diff --git a/ghost/admin-x-settings/src/admin-x-ds/global/PreviewModal.tsx b/ghost/admin-x-settings/src/admin-x-ds/global/PreviewModal.tsx
index 266b10d7c9..e6f336b1ca 100644
--- a/ghost/admin-x-settings/src/admin-x-ds/global/PreviewModal.tsx
+++ b/ghost/admin-x-settings/src/admin-x-ds/global/PreviewModal.tsx
@@ -14,12 +14,13 @@ export interface PreviewModalProps {
     okColor?: string;
     onCancel?: () => void;
     onOk?: () => void;
+    buttonsDisabled?: boolean
     customButtons?: React.ReactNode;
     customHeader?: React.ReactNode;
     sidebarPadding?: boolean;
 }
 
-const PreviewModal: React.FC<PreviewModalProps> = ({
+export const PreviewModalContent: React.FC<PreviewModalProps> = ({
     title,
     sidebar,
     preview,
@@ -28,6 +29,7 @@ const PreviewModal: React.FC<PreviewModalProps> = ({
     okColor = 'black',
     onCancel,
     onOk,
+    buttonsDisabled,
     customButtons,
     customHeader,
     sidebarPadding = true
@@ -41,7 +43,8 @@ const PreviewModal: React.FC<PreviewModalProps> = ({
             label: cancelLabel,
             onClick: (onCancel ? onCancel : () => {
                 modal.remove();
-            })
+            }),
+            disabled: buttonsDisabled
         });
 
         buttons.push({
@@ -49,7 +52,8 @@ const PreviewModal: React.FC<PreviewModalProps> = ({
             label: okLabel,
             color: okColor,
             className: 'min-w-[80px]',
-            onClick: onOk
+            onClick: onOk,
+            disabled: buttonsDisabled
         });
     }
 
@@ -82,4 +86,4 @@ const PreviewModal: React.FC<PreviewModalProps> = ({
     );
 };
 
-export default NiceModal.create(PreviewModal);
\ No newline at end of file
+export default NiceModal.create(PreviewModalContent);
diff --git a/ghost/admin-x-settings/src/admin-x-ds/global/TextField.tsx b/ghost/admin-x-settings/src/admin-x-ds/global/TextField.tsx
index b6809f9717..0f2c3884b9 100644
--- a/ghost/admin-x-settings/src/admin-x-ds/global/TextField.tsx
+++ b/ghost/admin-x-settings/src/admin-x-ds/global/TextField.tsx
@@ -3,13 +3,11 @@ import Hint from './Hint';
 import React, {useId} from 'react';
 import clsx from 'clsx';
 
-type TextFieldType = 'text' | 'number' | 'email' | 'password' | 'file' | 'date' | 'time' | 'search';
-
 interface TextFieldProps {
     inputRef?: React.RefObject<HTMLInputElement>;
     title?: string;
     hideTitle?: boolean;
-    type?: TextFieldType;
+    type?: React.InputHTMLAttributes<HTMLInputElement>['type'];
     value?: string;
     error?: boolean;
     placeholder?: string;
diff --git a/ghost/admin-x-settings/src/components/providers/ServiceProvider.tsx b/ghost/admin-x-settings/src/components/providers/ServiceProvider.tsx
index f53a8d9815..954ee1d2f2 100644
--- a/ghost/admin-x-settings/src/components/providers/ServiceProvider.tsx
+++ b/ghost/admin-x-settings/src/components/providers/ServiceProvider.tsx
@@ -1,6 +1,5 @@
-import React from 'react';
+import React, {createContext} from 'react';
 import setupGhostApi from '../../utils/api';
-import {createContext} from 'react';
 
 export interface FileService {
     uploadImage: (file: File) => Promise<string>;
@@ -21,6 +20,7 @@ const ServicesContext = createContext<ServicesContextProps>({
 });
 
 const ServicesProvider: React.FC<ServicesProviderProps> = ({children, ghostVersion}) => {
+    // TODO: Will this re-render? (if so, will it make duplicate requests because the api object is different?)
     const apiService = setupGhostApi({ghostVersion});
     const fileService = {
         uploadImage: async (file: File): Promise<string> => {
@@ -38,4 +38,4 @@ const ServicesProvider: React.FC<ServicesProviderProps> = ({children, ghostVersi
     );
 };
 
-export {ServicesContext, ServicesProvider};
\ No newline at end of file
+export {ServicesContext, ServicesProvider};
diff --git a/ghost/admin-x-settings/src/components/settings/site/DesignModal.tsx b/ghost/admin-x-settings/src/components/settings/site/DesignModal.tsx
index b0818dcdd5..e1ca042afc 100644
--- a/ghost/admin-x-settings/src/components/settings/site/DesignModal.tsx
+++ b/ghost/admin-x-settings/src/components/settings/site/DesignModal.tsx
@@ -1,37 +1,33 @@
-import BrandSettings from './designAndBranding/BrandSettings';
-import Button from '../../../admin-x-ds/global/Button';
-import NiceModal from '@ebay/nice-modal-react';
-import PreviewModal from '../../../admin-x-ds/global/PreviewModal';
-import React from 'react';
-import SettingGroup from '../../../admin-x-ds/settings/SettingGroup';
+import BrandSettings, {BrandSettingValues} from './designAndBranding/BrandSettings';
+import ConfirmationModal from '../../../admin-x-ds/global/ConfirmationModal';
+import NiceModal, {useModal} from '@ebay/nice-modal-react';
+import React, {useContext, useEffect, useState} from 'react';
 import StickyFooter from '../../../admin-x-ds/global/StickyFooter';
-import TabView from '../../../admin-x-ds/global/TabView';
+import TabView, {Tab} from '../../../admin-x-ds/global/TabView';
 import ThemePreview from './designAndBranding/ThemePreivew';
 import ThemeSettings from './designAndBranding/ThemeSettings';
-import {Tab} from '../../../admin-x-ds/global/TabView';
+import useSettingGroup from '../../../hooks/useSettingGroup';
+import {CustomThemeSetting, SettingValue} from '../../../types/api';
+import {PreviewModalContent} from '../../../admin-x-ds/global/PreviewModal';
+import {ServicesContext} from '../../providers/ServiceProvider';
 
-const Sidebar: React.FC = () => {
+const Sidebar: React.FC<{
+    brandSettings: BrandSettingValues
+    updateBrandSetting: (key: string, value: SettingValue) => void
+    themeSettingSections: Array<{id: string, title: string, settings: CustomThemeSetting[]}>
+    updateThemeSetting: (updated: CustomThemeSetting) => void
+}> = ({brandSettings,updateBrandSetting,themeSettingSections,updateThemeSetting}) => {
     const tabs: Tab[] = [
         {
             id: 'brand',
             title: 'Brand',
-            contents: <BrandSettings />
+            contents: <BrandSettings updateSetting={updateBrandSetting} values={brandSettings} />
         },
-        {
-            id: 'site-wide',
-            title: 'Site wide',
-            contents: <ThemeSettings settingSection='site-wide' />
-        },
-        {
-            id: 'homepage',
-            title: 'Homepage',
-            contents: <ThemeSettings settingSection='homepage' />
-        },
-        {
-            id: 'post',
-            title: 'Post',
-            contents: <ThemeSettings settingSection='post' />
-        }
+        ...themeSettingSections.map(({id, title, settings}) => ({
+            id,
+            title,
+            contents: <ThemeSettings settings={settings} updateSetting={updateThemeSetting} />
+        }))
     ];
 
     return (
@@ -50,24 +46,93 @@ const Sidebar: React.FC = () => {
 };
 
 const DesignModal: React.FC = () => {
-    const openPreviewModal = () => {
-        NiceModal.show(PreviewModal, {
-            title: 'Design',
-            okLabel: 'Save',
-            preview: <ThemePreview />,
-            sidebar: <Sidebar />,
-            sidebarPadding: false
+    const modal = useModal();
+
+    const {api} = useContext(ServicesContext);
+    const [themeSettings, setThemeSettings] = useState<Array<CustomThemeSetting & { dirty?: boolean }>>([]);
+
+    useEffect(() => {
+        api.customThemeSettings.browse().then((response) => {
+            setThemeSettings(response.custom_theme_settings);
         });
+    }, [api]);
+
+    const {
+        saveState,
+        handleSave,
+        updateSetting,
+        getSettingValues,
+        dirty
+    } = useSettingGroup({
+        onSave: async () => {
+            if (themeSettings.some(setting => setting.dirty)) {
+                const response = await api.customThemeSettings.edit(themeSettings);
+                setThemeSettings(response.custom_theme_settings);
+            }
+        }
+    });
+    const [description, accentColor, icon, logo, coverImage] = getSettingValues(['description', 'accent_color', 'icon', 'logo', 'cover_image']) as string[];
+
+    const themeSettingGroups = themeSettings.reduce((groups, setting) => {
+        const group = (setting.group === 'homepage' || setting.group === 'post') ? setting.group : 'site-wide';
+
+        return {
+            ...groups,
+            [group]: (groups[group] || []).concat(setting)
+        };
+    }, {} as {[key: string]: CustomThemeSetting[] | undefined});
+
+    const themeSettingSections = Object.entries(themeSettingGroups).map(([id, settings]) => ({
+        id,
+        settings: settings || [],
+        title: id === 'site-wide' ? 'Site wide' : (id === 'homepage' ? 'Homepage' : 'Post')
+    }));
+
+    const updateThemeSetting = (updated: CustomThemeSetting) => {
+        setThemeSettings(themeSettings.map(setting => (
+            setting.key === updated.key ? {...updated, dirty: true} : setting
+        )));
     };
 
-    return (
-        <SettingGroup
-            customButtons={<Button color='green' label='Customize' link onClick={openPreviewModal}/>}
-            description="Customize your site and manage themes"
-            navid='branding-and-design'
-            title="Branding and design"
-        />
-    );
+    return <PreviewModalContent
+        buttonsDisabled={saveState === 'saving'}
+        okLabel='Save'
+        preview={<ThemePreview />}
+        sidebar={<Sidebar
+            brandSettings={{description, accentColor, icon, logo, coverImage}}
+            themeSettingSections={themeSettingSections}
+            updateBrandSetting={updateSetting}
+            updateThemeSetting={updateThemeSetting}
+        />}
+        sidebarPadding={false}
+        title='Design'
+        onCancel={() => {
+            if (dirty || themeSettings.some(setting => setting.dirty)) {
+                NiceModal.show(ConfirmationModal, {
+                    title: 'Are you sure you want to leave this page?',
+                    prompt: (
+                        <>
+                            <p>Hey there! It looks like you didn&lsquo;t save the changes you made.</p>
+                            <p>Save before you go!</p>
+                        </>
+                    ),
+                    okLabel: 'Leave',
+                    okColor: 'red',
+                    onOk: (confirmModal) => {
+                        confirmModal?.remove();
+                        modal.remove();
+                    },
+                    cancelLabel: 'Stay'
+                });
+            } else {
+                modal.remove();
+            }
+        }}
+        onOk={async () => {
+            await handleSave();
+            modal.remove();
+        }}
+    />;
 };
 
-export default DesignModal;
\ No newline at end of file
+export default NiceModal.create(DesignModal);
diff --git a/ghost/admin-x-settings/src/components/settings/site/DesignSetting.tsx b/ghost/admin-x-settings/src/components/settings/site/DesignSetting.tsx
new file mode 100644
index 0000000000..4e13bbddb6
--- /dev/null
+++ b/ghost/admin-x-settings/src/components/settings/site/DesignSetting.tsx
@@ -0,0 +1,22 @@
+import Button from '../../../admin-x-ds/global/Button';
+import DesignModal from './DesignModal';
+import NiceModal from '@ebay/nice-modal-react';
+import React from 'react';
+import SettingGroup from '../../../admin-x-ds/settings/SettingGroup';
+
+const DesignSetting: React.FC = () => {
+    const openPreviewModal = () => {
+        NiceModal.show(DesignModal);
+    };
+
+    return (
+        <SettingGroup
+            customButtons={<Button color='green' label='Customize' link onClick={openPreviewModal}/>}
+            description="Customize your site and manage themes"
+            navid='branding-and-design'
+            title="Branding and design"
+        />
+    );
+};
+
+export default DesignSetting;
diff --git a/ghost/admin-x-settings/src/components/settings/site/SiteSettings.tsx b/ghost/admin-x-settings/src/components/settings/site/SiteSettings.tsx
index 750cae2f8b..f45146b3d4 100644
--- a/ghost/admin-x-settings/src/components/settings/site/SiteSettings.tsx
+++ b/ghost/admin-x-settings/src/components/settings/site/SiteSettings.tsx
@@ -1,4 +1,4 @@
-import DesignModal from './DesignModal';
+import DesignSetting from './DesignSetting';
 import React from 'react';
 import SettingSection from '../../../admin-x-ds/settings/SettingSection';
 
@@ -6,10 +6,10 @@ const SiteSettings: React.FC = () => {
     return (
         <>
             <SettingSection title="Site">
-                <DesignModal />
+                <DesignSetting />
             </SettingSection>
         </>
     );
 };
 
-export default SiteSettings;
\ No newline at end of file
+export default SiteSettings;
diff --git a/ghost/admin-x-settings/src/components/settings/site/designAndBranding/BrandSettings.tsx b/ghost/admin-x-settings/src/components/settings/site/designAndBranding/BrandSettings.tsx
index a098bb74aa..2ff4ee4b57 100644
--- a/ghost/admin-x-settings/src/components/settings/site/designAndBranding/BrandSettings.tsx
+++ b/ghost/admin-x-settings/src/components/settings/site/designAndBranding/BrandSettings.tsx
@@ -1,17 +1,22 @@
 import Heading from '../../../../admin-x-ds/global/Heading';
 import Hint from '../../../../admin-x-ds/global/Hint';
 import ImageUpload from '../../../../admin-x-ds/global/ImageUpload';
-import React from 'react';
+import React, {useContext} from 'react';
 import SettingGroupContent from '../../../../admin-x-ds/settings/SettingGroupContent';
 import TextField from '../../../../admin-x-ds/global/TextField';
-import useSettingGroup from '../../../../hooks/useSettingGroup';
+import {ServicesContext} from '../../../providers/ServiceProvider';
+import {SettingValue} from '../../../../types/api';
 
-const BrandSettings: React.FC = () => {
-    const {
-        getSettingValues
-    } = useSettingGroup();
+export interface BrandSettingValues {
+    description: string
+    accentColor: string
+    icon: string | null
+    logo: string | null
+    coverImage: string | null
+}
 
-    const [description, accentColor] = getSettingValues(['description', 'accent_color']) as string[];
+const BrandSettings: React.FC<{ values: BrandSettingValues, updateSetting: (key: string, value: SettingValue) => void }> = ({values,updateSetting}) => {
+    const {fileService} = useContext(ServicesContext);
 
     return (
         <div className='mt-7'>
@@ -21,7 +26,8 @@ const BrandSettings: React.FC = () => {
                     clearBg={true}
                     hint='Used in your theme, meta data and search results'
                     title='Site description'
-                    value={description}
+                    value={values.description}
+                    onChange={event => updateSetting('description', event.target.value)}
                 />
                 <div className='flex items-center justify-between gap-3'>
                     <Heading level={6}>Accent color</Heading>
@@ -32,7 +38,9 @@ const BrandSettings: React.FC = () => {
                             className='text-right'
                             clearBg={true}
                             maxLength={7}
-                            value={accentColor}
+                            type='color'
+                            value={values.accentColor}
+                            onChange={event => updateSetting('accent_color', event.target.value)}
                         />
                     </div>
                 </div>
@@ -44,8 +52,10 @@ const BrandSettings: React.FC = () => {
                             height='36px'
                             id='logo'
                             width='150px'
-                            onDelete={() => {}}
-                            onUpload={() => {}}
+                            onDelete={() => updateSetting('icon', null)}
+                            onUpload={async (file) => {
+                                updateSetting('icon', await fileService!.uploadImage(file));
+                            }}
                         >
                         Upload icon
                         </ImageUpload>
@@ -56,8 +66,10 @@ const BrandSettings: React.FC = () => {
                     <ImageUpload
                         height='80px'
                         id='logo'
-                        onDelete={() => {}}
-                        onUpload={() => {}}
+                        onDelete={() => updateSetting('logo', null)}
+                        onUpload={async (file) => {
+                            updateSetting('logo', await fileService!.uploadImage(file));
+                        }}
                     >
                     Upload logo
                     </ImageUpload>
@@ -67,8 +79,10 @@ const BrandSettings: React.FC = () => {
                     <ImageUpload
                         height='140px'
                         id='cover'
-                        onDelete={() => {}}
-                        onUpload={() => {}}
+                        onDelete={() => updateSetting('cover_image', null)}
+                        onUpload={async (file) => {
+                            updateSetting('cover_image', await fileService!.uploadImage(file));
+                        }}
                     >
                     Upload cover
                     </ImageUpload>
@@ -78,4 +92,4 @@ const BrandSettings: React.FC = () => {
     );
 };
 
-export default BrandSettings;
\ No newline at end of file
+export default BrandSettings;
diff --git a/ghost/admin-x-settings/src/components/settings/site/designAndBranding/ThemeSettings.tsx b/ghost/admin-x-settings/src/components/settings/site/designAndBranding/ThemeSettings.tsx
index 6447c38ab7..60cc3cc063 100644
--- a/ghost/admin-x-settings/src/components/settings/site/designAndBranding/ThemeSettings.tsx
+++ b/ghost/admin-x-settings/src/components/settings/site/designAndBranding/ThemeSettings.tsx
@@ -1,17 +1,81 @@
-import React from 'react';
+import Heading from '../../../../admin-x-ds/global/Heading';
+import ImageUpload from '../../../../admin-x-ds/global/ImageUpload';
+import React, {useContext} from 'react';
+import Select from '../../../../admin-x-ds/global/Select';
+import SettingGroupContent from '../../../../admin-x-ds/settings/SettingGroupContent';
+import TextField from '../../../../admin-x-ds/global/TextField';
+import Toggle from '../../../../admin-x-ds/global/Toggle';
+import {CustomThemeSetting} from '../../../../types/api';
+import {ServicesContext} from '../../../providers/ServiceProvider';
+import {humanizeSettingKey} from '../../../../utils/helpers';
 
-type ThemeSettingSection = 'site-wide' | 'homepage' | 'post';
+const ThemeSetting: React.FC<{
+    setting: CustomThemeSetting,
+    setSetting: <Setting extends CustomThemeSetting>(value: Setting['value']) => void
+}> = ({setting, setSetting}) => {
+    const {fileService} = useContext(ServicesContext);
 
-interface ThemeSettingsProps {
-    settingSection: ThemeSettingSection;
-}
+    const handleImageUpload = async (file: File) => {
+        const imageUrl = await fileService!.uploadImage(file);
+        setSetting(imageUrl);
+    };
 
-const ThemeSettings: React.FC<ThemeSettingsProps> = ({settingSection}) => {
+    switch (setting.type) {
+    case 'text':
+        return (
+            <TextField
+                title={humanizeSettingKey(setting.key)}
+                value={setting.value || ''}
+                onChange={event => setSetting(event.target.value)}
+            />
+        );
+    case 'boolean':
+        return (
+            <Toggle
+                direction="rtl"
+                id={`theme-setting-${setting.key}`}
+                label={humanizeSettingKey(setting.key)}
+                onChange={event => setSetting(event.target.checked)}
+            />
+        );
+    case 'select':
+        return (
+            <Select
+                defaultSelectedOption={setting.value}
+                options={setting.options.map(option => ({label: option, value: option}))}
+                title={humanizeSettingKey(setting.key)}
+                onSelect={value => setSetting(value)}
+            />
+        );
+    case 'color':
+        return (
+            <TextField
+                title={humanizeSettingKey(setting.key)}
+                type='color'
+                value={setting.value || ''}
+                onChange={event => setSetting(event.target.value)}
+            />
+        );
+    case 'image':
+        return <>
+            <Heading useLabelTag>{humanizeSettingKey(setting.key)}</Heading>
+            <ImageUpload
+                height={setting.value ? '100px' : '32px'}
+                id='cover-image'
+                imageURL={setting.value || ''}
+                onDelete={() => setSetting(null)}
+                onUpload={file => handleImageUpload(file)}
+            >Upload image</ImageUpload>
+        </>;
+    }
+};
+
+const ThemeSettings: React.FC<{ settings: CustomThemeSetting[], updateSetting: (setting: CustomThemeSetting) => void }> = ({settings, updateSetting}) => {
     return (
-        <>
-            {settingSection}
-        </>
+        <SettingGroupContent className='mt-7'>
+            {settings.map(setting => <ThemeSetting key={setting.key} setSetting={(value: any) => updateSetting({...setting, value})} setting={setting} />)}
+        </SettingGroupContent>
     );
 };
 
-export default ThemeSettings;
\ No newline at end of file
+export default ThemeSettings;
diff --git a/ghost/admin-x-settings/src/hooks/useSettingGroup.tsx b/ghost/admin-x-settings/src/hooks/useSettingGroup.tsx
index 574db59dc5..b18f69b14a 100644
--- a/ghost/admin-x-settings/src/hooks/useSettingGroup.tsx
+++ b/ghost/admin-x-settings/src/hooks/useSettingGroup.tsx
@@ -12,11 +12,12 @@ export interface SettingGroupHook {
     saveState: SaveState;
     siteData: SiteData | null;
     focusRef: React.RefObject<HTMLInputElement>;
-    handleSave: () => void;
+    handleSave: () => Promise<void>;
     handleCancel: () => void;
     updateSetting: (key: string, value: SettingValue) => void;
     getSettingValues: (keys: string[]) => (SettingValue|undefined)[];
     handleStateChange: (newState: TSettingGroupStates) => void;
+    dirty: boolean
 }
 
 type UpdateAction = {
@@ -54,7 +55,7 @@ function settingsReducer(state: Setting[], action: ActionType) {
     }
 }
 
-const useSettingGroup = (): SettingGroupHook => {
+const useSettingGroup = ({onSave}: { onSave?: () => void | Promise<void> } = {}): SettingGroupHook => {
     // create a ref to focus the input field
     const focusRef = useRef<HTMLInputElement>(null);
 
@@ -96,20 +97,29 @@ const useSettingGroup = (): SettingGroupHook => {
     // eslint-disable-next-line react-hooks/exhaustive-deps
     }, [settings]);
 
-    // function to save the changed settings via API
-    const handleSave = async () => {
-        const changedSettings = localSettings?.filter(setting => setting.dirty)
+    const changedSettings = () => {
+        return localSettings?.filter(setting => setting.dirty)
             ?.map((setting) => {
                 return {
                     key: setting.key,
                     value: setting.value
                 };
             });
-        if (!changedSettings?.length) {
+    };
+
+    // function to save the changed settings via API
+    const handleSave = async () => {
+        if (!changedSettings()?.length && !onSave) {
             return;
         }
+
         setSaveState('saving');
-        await saveSettings?.(changedSettings);
+        if (changedSettings()?.length) {
+            await saveSettings?.(changedSettings());
+        }
+        if (onSave) {
+            await onSave();
+        }
         setSaveState('saved');
         setCurrentState('view');
     };
@@ -156,7 +166,11 @@ const useSettingGroup = (): SettingGroupHook => {
         handleCancel,
         updateSetting,
         getSettingValues,
-        handleStateChange
+        handleStateChange,
+
+        get dirty() {
+            return !!changedSettings()?.length;
+        }
     };
 };
 
diff --git a/ghost/admin-x-settings/src/types/api.ts b/ghost/admin-x-settings/src/types/api.ts
index 620ba53305..f3ab413b2c 100644
--- a/ghost/admin-x-settings/src/types/api.ts
+++ b/ghost/admin-x-settings/src/types/api.ts
@@ -54,4 +54,23 @@ export type SiteData = {
     url: string;
     locale: string;
     version: string;
-};
\ No newline at end of file
+};
+
+type CustomThemeSettingData =
+    { type: 'text', value: string | null, default: string | null } |
+    { type: 'color', value: string, default: string } |
+    { type: 'image', value: string | null } |
+    { type: 'boolean', value: boolean, default: boolean } |
+    {
+        type: 'select',
+        value: string
+        default: string
+        options: string[]
+    };
+
+export type CustomThemeSetting = CustomThemeSettingData & {
+    id: string
+    key: string
+    // homepage and post are the only two groups we handle, but technically theme authors can put other things in package.json
+    group?: 'homepage' | 'post' | string
+}
diff --git a/ghost/admin-x-settings/src/utils/api.ts b/ghost/admin-x-settings/src/utils/api.ts
index bf8efb99c8..1e70b17c1f 100644
--- a/ghost/admin-x-settings/src/utils/api.ts
+++ b/ghost/admin-x-settings/src/utils/api.ts
@@ -1,4 +1,4 @@
-import {Setting, SiteData, User, UserRole} from '../types/api';
+import {CustomThemeSetting, Setting, SiteData, User, UserRole} from '../types/api';
 import {getGhostPaths} from './helpers';
 
 interface Meta {
@@ -49,6 +49,10 @@ export interface InvitesResponseType {
     invites: UserInvite[];
 }
 
+export interface CustomThemeSettingsResponseType {
+    custom_theme_settings: CustomThemeSetting[];
+}
+
 export interface SiteResponseType {
     site: SiteData;
 }
@@ -119,6 +123,10 @@ interface API {
             token?: string;
         }) => Promise<InvitesResponseType>;
         delete: (inviteId: string) => Promise<void>;
+    };
+    customThemeSettings: {
+        browse: () => Promise<CustomThemeSettingsResponseType>
+        edit: (newSettings: CustomThemeSetting[]) => Promise<CustomThemeSettingsResponseType>
     }
 }
 
@@ -129,7 +137,7 @@ interface GhostApiOptions {
 function setupGhostApi({ghostVersion}: GhostApiOptions): API {
     const {apiRoot} = getGhostPaths();
 
-    function fetcher(url: string, options: RequestOptions) {
+    function fetcher(url: string, options: RequestOptions = {}) {
         const endpoint = `${apiRoot}${url}`;
         // By default, we set the Content-Type header to application/json
         const defaultHeaders = {
@@ -300,6 +308,23 @@ function setupGhostApi({ghostVersion}: GhostApiOptions): API {
                 });
                 return;
             }
+        },
+        customThemeSettings: {
+            browse: async () => {
+                const response = await fetcher('/custom_theme_settings/');
+
+                const data: CustomThemeSettingsResponseType = await response.json();
+                return data;
+            },
+            edit: async (newSettings) => {
+                const response = await fetcher('/custom_theme_settings/', {
+                    method: 'PUT',
+                    body: JSON.stringify({custom_theme_settings: newSettings})
+                });
+
+                const data: CustomThemeSettingsResponseType = await response.json();
+                return data;
+            }
         }
     };
 
diff --git a/ghost/admin-x-settings/src/utils/helpers.ts b/ghost/admin-x-settings/src/utils/helpers.ts
index c80627675c..56730a1a3c 100644
--- a/ghost/admin-x-settings/src/utils/helpers.ts
+++ b/ghost/admin-x-settings/src/utils/helpers.ts
@@ -59,6 +59,15 @@ export function generateAvatarColor(name: string) {
     return 'hsl(' + h + ', ' + s + '%, ' + l + '%)';
 }
 
+export function humanizeSettingKey(key: string) {
+    const allCaps = ['API', 'CTA', 'RSS'];
+
+    return key
+        .replace(/^[a-z]/, char => char.toUpperCase())
+        .replace(/_/g, ' ')
+        .replace(new RegExp(`\\b(${allCaps.join('|')})\\b`, 'ig'), match => match.toUpperCase());
+}
+
 export function isOwnerUser(user: User) {
     return user.roles.some(role => role.name === 'Owner');
 }