?.content }}
               />
             ) : (
               <p><FormattedMessage id='about.not_available' defaultMessage='This information has not been made available on this server.' /></p>
@@ -134,26 +134,26 @@ class About extends PureComponent {
           <RulesSection />
 
           <Section title={intl.formatMessage(messages.blocks)} onOpen={this.handleDomainBlocksOpen}>
-            {domainBlocks.get('isLoading') ? (
+            {domainBlocks.isLoading ? (
               <>
                 <Skeleton width='100%' />
                 <br />
                 <Skeleton width='70%' />
               </>
-            ) : (domainBlocks.get('isAvailable') ? (
+            ) : (domainBlocks.isAvailable ? (
               <>
                 <p><FormattedMessage id='about.domain_blocks.preamble' defaultMessage='Mastodon generally allows you to view content from and interact with users from any other server in the fediverse. These are the exceptions that have been made on this particular server.' /></p>
 
-                {domainBlocks.get('items').size > 0 && (
+                {domainBlocks.items.length > 0 && (
                   <div className='about__domain-blocks'>
-                    {domainBlocks.get('items').map(block => (
-                      <div className='about__domain-blocks__domain' key={block.get('domain')}>
+                    {domainBlocks.items.map(block => (
+                      <div className='about__domain-blocks__domain' key={block.domain}>
                         <div className='about__domain-blocks__domain__header'>
-                          <h6><span title={`SHA-256: ${block.get('digest')}`}>{block.get('domain')}</span></h6>
-                          <span className='about__domain-blocks__domain__type' title={intl.formatMessage(severityMessages[block.get('severity')].explanation)}>{intl.formatMessage(severityMessages[block.get('severity')].title)}</span>
+                          <h6><span title={`SHA-256: ${block.digest}`}>{block.domain}</span></h6>
+                          <span className='about__domain-blocks__domain__type' title={intl.formatMessage(severityMessages[block.severity].explanation)}>{intl.formatMessage(severityMessages[block.severity].title)}</span>
                         </div>
 
-                        <p>{(block.get('comment') || '').length > 0 ? block.get('comment') : <FormattedMessage id='about.domain_blocks.no_reason_available' defaultMessage='Reason not available' />}</p>
+                        <p>{(block.comment ?? '').length > 0 ? block.comment : <FormattedMessage id='about.domain_blocks.no_reason_available' defaultMessage='Reason not available' />}</p>
                       </div>
                     ))}
                   </div>
diff --git a/app/javascript/mastodon/features/account_edit/featured_tags.tsx b/app/javascript/mastodon/features/account_edit/featured_tags.tsx
index 5fc602208d..fedfde62e3 100644
--- a/app/javascript/mastodon/features/account_edit/featured_tags.tsx
+++ b/app/javascript/mastodon/features/account_edit/featured_tags.tsx
@@ -37,10 +37,7 @@ const selectTags = createAppSelector(
   [
     (state) => state.profileEdit,
     (state) =>
-      state.server.getIn(
-        ['server', 'accounts', 'max_featured_tags'],
-        10,
-      ) as number,
+      state.server.server.item?.configuration.accounts.max_featured_tags ?? 0,
   ],
   (profileEdit, maxTags) => ({
     tags: profileEdit.profile?.featuredTags ?? [],
diff --git a/app/javascript/mastodon/features/account_edit/index.tsx b/app/javascript/mastodon/features/account_edit/index.tsx
index 0199c3efa4..d00473043e 100644
--- a/app/javascript/mastodon/features/account_edit/index.tsx
+++ b/app/javascript/mastodon/features/account_edit/index.tsx
@@ -133,12 +133,7 @@ export const AccountEdit: FC = () => {
 
   const maxFieldCount = useAppSelector(
     (state) =>
-      (state.server.getIn([
-        'server',
-        'configuration',
-        'accounts',
-        'max_profile_fields',
-      ]) as number | undefined) ?? 4,
+      state.server.server.item?.configuration.accounts.max_profile_fields ?? 4,
   );
 
   const handleOpenModal = useCallback(
diff --git a/app/javascript/mastodon/features/account_edit/modals/bio_modal.tsx b/app/javascript/mastodon/features/account_edit/modals/bio_modal.tsx
index ff4febeebb..8d286dedce 100644
--- a/app/javascript/mastodon/features/account_edit/modals/bio_modal.tsx
+++ b/app/javascript/mastodon/features/account_edit/modals/bio_modal.tsx
@@ -36,13 +36,7 @@ export const BioModal: FC<BaseConfirmationModalProps> = ({ onClose }) => {
   );
   const [newBio, setNewBio] = useState(bio ?? '');
   const maxLength = useAppSelector(
-    (state) =>
-      state.server.getIn([
-        'server',
-        'configuration',
-        'accounts',
-        'max_note_length',
-      ]) as number | undefined,
+    (state) => state.server.server.item?.configuration.accounts.max_note_length,
   );
 
   const dispatch = useAppDispatch();
diff --git a/app/javascript/mastodon/features/account_edit/modals/fields_modals.tsx b/app/javascript/mastodon/features/account_edit/modals/fields_modals.tsx
index 98324cf4dd..9fc26ac525 100644
--- a/app/javascript/mastodon/features/account_edit/modals/fields_modals.tsx
+++ b/app/javascript/mastodon/features/account_edit/modals/fields_modals.tsx
@@ -9,8 +9,6 @@ import type { FC, FocusEventHandler } from 'react';
 
 import { defineMessages, FormattedMessage, useIntl } from 'react-intl';
 
-import type { Map as ImmutableMap } from 'immutable';
-
 import { closeModal } from '@/mastodon/actions/modal';
 import { Button } from '@/mastodon/components/button';
 import type { FieldStatus } from '@/mastodon/components/form_fields';
@@ -97,15 +95,10 @@ const messages = defineMessages({
 // We have two different values- the hard limit set by the server,
 // and the soft limit for mobile display.
 const selectFieldLimits = createAppSelector(
-  [
-    (state) =>
-      state.server.getIn(['server', 'configuration', 'accounts']) as
-        | ImmutableMap<string, number>
-        | undefined,
-  ],
+  [(state) => state.server.server.item?.configuration.accounts],
   (accounts) => ({
-    nameLimit: accounts?.get('profile_field_name_limit'),
-    valueLimit: accounts?.get('profile_field_value_limit'),
+    nameLimit: accounts?.profile_field_name_limit,
+    valueLimit: accounts?.profile_field_value_limit,
   }),
 );
 
diff --git a/app/javascript/mastodon/features/account_edit/modals/image_alt.tsx b/app/javascript/mastodon/features/account_edit/modals/image_alt.tsx
index d9d014f792..61f5d5ffdd 100644
--- a/app/javascript/mastodon/features/account_edit/modals/image_alt.tsx
+++ b/app/javascript/mastodon/features/account_edit/modals/image_alt.tsx
@@ -84,15 +84,8 @@ export const ImageAltTextField: FC<{
 }> = ({ imageSrc, altText, onChange, hideTip }) => {
   const altLimit = useAppSelector(
     (state) =>
-      state.server.getIn(
-        [
-          'server',
-          'configuration',
-          'accounts',
-          'max_header_description_length',
-        ],
-        150,
-      ) as number,
+      state.server.server.item?.configuration.accounts
+        .max_header_description_length ?? 0,
   );
 
   const handleChange: ChangeEventHandler<HTMLTextAreaElement> = useCallback(
diff --git a/app/javascript/mastodon/features/account_edit/modals/name_modal.tsx b/app/javascript/mastodon/features/account_edit/modals/name_modal.tsx
index 07779a02a7..de42977140 100644
--- a/app/javascript/mastodon/features/account_edit/modals/name_modal.tsx
+++ b/app/javascript/mastodon/features/account_edit/modals/name_modal.tsx
@@ -33,12 +33,7 @@ export const NameModal: FC<BaseConfirmationModalProps> = ({ onClose }) => {
   );
   const maxLength = useAppSelector(
     (state) =>
-      state.server.getIn([
-        'server',
-        'configuration',
-        'accounts',
-        'max_display_name_length',
-      ]) as number | undefined,
+      state.server.server.item?.configuration.accounts.max_display_name_length,
   );
 
   const [newName, setNewName] = useState(displayName ?? '');
diff --git a/app/javascript/mastodon/features/account_timeline/modals/join_modal.tsx b/app/javascript/mastodon/features/account_timeline/modals/join_modal.tsx
index e5401fbebe..40e2b82bca 100644
--- a/app/javascript/mastodon/features/account_timeline/modals/join_modal.tsx
+++ b/app/javascript/mastodon/features/account_timeline/modals/join_modal.tsx
@@ -31,7 +31,7 @@ const selectServerName = createAppSelector(
   [
     (state) => state.accounts,
     (_, accountId: string) => accountId,
-    (state) => state.server.getIn(['server', 'domain']) as string | undefined,
+    (state) => state.server.server.item?.domain,
   ],
   (accounts, accountId, serverDomain) => {
     const acct = accounts.getIn([accountId, 'acct']) as string | undefined;
diff --git a/app/javascript/mastodon/features/interaction_modal/index.tsx b/app/javascript/mastodon/features/interaction_modal/index.tsx
index a4ba40c069..ef1d3e1111 100644
--- a/app/javascript/mastodon/features/interaction_modal/index.tsx
+++ b/app/javascript/mastodon/features/interaction_modal/index.tsx
@@ -419,9 +419,7 @@ const InteractionModal: React.FC<{
 }> = ({ accountId, url, intent }) => {
   const dispatch = useAppDispatch();
   const signupUrl = useAppSelector(
-    (state) =>
-      (state.server.getIn(['server', 'registrations', 'url'], null) ||
-        '/auth/sign_up') as string,
+    (state) => state.server.server.item?.registrations.url ?? '/auth/sign_up',
   );
   const account = useAppSelector((state) => state.accounts.get(accountId));
   const name = <DisplayName account={account} variant='simple' />;
diff --git a/app/javascript/mastodon/features/navigation_panel/components/sign_in_banner.tsx b/app/javascript/mastodon/features/navigation_panel/components/sign_in_banner.tsx
index ebcb532bb4..f9cf4cb28f 100644
--- a/app/javascript/mastodon/features/navigation_panel/components/sign_in_banner.tsx
+++ b/app/javascript/mastodon/features/navigation_panel/components/sign_in_banner.tsx
@@ -20,10 +20,7 @@ export const SignInBanner: React.FC = () => {
   let signupButton: React.ReactNode;
 
   const signupUrl = useAppSelector(
-    (state) =>
-      (state.server.getIn(['server', 'registrations', 'url'], null) as
-        | string
-        | null) ?? '/auth/sign_up',
+    (state) => state.server.server.item?.registrations.url ?? '/auth/sign_up',
   );
 
   if (sso_redirect) {
diff --git a/app/javascript/mastodon/features/ui/components/navigation_bar.tsx b/app/javascript/mastodon/features/ui/components/navigation_bar.tsx
index def1835c3e..ec45e395b2 100644
--- a/app/javascript/mastodon/features/ui/components/navigation_bar.tsx
+++ b/app/javascript/mastodon/features/ui/components/navigation_bar.tsx
@@ -84,10 +84,7 @@ const NotificationsButton = () => {
 const LoginOrSignUp: React.FC = () => {
   const dispatch = useAppDispatch();
   const signupUrl = useAppSelector(
-    (state) =>
-      (state.server.getIn(['server', 'registrations', 'url'], null) as
-        | string
-        | null) ?? '/auth/sign_up',
+    (state) => state.server.server.item?.registrations.url ?? '/auth/sign_up',
   );
 
   const openClosedRegistrationsModal = useCallback(() => {
@@ -95,7 +92,7 @@ const LoginOrSignUp: React.FC = () => {
   }, [dispatch]);
 
   useEffect(() => {
-    dispatch(fetchServer());
+    void dispatch(fetchServer());
   }, [dispatch]);
 
   if (sso_redirect) {
diff --git a/app/javascript/mastodon/features/ui/components/report_collection_modal.tsx b/app/javascript/mastodon/features/ui/components/report_collection_modal.tsx
index 945d6f0534..6e9492226d 100644
--- a/app/javascript/mastodon/features/ui/components/report_collection_modal.tsx
+++ b/app/javascript/mastodon/features/ui/components/report_collection_modal.tsx
@@ -52,7 +52,7 @@ export const ReportCollectionModal: React.FC<{
   const account = useAccount(account_id);
 
   useEffect(() => {
-    dispatch(fetchServer());
+    void dispatch(fetchServer());
   }, [dispatch]);
 
   const [submitState, setSubmitState] = useState<
diff --git a/app/javascript/mastodon/models/server.ts b/app/javascript/mastodon/models/server.ts
new file mode 100644
index 0000000000..0a01a56962
--- /dev/null
+++ b/app/javascript/mastodon/models/server.ts
@@ -0,0 +1,21 @@
+import type {
+  ApiInstanceJSON,
+  ApiExtendedDescriptionJSON,
+  ApiDomainBlockJSON,
+} from 'mastodon/api_types/instance';
+
+export type Server = ApiInstanceJSON;
+
+export const createServerFromServerJSON = (obj: ApiInstanceJSON): Server => obj;
+
+export type ExtendedDescription = ApiExtendedDescriptionJSON;
+
+export const createExtendedDescriptionFromServerJSON = (
+  obj: ApiExtendedDescriptionJSON,
+): ExtendedDescription => obj;
+
+export type DomainBlock = ApiDomainBlockJSON;
+
+export const createDomainBlockFromServerJSON = (
+  obj: ApiDomainBlockJSON,
+): DomainBlock => obj;
diff --git a/app/javascript/mastodon/reducers/index.ts b/app/javascript/mastodon/reducers/index.ts
index c3bc5792ac..2d2c8fbab5 100644
--- a/app/javascript/mastodon/reducers/index.ts
+++ b/app/javascript/mastodon/reducers/index.ts
@@ -30,7 +30,7 @@ import { pollsReducer } from './polls';
 import push_notifications from './push_notifications';
 import { relationshipsReducer } from './relationships';
 import { searchReducer } from './search';
-import server from './server';
+import { serverReducer } from './server';
 import settings from './settings';
 import { sliceReducers } from './slices';
 import status_lists from './status_lists';
@@ -58,7 +58,7 @@ const reducers = {
   relationships: relationshipsReducer,
   settings,
   push_notifications,
-  server,
+  server: serverReducer,
   contexts: contextsReducer,
   compose: composeReducer,
   search: searchReducer,
diff --git a/app/javascript/mastodon/reducers/server.js b/app/javascript/mastodon/reducers/server.js
deleted file mode 100644
index 2bbf0f9a30..0000000000
--- a/app/javascript/mastodon/reducers/server.js
+++ /dev/null
@@ -1,63 +0,0 @@
-import { Map as ImmutableMap, List as ImmutableList, fromJS } from 'immutable';
-
-import {
-  SERVER_FETCH_REQUEST,
-  SERVER_FETCH_SUCCESS,
-  SERVER_FETCH_FAIL,
-  SERVER_TRANSLATION_LANGUAGES_FETCH_REQUEST,
-  SERVER_TRANSLATION_LANGUAGES_FETCH_SUCCESS,
-  SERVER_TRANSLATION_LANGUAGES_FETCH_FAIL,
-  EXTENDED_DESCRIPTION_REQUEST,
-  EXTENDED_DESCRIPTION_SUCCESS,
-  EXTENDED_DESCRIPTION_FAIL,
-  SERVER_DOMAIN_BLOCKS_FETCH_REQUEST,
-  SERVER_DOMAIN_BLOCKS_FETCH_SUCCESS,
-  SERVER_DOMAIN_BLOCKS_FETCH_FAIL,
-} from 'mastodon/actions/server';
-
-const initialState = ImmutableMap({
-  server: ImmutableMap({
-    isLoading: false,
-  }),
-
-  extendedDescription: ImmutableMap({
-    isLoading: false,
-  }),
-
-  domainBlocks: ImmutableMap({
-    isLoading: false,
-    isAvailable: true,
-    items: ImmutableList(),
-  }),
-});
-
-export default function server(state = initialState, action) {
-  switch (action.type) {
-  case SERVER_FETCH_REQUEST:
-    return state.setIn(['server', 'isLoading'], true);
-  case SERVER_FETCH_SUCCESS:
-    return state.set('server', fromJS(action.server)).setIn(['server', 'isLoading'], false);
-  case SERVER_FETCH_FAIL:
-    return state.setIn(['server', 'isLoading'], false);
-  case SERVER_TRANSLATION_LANGUAGES_FETCH_REQUEST:
-    return state.setIn(['translationLanguages', 'isLoading'], true);
-  case SERVER_TRANSLATION_LANGUAGES_FETCH_SUCCESS:
-    return state.setIn(['translationLanguages', 'items'], fromJS(action.translationLanguages)).setIn(['translationLanguages', 'isLoading'], false);
-  case SERVER_TRANSLATION_LANGUAGES_FETCH_FAIL:
-    return state.setIn(['translationLanguages', 'isLoading'], false);
-  case EXTENDED_DESCRIPTION_REQUEST:
-    return state.setIn(['extendedDescription', 'isLoading'], true);
-  case EXTENDED_DESCRIPTION_SUCCESS:
-    return state.set('extendedDescription', fromJS(action.description)).setIn(['extendedDescription', 'isLoading'], false);
-  case EXTENDED_DESCRIPTION_FAIL:
-    return state.setIn(['extendedDescription', 'isLoading'], false);
-  case SERVER_DOMAIN_BLOCKS_FETCH_REQUEST:
-    return state.setIn(['domainBlocks', 'isLoading'], true);
-  case SERVER_DOMAIN_BLOCKS_FETCH_SUCCESS:
-    return state.setIn(['domainBlocks', 'items'], fromJS(action.blocks)).setIn(['domainBlocks', 'isLoading'], false).setIn(['domainBlocks', 'isAvailable'], action.isAvailable);
-  case SERVER_DOMAIN_BLOCKS_FETCH_FAIL:
-    return state.setIn(['domainBlocks', 'isLoading'], false);
-  default:
-    return state;
-  }
-}
diff --git a/app/javascript/mastodon/reducers/server.ts b/app/javascript/mastodon/reducers/server.ts
new file mode 100644
index 0000000000..92cec39af0
--- /dev/null
+++ b/app/javascript/mastodon/reducers/server.ts
@@ -0,0 +1,127 @@
+import { createReducer } from '@reduxjs/toolkit';
+
+import {
+  fetchServer,
+  fetchServerTranslationLanguages,
+  fetchExtendedDescription,
+  fetchDomainBlocks,
+} from 'mastodon/actions/server';
+import type {
+  Server,
+  ExtendedDescription,
+  DomainBlock,
+} from 'mastodon/models/server';
+import {
+  createServerFromServerJSON,
+  createExtendedDescriptionFromServerJSON,
+  createDomainBlockFromServerJSON,
+} from 'mastodon/models/server';
+
+interface State {
+  server: {
+    isLoading: boolean;
+    item?: Server;
+  };
+
+  extendedDescription: {
+    isLoading: boolean;
+    item?: ExtendedDescription;
+  };
+
+  translationLanguages: {
+    isLoading: boolean;
+    item?: Record<string, string[]>;
+  };
+
+  domainBlocks: {
+    isLoading: boolean;
+    isAvailable: boolean;
+    items: DomainBlock[];
+  };
+}
+
+const initialState: State = {
+  server: {
+    isLoading: false,
+    item: undefined,
+  },
+
+  extendedDescription: {
+    isLoading: false,
+    item: undefined,
+  },
+
+  translationLanguages: {
+    isLoading: false,
+    item: undefined,
+  },
+
+  domainBlocks: {
+    isLoading: false,
+    isAvailable: true,
+    items: [],
+  },
+};
+
+export const serverReducer = createReducer(initialState, (builder) => {
+  builder.addCase(fetchServer.pending, (state) => {
+    state.server.isLoading = true;
+  });
+
+  builder.addCase(fetchServer.fulfilled, (state, action) => {
+    state.server.item = createServerFromServerJSON(action.payload);
+    state.server.isLoading = false;
+  });
+
+  builder.addCase(fetchServer.rejected, (state) => {
+    state.server.isLoading = false;
+  });
+
+  builder.addCase(fetchExtendedDescription.pending, (state) => {
+    state.extendedDescription.isLoading = true;
+  });
+
+  builder.addCase(fetchExtendedDescription.fulfilled, (state, action) => {
+    state.extendedDescription.item = createExtendedDescriptionFromServerJSON(
+      action.payload,
+    );
+    state.extendedDescription.isLoading = false;
+  });
+
+  builder.addCase(fetchExtendedDescription.rejected, (state) => {
+    state.extendedDescription.isLoading = false;
+  });
+
+  builder.addCase(fetchServerTranslationLanguages.pending, (state) => {
+    state.translationLanguages.isLoading = true;
+  });
+
+  builder.addCase(
+    fetchServerTranslationLanguages.fulfilled,
+    (state, action) => {
+      state.translationLanguages.item = action.payload;
+      state.translationLanguages.isLoading = false;
+    },
+  );
+
+  builder.addCase(fetchServerTranslationLanguages.rejected, (state) => {
+    state.translationLanguages.isLoading = false;
+  });
+
+  builder.addCase(fetchDomainBlocks.pending, (state) => {
+    state.domainBlocks.isLoading = true;
+  });
+
+  builder.addCase(fetchDomainBlocks.fulfilled, (state, action) => {
+    state.domainBlocks.items = action.payload.map((obj) =>
+      createDomainBlockFromServerJSON(obj),
+    );
+    state.domainBlocks.isLoading = false;
+    state.domainBlocks.isAvailable = true;
+  });
+
+  builder.addCase(fetchDomainBlocks.rejected, (state) => {
+    state.domainBlocks.isLoading = false;
+    state.domainBlocks.isAvailable = false;
+  });
+});
diff --git a/app/javascript/mastodon/reducers/slices/profile_edit.ts b/app/javascript/mastodon/reducers/slices/profile_edit.ts
index 2437352fbd..bc463ac1bd 100644
--- a/app/javascript/mastodon/reducers/slices/profile_edit.ts
+++ b/app/javascript/mastodon/reducers/slices/profile_edit.ts
@@ -282,12 +282,8 @@ export const updateField = createAppAsyncThunk(
       throw new Error('Profile fields not found');
     }
 
-    const maxFields = getState().server.getIn([
-      'server',
-      'configuration',
-      'accounts',
-      'max_fields',
-    ]) as number | undefined;
+    const maxFields =
+      getState().server.server.item?.configuration.accounts.max_profile_fields;
     if (maxFields && fields.length >= maxFields && !arg.id) {
       throw new Error('Maximum number of profile fields reached');
     }