diff --git a/package-lock.json b/package-lock.json
index da88342..e13e0a3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1505,6 +1505,16 @@
         "@types/react": "*"
       }
     },
+    "@types/react-bootstrap-typeahead": {
+      "version": "3.4.0",
+      "resolved": "https://registry.npmjs.org/@types/react-bootstrap-typeahead/-/react-bootstrap-typeahead-3.4.0.tgz",
+      "integrity": "sha512-J2JFcXWoY4234vnBGGh41PdTLMLQT9tZzkn1iBzuf/lRJv+tnGX2BtmbFUmKhwFzGFbjHqKubUvtHnFsYNohRQ==",
+      "dev": true,
+      "requires": {
+        "@types/react": "*",
+        "csstype": "^2.2.0"
+      }
+    },
     "@types/react-dom": {
       "version": "16.0.11",
       "resolved": "https://registry.npmjs.org/@types/react-dom/-/react-dom-16.0.11.tgz",
diff --git a/package.json b/package.json
index af45a0b..e8e5d45 100644
--- a/package.json
+++ b/package.json
@@ -14,6 +14,7 @@
     "@types/node": "^10.12.18",
     "@types/react": "^16.7.20",
     "@types/react-bootstrap-daterangepicker": "0.0.26",
+    "@types/react-bootstrap-typeahead": "^3.4.0",
     "@types/react-dom": "^16.0.11",
     "@types/react-router-dom": "^4.3.1",
     "@types/react-table": "^6.7.21",
diff --git a/src/components/settings/ConditionalForwardingSettings.js b/src/components/settings/ConditionalForwardingSettings.tsx
similarity index 79%
rename from src/components/settings/ConditionalForwardingSettings.js
rename to src/components/settings/ConditionalForwardingSettings.tsx
index 326cbaf..0361e06 100644
--- a/src/components/settings/ConditionalForwardingSettings.js
+++ b/src/components/settings/ConditionalForwardingSettings.tsx
@@ -9,8 +9,22 @@
  * Please see LICENSE file for your rights under this license. */
 
 import React, { Fragment } from "react";
-import PropTypes from "prop-types";
 import { Col, FormGroup, Input, Label } from "reactstrap";
+import i18next from "i18next";
+
+export interface ConditionalForwardingObject {
+  enabled: boolean,
+  routerIp: string,
+  domain: string
+}
+
+export interface ConditionalForwardingSettingsProps {
+  settings: ConditionalForwardingObject,
+  onUpdate: (settings: ConditionalForwardingObject) => void,
+  isRouterIpValid: boolean;
+  isDomainValid: boolean;
+  t: i18next.TranslationFunction
+}
 
 const ConditionalForwardingSettings = ({
   settings,
@@ -18,7 +32,7 @@ const ConditionalForwardingSettings = ({
   isRouterIpValid,
   isDomainValid,
   t
-}) => (
+}: ConditionalForwardingSettingsProps) => (
   <Fragment>
     <FormGroup check>
       <Label check>
@@ -61,12 +75,4 @@ const ConditionalForwardingSettings = ({
   </Fragment>
 );
 
-ConditionalForwardingSettings.propTypes = {
-  settings: PropTypes.object.isRequired,
-  onUpdate: PropTypes.func.isRequired,
-  isRouterIpValid: PropTypes.bool.isRequired,
-  isDomainValid: PropTypes.bool.isRequired,
-  t: PropTypes.func.isRequired
-};
-
 export default ConditionalForwardingSettings;
diff --git a/src/components/settings/DHCPInfo.js b/src/components/settings/DHCPInfo.tsx
similarity index 80%
rename from src/components/settings/DHCPInfo.js
rename to src/components/settings/DHCPInfo.tsx
index 4e15ae7..922b120 100644
--- a/src/components/settings/DHCPInfo.js
+++ b/src/components/settings/DHCPInfo.tsx
@@ -8,31 +8,26 @@
  * This file is copyright under the latest version of the EUPL.
  * Please see LICENSE file for your rights under this license. */
 
-import React, { Component } from "react";
-import { withNamespaces } from "react-i18next";
-import { ignoreCancel, makeCancelable } from "../../util";
-import api from "../../util/api";
-import {
-  Button,
-  Col,
-  Form,
-  FormGroup,
-  Input,
-  InputGroup,
-  InputGroupAddon,
-  Label
-} from "reactstrap";
-import {
-  isPositiveNumber,
-  isValidHostname,
-  isValidIpv4
-} from "../../util/validate";
-import Alert from "../common/Alert";
+import React, { ChangeEvent, Component, FormEvent } from "react";
+import { WithNamespaces, withNamespaces } from "react-i18next";
+import { CancelablePromise, ignoreCancel, makeCancelable } from "../../util";
+import api, { ApiDhcpSettings, ApiResultResponse } from "../../util/api";
+import { Button, Col, Form, FormGroup, Input, InputGroup, InputGroupAddon, Label } from "reactstrap";
+import { isValidHostname, isValidIpv4 } from "../../util/validate";
+import Alert, { AlertType } from "../common/Alert";
 
-class DHCPInfo extends Component {
-  state = {
+export interface DHCPInfoState {
+  alertMessage: string;
+  alertType: AlertType;
+  showAlert: boolean;
+  processing: boolean;
+  settings: ApiDhcpSettings;
+}
+
+class DHCPInfo extends Component<WithNamespaces, DHCPInfoState> {
+  state: DHCPInfoState = {
     alertMessage: "",
-    alertType: "",
+    alertType: "info",
     showAlert: false,
     processing: false,
     settings: {
@@ -40,27 +35,20 @@ class DHCPInfo extends Component {
       ip_start: "",
       ip_end: "",
       router_ip: "",
-      lease_time: "",
+      lease_time: 0,
       domain: "",
       ipv6_support: false
     }
   };
 
+  private loadHandler: undefined | CancelablePromise<ApiDhcpSettings>;
+  private updateHandler: undefined | CancelablePromise<ApiResultResponse>;
+
   loadDHCPInfo = () => {
     this.loadHandler = makeCancelable(api.getDHCPInfo());
     this.loadHandler.promise
       .then(res => {
-        this.setState({
-          settings: {
-            active: res.active,
-            ip_start: res.ip_start,
-            ip_end: res.ip_end,
-            router_ip: res.router_ip,
-            lease_time: res.lease_time,
-            domain: res.domain,
-            ipv6_support: res.ipv6_support
-          }
-        });
+        this.setState({ settings: res });
       })
       .catch(ignoreCancel);
   };
@@ -70,7 +58,9 @@ class DHCPInfo extends Component {
   }
 
   componentWillUnmount() {
-    this.loadHandler.cancel();
+    if (this.loadHandler) {
+      this.loadHandler.cancel();
+    }
 
     if (this.updateHandler) {
       this.updateHandler.cancel();
@@ -85,9 +75,10 @@ class DHCPInfo extends Component {
    * @param attr {string} the event target attribute to use
    * @returns {function(Event)}
    */
-  onChange = (key, attr) => {
-    return e => {
-      const value = e.target[attr];
+  onChange = (key: string, attr: string) => {
+    return (e: ChangeEvent) => {
+      // @ts-ignore
+      const value: string = e.target[attr];
 
       this.setState(oldState => ({
         settings: {
@@ -103,7 +94,7 @@ class DHCPInfo extends Component {
    *
    * @param e the submit event
    */
-  saveSettings = e => {
+  saveSettings = (e: FormEvent) => {
     e.preventDefault();
 
     const { t } = this.props;
@@ -155,7 +146,7 @@ class DHCPInfo extends Component {
    * @param value the value to check
    * @param validator the validation function
    */
-  isSettingValid = (value, validator) => {
+  isSettingValid = (value: string, validator: (value: string) => boolean) => {
     return (
       (!this.state.settings.active && value.length === 0) || validator(value)
     );
@@ -180,10 +171,7 @@ class DHCPInfo extends Component {
       this.state.settings.router_ip,
       isValidIpv4
     );
-    const isLeaseTimeValid = this.isSettingValid(
-      this.state.settings.lease_time,
-      isPositiveNumber
-    );
+    const isLeaseTimeValid = this.state.settings.lease_time >= 0;
     const isDomainValid = this.isSettingValid(
       this.state.settings.domain,
       isValidHostname
@@ -262,7 +250,14 @@ class DHCPInfo extends Component {
                 id="leaseTime"
                 disabled={!this.state.settings.active}
                 value={this.state.settings.lease_time}
-                onChange={this.onChange("lease_time", "value")}
+                onChange={(e: ChangeEvent<HTMLInputElement>) =>
+                  this.setState(oldState => ({
+                    settings: {
+                      ...oldState.settings,
+                      lease_time: parseInt(e.target.value)
+                    }
+                  }))
+                }
                 invalid={!isLeaseTimeValid}
               />
               <InputGroupAddon addonType="append">Hours</InputGroupAddon>
diff --git a/src/components/settings/DNSInfo.js b/src/components/settings/DNSInfo.tsx
similarity index 79%
rename from src/components/settings/DNSInfo.js
rename to src/components/settings/DNSInfo.tsx
index 78a8fab..3a77b00 100644
--- a/src/components/settings/DNSInfo.js
+++ b/src/components/settings/DNSInfo.tsx
@@ -8,21 +8,31 @@
  * This file is copyright under the latest version of the EUPL.
  * Please see LICENSE file for your rights under this license. */
 
-import React, { Component } from "react";
-import { withNamespaces } from "react-i18next";
-import { ignoreCancel, makeCancelable } from "../../util";
-import api from "../../util/api";
+import React, { Component, FormEvent } from "react";
+import { WithNamespaces, withNamespaces } from "react-i18next";
+import { CancelablePromise, ignoreCancel, makeCancelable } from "../../util";
+import api, { ApiDnsSettings, ApiResultResponse } from "../../util/api";
 import DnsList from "./DnsList";
 import { Button, Col, Form, FormGroup } from "reactstrap";
-import ConditionalForwardingSettings from "./ConditionalForwardingSettings";
-import DnsOptionSettings from "./DnsOptionSettings";
-import Alert from "../common/Alert";
+import ConditionalForwardingSettings, { ConditionalForwardingObject } from "./ConditionalForwardingSettings";
+import DnsOptionSettings, { DnsOptionsObject } from "./DnsOptionSettings";
+import Alert, { AlertType } from "../common/Alert";
 import { isValidHostname, isValidIpv4 } from "../../util/validate";
 
-class DNSInfo extends Component {
-  state = {
+export interface DNSInfoState {
+  alertMessage: string;
+  alertType: AlertType;
+  showAlert: boolean;
+  processing: boolean;
+  upstreamDns: Array<string>;
+  conditionalForwarding: ConditionalForwardingObject;
+  options: DnsOptionsObject;
+}
+
+class DNSInfo extends Component<WithNamespaces, DNSInfoState> {
+  state: DNSInfoState = {
     alertMessage: "",
-    alertType: "",
+    alertType: "info",
     showAlert: false,
     processing: false,
     upstreamDns: [],
@@ -39,6 +49,9 @@ class DNSInfo extends Component {
     }
   };
 
+  private loadHandler: undefined | CancelablePromise<ApiDnsSettings>;
+  private updateHandler: undefined | CancelablePromise<ApiResultResponse>;
+
   loadDNSInfo = () => {
     this.loadHandler = makeCancelable(api.getDNSInfo());
     this.loadHandler.promise
@@ -70,26 +83,30 @@ class DNSInfo extends Component {
   }
 
   componentWillUnmount() {
-    this.loadHandler.cancel();
+    if (this.loadHandler) {
+      this.loadHandler.cancel();
+    }
   }
 
-  handleUpstreamAdd = upstream => {
+  handleUpstreamAdd = (upstream: string) => {
     this.setState({
       upstreamDns: this.state.upstreamDns.concat(upstream)
     });
   };
 
-  handleUpstreamRemove = upstream => {
+  handleUpstreamRemove = (upstream: string) => {
     this.setState({
       upstreamDns: this.state.upstreamDns.filter(item => item !== upstream)
     });
   };
 
-  handleConditionalForwardingUpdate = conditionalForwarding => {
+  handleConditionalForwardingUpdate = (
+    conditionalForwarding: ConditionalForwardingObject
+  ) => {
     this.setState({ conditionalForwarding });
   };
 
-  handleDnsOptionsUpdate = options => {
+  handleDnsOptionsUpdate = (options: DnsOptionsObject) => {
     this.setState({ options });
   };
 
@@ -98,7 +115,7 @@ class DNSInfo extends Component {
    *
    * @param e the submit event
    */
-  saveSettings = e => {
+  saveSettings = (e: FormEvent) => {
     e.preventDefault();
 
     const { t } = this.props;
@@ -157,7 +174,7 @@ class DNSInfo extends Component {
       });
   };
 
-  isCFSettingValid = (value, validator) => {
+  isCFSettingValid = (value: string, validator: (value: string) => boolean) => {
     return (
       (!this.state.conditionalForwarding.enabled && value.length === 0) ||
       validator(value)
diff --git a/src/components/settings/DnsList.js b/src/components/settings/DnsList.tsx
similarity index 76%
rename from src/components/settings/DnsList.js
rename to src/components/settings/DnsList.tsx
index dd3b8d3..5668536 100644
--- a/src/components/settings/DnsList.js
+++ b/src/components/settings/DnsList.tsx
@@ -9,12 +9,17 @@
  * Please see LICENSE file for your rights under this license. */
 
 import React from "react";
-import PropTypes from "prop-types";
 import { ListGroup } from "reactstrap";
 import DnsListItem from "./DnsListItem";
 import DnsListNewItem from "./DnsListNewItem";
 import { isValidIpv4OptionalPort } from "../../util/validate";
 
+export interface DnsListProps {
+  upstreams: Array<string>;
+  onAdd: (upstream: string) => void;
+  onRemove: (upstream: string) => void;
+}
+
 /**
  * Check if an upstream address is unique and valid
  *
@@ -22,10 +27,10 @@ import { isValidIpv4OptionalPort } from "../../util/validate";
  * @param upstreams the list of current upstreams
  * @returns {boolean} if the upstream address is unique and valid
  */
-export const isAddressValid = (address, upstreams) =>
+export const isAddressValid = (address: string, upstreams: Array<string>) =>
   !upstreams.includes(address) && isValidIpv4OptionalPort(address);
 
-const DnsList = ({ upstreams, onAdd, onRemove }) => (
+const DnsList = ({ upstreams, onAdd, onRemove }: DnsListProps) => (
   <ListGroup style={{ overflowY: "scroll", maxHeight: "350px" }}>
     {upstreams.map(upstream => (
       <DnsListItem
@@ -36,16 +41,10 @@ const DnsList = ({ upstreams, onAdd, onRemove }) => (
     ))}
     <DnsListNewItem
       onAdd={onAdd}
-      isValid={address => isAddressValid(address, upstreams)}
+      isValid={(address: string) => isAddressValid(address, upstreams)}
       upstreams={upstreams}
     />
   </ListGroup>
 );
 
-DnsList.propTypes = {
-  upstreams: PropTypes.arrayOf(PropTypes.string).isRequired,
-  onAdd: PropTypes.func.isRequired,
-  onRemove: PropTypes.func.isRequired
-};
-
 export default DnsList;
diff --git a/src/components/settings/DnsListItem.js b/src/components/settings/DnsListItem.tsx
similarity index 76%
rename from src/components/settings/DnsListItem.js
rename to src/components/settings/DnsListItem.tsx
index fecf7b2..d99ae9d 100644
--- a/src/components/settings/DnsListItem.js
+++ b/src/components/settings/DnsListItem.tsx
@@ -9,10 +9,14 @@
  * Please see LICENSE file for your rights under this license. */
 
 import React from "react";
-import PropTypes from "prop-types";
 import { Button, ListGroupItem } from "reactstrap";
 
-const DnsListItem = ({ address, onRemove }) => (
+export interface DnsListItemProps {
+  address: string,
+  onRemove: () => void;
+}
+
+const DnsListItem = ({ address, onRemove }: DnsListItemProps) => (
   <ListGroupItem>
     {address}
     <Button color="danger" size="sm" className="pull-right" onClick={onRemove}>
@@ -21,9 +25,4 @@ const DnsListItem = ({ address, onRemove }) => (
   </ListGroupItem>
 );
 
-DnsListItem.propTypes = {
-  address: PropTypes.string.isRequired,
-  onRemove: PropTypes.func.isRequired
-};
-
 export default DnsListItem;
diff --git a/src/components/settings/DnsListNewItem.js b/src/components/settings/DnsListNewItem.tsx
similarity index 76%
rename from src/components/settings/DnsListNewItem.js
rename to src/components/settings/DnsListNewItem.tsx
index 3f4621a..54e3a92 100644
--- a/src/components/settings/DnsListNewItem.js
+++ b/src/components/settings/DnsListNewItem.tsx
@@ -8,30 +8,39 @@
  * This file is copyright under the latest version of the EUPL.
  * Please see LICENSE file for your rights under this license. */
 
-import React, { Component } from "react";
-import PropTypes from "prop-types";
+import React, { Component, RefObject } from "react";
 import { Button, InputGroup, InputGroupAddon, ListGroupItem } from "reactstrap";
 import { Typeahead } from "react-bootstrap-typeahead";
-import { withNamespaces } from "react-i18next";
-import { preconfiguredUpstreamOptions } from "./preconfiguredUpstreams";
+import { WithNamespaces, withNamespaces } from "react-i18next";
+import { PreconfiguredUpstreamOption, preconfiguredUpstreamOptions } from "./preconfiguredUpstreams";
+
+export interface DnsListNewItemProps {
+  onAdd: (address: string) => void;
+  isValid: (address: string) => boolean;
+  upstreams: Array<string>;
+}
+
+export interface DnsListNewItemState {
+  address: string;
+  selected: Array<PreconfiguredUpstreamOption>;
+}
 
 /**
  * A component to add upstream DNS servers. The servers are either selected from
  * a list of preconfigured upstreams, or custom servers can be input.
  */
-class DnsListNewItem extends Component {
-  static propTypes = {
-    onAdd: PropTypes.func.isRequired,
-    isValid: PropTypes.func.isRequired,
-    upstreams: PropTypes.arrayOf(PropTypes.string).isRequired
-  };
-
-  state = {
+class DnsListNewItem extends Component<
+  DnsListNewItemProps & WithNamespaces,
+  DnsListNewItemState
+> {
+  state: DnsListNewItemState = {
     address: "",
     selected: []
   };
 
-  constructor(props) {
+  private readonly typeahead: RefObject<any>;
+
+  constructor(props: DnsListNewItemProps & WithNamespaces) {
     super(props);
     this.typeahead = React.createRef();
   }
diff --git a/src/components/settings/DnsOptionSettings.js b/src/components/settings/DnsOptionSettings.tsx
similarity index 83%
rename from src/components/settings/DnsOptionSettings.js
rename to src/components/settings/DnsOptionSettings.tsx
index 7faa201..60a0bab 100644
--- a/src/components/settings/DnsOptionSettings.js
+++ b/src/components/settings/DnsOptionSettings.tsx
@@ -11,8 +11,26 @@
 import React, { Fragment } from "react";
 import PropTypes from "prop-types";
 import { Col, FormGroup, Input, Label } from "reactstrap";
+import i18next from "i18next";
 
-const DnsOptionSettings = ({ settings, onUpdate, t }) => (
+export interface DnsOptionsObject {
+  fqdnRequired: boolean;
+  bogusPriv: boolean;
+  dnssec: boolean;
+  listeningType: string;
+}
+
+export interface DnsOptionSettingsProps {
+  settings: DnsOptionsObject;
+  onUpdate: (settings: DnsOptionsObject) => void;
+  t: i18next.TranslationFunction;
+}
+
+const DnsOptionSettings = ({
+  settings,
+  onUpdate,
+  t
+}: DnsOptionSettingsProps) => (
   <Fragment>
     <FormGroup row>
       <Label for="listeningBehavior" sm={5}>
diff --git a/src/components/settings/FTLInfo.js b/src/components/settings/FTLInfo.tsx
similarity index 74%
rename from src/components/settings/FTLInfo.js
rename to src/components/settings/FTLInfo.tsx
index 5a272b4..9c0bedf 100644
--- a/src/components/settings/FTLInfo.js
+++ b/src/components/settings/FTLInfo.tsx
@@ -9,18 +9,17 @@
  * Please see LICENSE file for your rights under this license. */
 
 import React, { Component } from "react";
-import PropTypes from "prop-types";
-import { withNamespaces } from "react-i18next";
-import api from "../../util/api";
+import { WithNamespaces, withNamespaces } from "react-i18next";
+import api, { ApiFtlDbResponse } from "../../util/api";
 import { WithAPIData } from "../common/WithAPIData";
 
-class FTLInfo extends Component {
-  static propTypes = {
-    fileSize: PropTypes.number.isRequired,
-    queries: PropTypes.number.isRequired,
-    sqliteVersion: PropTypes.string.isRequired
-  };
+export interface FTLInfoProps {
+  fileSize: number,
+  queries: number,
+  sqliteVersion: string
+}
 
+class FTLInfo extends Component<FTLInfoProps & WithNamespaces, {}> {
   render() {
     const { t } = this.props;
 
@@ -36,7 +35,7 @@ class FTLInfo extends Component {
   }
 }
 
-export const transformData = data => ({
+export const transformData = (data: ApiFtlDbResponse): FTLInfoProps => ({
   fileSize: data.filesize,
   queries: data.queries,
   sqliteVersion: data.sqlite_version
@@ -50,11 +49,12 @@ export const initialData = {
 
 export const TranslatedFTLInfo = withNamespaces(["settings"])(FTLInfo);
 
-export default props => (
+export default (props: any) => (
   <WithAPIData
     apiCall={api.getFTLdb}
     repeatOptions={{
-      interval: 600000
+      interval: 600000,
+      ignoreCancel: true
     }}
     renderInitial={() => <TranslatedFTLInfo {...initialData} {...props} />}
     renderOk={data => <TranslatedFTLInfo {...transformData(data)} {...props} />}
diff --git a/src/components/settings/NetworkInfo.js b/src/components/settings/NetworkInfo.tsx
similarity index 84%
rename from src/components/settings/NetworkInfo.js
rename to src/components/settings/NetworkInfo.tsx
index 89038ae..0f4cc8f 100644
--- a/src/components/settings/NetworkInfo.js
+++ b/src/components/settings/NetworkInfo.tsx
@@ -9,20 +9,19 @@
  * Please see LICENSE file for your rights under this license. */
 
 import React, { Component } from "react";
-import PropTypes from "prop-types";
-import { withNamespaces } from "react-i18next";
-import api from "../../util/api";
+import { Subtract, WithNamespaces, withNamespaces } from "react-i18next";
+import api, { ApiNetworkSettings } from "../../util/api";
 import { Col, Form, FormGroup, Input, Label } from "reactstrap";
 import { WithAPIData } from "../common/WithAPIData";
 
-class NetworkInfo extends Component {
-  static propTypes = {
-    interface: PropTypes.string.isRequired,
-    ipv4Address: PropTypes.string.isRequired,
-    ipv6Address: PropTypes.string.isRequired,
-    hostname: PropTypes.string.isRequired
-  };
+export interface NetworkInfoProps extends WithNamespaces {
+  interface: string;
+  ipv4Address: string;
+  ipv6Address: string;
+  hostname: string;
+}
 
+class NetworkInfo extends Component<NetworkInfoProps, {}> {
   render() {
     const { t } = this.props;
 
@@ -85,7 +84,9 @@ class NetworkInfo extends Component {
   }
 }
 
-export const transformData = data => ({
+export const transformData = (
+  data: ApiNetworkSettings
+): Subtract<NetworkInfoProps, WithNamespaces> => ({
   interface: data.interface,
   ipv4Address: data.ipv4_address,
   ipv6Address: data.ipv6_address,
@@ -103,7 +104,7 @@ export const TranslatedNetworkInfo = withNamespaces(["common", "settings"])(
   NetworkInfo
 );
 
-export default props => (
+export default (props: any) => (
   <WithAPIData
     apiCall={api.getNetworkInfo}
     repeatOptions={{
diff --git a/src/components/settings/PreferenceSettings.js b/src/components/settings/PreferenceSettings.tsx
similarity index 79%
rename from src/components/settings/PreferenceSettings.js
rename to src/components/settings/PreferenceSettings.tsx
index 36964e2..aae6826 100644
--- a/src/components/settings/PreferenceSettings.js
+++ b/src/components/settings/PreferenceSettings.tsx
@@ -8,44 +8,50 @@
  * This file is copyright under the latest version of the EUPL.
  * Please see LICENSE file for your rights under this license. */
 
-import React, { Component } from "react";
-import PropTypes from "prop-types";
-import { withNamespaces } from "react-i18next";
-import { ignoreCancel, makeCancelable } from "../../util";
-import api from "../../util/api";
-import Alert from "../common/Alert";
+import React, { ChangeEvent, Component, FormEvent } from "react";
+import { WithNamespaces, withNamespaces } from "react-i18next";
+import { CancelablePromise, ignoreCancel, makeCancelable } from "../../util";
+import api, { ApiPreferences, ApiResultResponse } from "../../util/api";
+import Alert, { AlertType } from "../common/Alert";
 import { Button, Col, Form, FormGroup, Input, Label } from "reactstrap";
 import { PreferencesContext } from "../common/context";
-import languages from "../../languages";
+import languages from "../../languages.json";
 import i18n from "i18next";
 
-class PreferenceSettings extends Component {
-  static propTypes = {
-    settings: PropTypes.shape({
-      layout: PropTypes.string.isRequired
-    }),
-    refresh: PropTypes.func.isRequired
-  };
+export interface PreferenceSettingsProps {
+  settings: ApiPreferences;
+  refresh: (preferences?: ApiPreferences) => void;
+}
 
-  state = {
+export interface PreferenceSettingsState {
+  alertMessage: string;
+  alertType: AlertType;
+  showAlert: boolean;
+  processing: boolean;
+  settings: ApiPreferences;
+}
+
+class PreferenceSettings extends Component<
+  PreferenceSettingsProps & WithNamespaces,
+  PreferenceSettingsState
+> {
+  state: PreferenceSettingsState = {
     alertMessage: "",
-    alertType: "",
+    alertType: "info",
     showAlert: false,
     processing: false,
     // Initial value is the current settings
     settings: this.props.settings
   };
 
+  private loadHandler: undefined | CancelablePromise<ApiPreferences>;
+  private updateHandler: undefined | CancelablePromise<ApiResultResponse>;
+
   loadPreferences = () => {
     this.loadHandler = makeCancelable(api.getPreferences());
     this.loadHandler.promise
       .then(res => {
-        this.setState({
-          settings: {
-            layout: res.layout,
-            language: res.language
-          }
-        });
+        this.setState({ settings: res });
       })
       .catch(ignoreCancel);
   };
@@ -55,7 +61,9 @@ class PreferenceSettings extends Component {
   }
 
   componentWillUnmount() {
-    this.loadHandler.cancel();
+    if (this.loadHandler) {
+      this.loadHandler.cancel();
+    }
 
     if (this.updateHandler) {
       this.updateHandler.cancel();
@@ -70,9 +78,10 @@ class PreferenceSettings extends Component {
    * @param attr {string} the event target attribute to use
    * @returns {function(Event)}
    */
-  onChange = (key, attr) => {
-    return e => {
-      const value = e.target[attr];
+  onChange = (key: string, attr: string) => {
+    return (e: ChangeEvent) => {
+      // @ts-ignore
+      const value: string = e.target[attr];
 
       this.setState(oldState => ({
         settings: {
@@ -88,7 +97,7 @@ class PreferenceSettings extends Component {
    *
    * @param e the submit event
    */
-  saveSettings = e => {
+  saveSettings = (e: FormEvent) => {
     e.preventDefault();
 
     const { t } = this.props;
diff --git a/src/components/settings/VersionCard.js b/src/components/settings/VersionCard.tsx
similarity index 84%
rename from src/components/settings/VersionCard.js
rename to src/components/settings/VersionCard.tsx
index f8c201f..6c03e74 100644
--- a/src/components/settings/VersionCard.js
+++ b/src/components/settings/VersionCard.tsx
@@ -9,19 +9,23 @@
  * Please see LICENSE file for your rights under this license. */
 
 import React, { Component } from "react";
-import { withNamespaces } from "react-i18next";
-import PropTypes from "prop-types";
+import { WithNamespaces, withNamespaces } from "react-i18next";
 import { Collapse } from "reactstrap";
 
-class VersionCard extends Component {
-  static propTypes = {
-    branch: PropTypes.string.isRequired,
-    hash: PropTypes.string.isRequired,
-    name: PropTypes.string.isRequired,
-    tag: PropTypes.string.isRequired
-  };
+export interface VersionCardProps extends WithNamespaces {
+  branch: string;
+  hash: string;
+  name: string;
+  tag: string;
+  icon: string;
+}
 
-  state = {
+export interface VersionCardState {
+  collapsed: boolean
+}
+
+class VersionCard extends Component<VersionCardProps, VersionCardState> {
+  state: VersionCardState = {
     collapsed: true
   };
 
diff --git a/src/components/settings/VersionInfo.js b/src/components/settings/VersionInfo.tsx
similarity index 79%
rename from src/components/settings/VersionInfo.js
rename to src/components/settings/VersionInfo.tsx
index f88bf0e..6adf7de 100644
--- a/src/components/settings/VersionInfo.js
+++ b/src/components/settings/VersionInfo.tsx
@@ -9,26 +9,12 @@
  * Please see LICENSE file for your rights under this license. */
 
 import React, { Component } from "react";
-import PropTypes from "prop-types";
-import { withNamespaces } from "react-i18next";
-import api from "../../util/api";
+import { WithNamespaces, withNamespaces } from "react-i18next";
+import api, { ApiVersions } from "../../util/api";
 import VersionCard from "./VersionCard";
 import { WithAPIData } from "../common/WithAPIData";
 
-class VersionInfo extends Component {
-  static versionPropType = PropTypes.shape({
-    branch: PropTypes.string.isRequired,
-    hash: PropTypes.string.isRequired,
-    tag: PropTypes.string.isRequired
-  }).isRequired;
-
-  static propTypes = {
-    api: VersionInfo.versionPropType,
-    core: VersionInfo.versionPropType,
-    ftl: VersionInfo.versionPropType,
-    web: VersionInfo.versionPropType
-  };
-
+class VersionInfo extends Component<ApiVersions & WithNamespaces, {}> {
   render() {
     const { t } = this.props;
 
@@ -75,7 +61,7 @@ class VersionInfo extends Component {
   }
 }
 
-export const initialData = {
+export const initialData: ApiVersions = {
   api: {
     branch: "unknown",
     hash: "unknown",
@@ -100,10 +86,10 @@ export const initialData = {
 
 export const TranslatedVersionInfo = withNamespaces(["common"])(VersionInfo);
 
-export default props => (
+export default (props: any) => (
   <WithAPIData
     apiCall={api.getVersion}
-    repeatOptions={{ interval: 600000 }}
+    repeatOptions={{ interval: 600000, ignoreCancel: true }}
     renderInitial={() => <TranslatedVersionInfo {...initialData} {...props} />}
     renderOk={data => <TranslatedVersionInfo {...data} {...props} />}
     renderErr={() => <TranslatedVersionInfo {...initialData} {...props} />}
diff --git a/src/components/settings/__tests__/DHCPInfo.test.js b/src/components/settings/__tests__/DHCPInfo.test.tsx
similarity index 85%
rename from src/components/settings/__tests__/DHCPInfo.test.js
rename to src/components/settings/__tests__/DHCPInfo.test.tsx
index 0c4b479..176536b 100644
--- a/src/components/settings/__tests__/DHCPInfo.test.js
+++ b/src/components/settings/__tests__/DHCPInfo.test.tsx
@@ -9,9 +9,12 @@
  * Please see LICENSE file for your rights under this license. */
 
 import React from "react";
-import { shallow } from "enzyme";
-import DHCPInfo from "../DHCPInfo";
+import { shallow, ShallowWrapper } from "enzyme";
+import DHCPInfo, { DHCPInfoState } from "../DHCPInfo";
 import fetchMock from "fetch-mock";
+import { WithNamespaces } from "react-i18next";
+
+const tick = global.tick;
 
 const endpoint = "/admin/api/settings/dhcp";
 const fakeData = {
@@ -51,7 +54,9 @@ it("disables the apply button if an input is invalid", async () => {
 it("disables inputs only when DHCP is not enabled", async () => {
   fetchMock.mock(endpoint, { body: fakeData });
 
-  const wrapper = shallow(<DHCPInfo />);
+  const wrapper: ShallowWrapper<WithNamespaces, DHCPInfoState> = shallow(
+    <DHCPInfo />
+  );
 
   await tick();
   wrapper.update();
@@ -69,7 +74,9 @@ it("disables the apply button when processing setting update", async () => {
   fetchMock.get(endpoint, { body: fakeData });
   fetchMock.put(endpoint, { body: { status: "success" } });
 
-  const wrapper = shallow(<DHCPInfo />);
+  const wrapper: ShallowWrapper<WithNamespaces, DHCPInfoState> = shallow(
+    <DHCPInfo />
+  );
 
   await tick();
 
@@ -86,7 +93,9 @@ it("sends the correct data to the API when apply is clicked", async () => {
   fetchMock.get(endpoint, { body: fakeData });
   fetchMock.put(endpoint, { body: { status: "success" } });
 
-  const wrapper = shallow(<DHCPInfo />);
+  const wrapper: ShallowWrapper<WithNamespaces, DHCPInfoState> = shallow(
+    <DHCPInfo />
+  );
 
   await tick();
 
@@ -99,9 +108,9 @@ it("sends the correct data to the API when apply is clicked", async () => {
   expect(wrapper.find("Button")).toBeDisabled();
 
   // The output of lastCall is [url, request]
-  const updateRequest = fetchMock.lastCall(endpoint)[1];
+  const updateRequest = fetchMock.lastCall(endpoint)![1];
 
-  expect(JSON.parse(updateRequest.body)).toEqual(fakeData);
+  expect(JSON.parse(updateRequest!.body as string)).toEqual(fakeData);
 });
 
 it("shows a success message after successfully saving settings", async () => {
diff --git a/src/components/settings/preconfiguredUpstreams.js b/src/components/settings/preconfiguredUpstreams.tsx
similarity index 87%
rename from src/components/settings/preconfiguredUpstreams.js
rename to src/components/settings/preconfiguredUpstreams.tsx
index 961e150..639a694 100644
--- a/src/components/settings/preconfiguredUpstreams.js
+++ b/src/components/settings/preconfiguredUpstreams.tsx
@@ -8,11 +8,19 @@
  * This file is copyright under the latest version of the EUPL.
  * Please see LICENSE file for your rights under this license. */
 
+export interface PreconfiguredUpstream {
+  name: string;
+  primaryIpv4: string;
+  secondaryIpv4: string;
+  primaryIpv6: string;
+  secondaryIpv6: string;
+}
+
 /**
  * A list of preconfigured upstream DNS servers. Each item has primary and
  * secondary IPv4 and IPv6 server entries. Some addresses may be empty.
  */
-export const preconfiguredUpstreams = [
+export const preconfiguredUpstreams: Array<PreconfiguredUpstream> = [
   {
     name: "OpenDNS (ECS)",
     primaryIpv4: "208.67.222.222",
@@ -78,6 +86,11 @@ export const preconfiguredUpstreams = [
   }
 ];
 
+export interface PreconfiguredUpstreamOption {
+  label: string;
+  address: string;
+}
+
 /**
  * The preconfigured servers, but with an entry for each address. This is used
  * when displaying the servers in a list.
@@ -85,12 +98,12 @@ export const preconfiguredUpstreams = [
 export const preconfiguredUpstreamOptions = preconfiguredUpstreams.flatMap(
   upstream => {
     // Parse the upstream address information into the new format
-    const parseUpstream = (address, order, type) => ({
+    const parseUpstream = (address: string, order: string, type: string) => ({
       label: upstream.name + " " + order + " " + type + " (" + address + ")",
       address
     });
 
-    let parsedUpstreams = [];
+    let parsedUpstreams: Array<PreconfiguredUpstreamOption> = [];
 
     if (upstream.primaryIpv4.length > 0) {
       parsedUpstreams.push(
diff --git a/src/util/api.tsx b/src/util/api.tsx
index b5e7113..e31e9d9 100644
--- a/src/util/api.tsx
+++ b/src/util/api.tsx
@@ -24,46 +24,88 @@ export interface ApiQuery {
 
 export interface ApiHistoryResponse {
   cursor: null | string;
-  history: Array<ApiQuery>
+  history: Array<ApiQuery>;
+}
+
+export interface ApiNetworkSettings {
+  interface: string;
+  ipv4_address: string;
+  ipv6_address: string;
+  hostname: string;
+}
+
+export interface ApiVersion {
+  branch: string;
+  hash: string;
+  tag: string;
+}
+
+export interface ApiVersions {
+  api: ApiVersion;
+  core: ApiVersion;
+  ftl: ApiVersion;
+  web: ApiVersion;
 }
 
 export interface ApiDnsSettings {
-  upstream_dns: Array<string>,
+  upstream_dns: Array<string>;
   options: {
-    fqdn_required: boolean,
-    bogus_priv: boolean,
-    dnssec: boolean,
-    listening_type: string
-  },
+    fqdn_required: boolean;
+    bogus_priv: boolean;
+    dnssec: boolean;
+    listening_type: string;
+  };
   conditional_forwarding: {
-    enabled: boolean,
-    router_ip: string,
-    domain: string
-  }
+    enabled: boolean;
+    router_ip: string;
+    domain: string;
+  };
 }
 
 export interface ApiDhcpSettings {
-  active: boolean,
-  ip_start: string,
-  ip_end: string,
-  router_ip: string,
-  lease_time: number,
-  domain: string,
-  ipv6_support: boolean
+  active: boolean;
+  ip_start: string;
+  ip_end: string;
+  router_ip: string;
+  lease_time: number;
+  domain: string;
+  ipv6_support: boolean;
 }
 
+export interface ApiFtlDbResponse {
+  filesize: number;
+  queries: number;
+  sqlite_version: string;
+}
+
+export interface ApiSuccessResponse {
+  status: "success";
+}
+
+export interface ApiError {
+  key: string;
+  message: string;
+  data: any;
+}
+
+export interface ApiErrorResponse {
+  error: ApiError;
+}
+
+export type ApiResultResponse = ApiSuccessResponse | ApiErrorResponse;
+
 export type WebLayout = "boxed" | "traditional";
 
 export interface ApiPreferences {
-  layout: WebLayout,
-  language: string
+  layout: WebLayout;
+  language: string;
 }
 
 export type Status = "enabled" | "disabled" | "unknown";
 export type StatusAction = "enable" | "disable";
 
 export interface ApiStatus {
-  status: Status
+  status: Status;
 }
 
 export default {
@@ -142,13 +184,13 @@ export default {
   setStatus(action: StatusAction, time: number | null = null) {
     return http.post("dns/status", { action, time });
   },
-  getNetworkInfo() {
+  getNetworkInfo(): Promise<ApiNetworkSettings> {
     return http.get("settings/network");
   },
-  getVersion() {
+  getVersion(): Promise<ApiVersions> {
     return http.get("version");
   },
-  getFTLdb() {
+  getFTLdb(): Promise<ApiFtlDbResponse> {
     return http.get("settings/ftldb");
   },
   getDNSInfo(): Promise<ApiDnsSettings> {