diff --git a/ts/Intl.d.ts b/ts/Intl.d.ts
index dd1bccf1a..0553a75b7 100644
--- a/ts/Intl.d.ts
+++ b/ts/Intl.d.ts
@@ -1,4 +1,4 @@
-// Copyright 2021 Signal Messenger, LLC
+// Copyright 2021-2022 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
 declare namespace Intl {
@@ -18,11 +18,11 @@ declare namespace Intl {
     isWordLike?: boolean;
   };
 
-  interface Segments {
+  type Segments = {
     containing(index: number): SegmentData;
 
     [Symbol.iterator](): Iterator<SegmentData>;
-  }
+  };
 
   // `Intl.Segmenter` is not yet in TypeScript's type definitions, so we add it.
   class Segmenter {
diff --git a/ts/firstline.d.ts b/ts/firstline.d.ts
index e2b3362be..97be1e299 100644
--- a/ts/firstline.d.ts
+++ b/ts/firstline.d.ts
@@ -1,11 +1,11 @@
-// Copyright 2021 Signal Messenger, LLC
+// Copyright 2021-2022 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
 declare module 'firstline' {
-  interface FirstLineOpts {
+  type FirstLineOpts = {
     encoding?: BufferEncoding;
     lineEnding?: '\n';
-  }
+  };
 
   export default function firstLine(
     filePath: string,
diff --git a/ts/mp4box.d.ts b/ts/mp4box.d.ts
index fa8ce3d04..a55da60c0 100644
--- a/ts/mp4box.d.ts
+++ b/ts/mp4box.d.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 
 declare module 'mp4box' {
-  interface MP4MediaTrack {
+  type MP4MediaTrack = {
     alternate_group: number;
     bitrate: number;
     codec: string;
@@ -18,30 +18,30 @@ declare module 'mp4box' {
     track_height: number;
     track_width: number;
     volume: number;
-  }
+  };
 
-  interface MP4VideoData {
+  type MP4VideoData = {
     height: number;
     width: number;
-  }
+  };
 
-  interface MP4VideoTrack extends MP4MediaTrack {
+  type MP4VideoTrack = MP4MediaTrack & {
     video: MP4VideoData;
-  }
+  };
 
-  interface MP4AudioData {
+  type MP4AudioData = {
     channel_count: number;
     sample_rate: number;
     sample_size: number;
-  }
+  };
 
-  interface MP4AudioTrack extends MP4MediaTrack {
+  type MP4AudioTrack = MP4MediaTrack & {
     audio: MP4AudioData;
-  }
+  };
 
   type MP4Track = MP4VideoTrack | MP4AudioTrack;
 
-  interface MP4Info {
+  type MP4Info = {
     brands: Array<string>;
     created: Date;
     duration: number;
@@ -53,16 +53,16 @@ declare module 'mp4box' {
     modified: Date;
     timescale: number;
     tracks: Array<MP4Track>;
-  }
+  };
 
   export type MP4ArrayBuffer = ArrayBuffer & { fileStart: number };
 
-  export interface MP4File {
+  export type MP4File = {
     appendBuffer(data: MP4ArrayBuffer): number;
     flush(): void;
     onError?: (e: string) => void;
     onReady?: (info: MP4Info) => void;
-  }
+  };
 
   export function createFile(): MP4File;
 }
diff --git a/ts/textsecure/Types.d.ts b/ts/textsecure/Types.d.ts
index a973ce07d..e11b80e0e 100644
--- a/ts/textsecure/Types.d.ts
+++ b/ts/textsecure/Types.d.ts
@@ -250,7 +250,7 @@ export type CustomError = Error & {
   number?: string;
 };
 
-export interface CallbackResultType {
+export type CallbackResultType = {
   successfulIdentifiers?: Array<string>;
   failoverIdentifiers?: Array<string>;
   errors?: Array<CustomError>;
@@ -268,11 +268,11 @@ export interface CallbackResultType {
   recipients?: Record<string, Array<number>>;
   urgent?: boolean;
   hasPniSignatureMessage?: boolean;
-}
+};
 
-export interface IRequestHandler {
+export type IRequestHandler = {
   handleRequest(request: IncomingWebSocketRequest): void;
-}
+};
 
 export type PniKeyMaterialType = Readonly<{
   identityKeyPair: Uint8Array;
diff --git a/ts/types/Storage.d.ts b/ts/types/Storage.d.ts
index ee071d407..80251bf81 100644
--- a/ts/types/Storage.d.ts
+++ b/ts/types/Storage.d.ts
@@ -1,4 +1,4 @@
-// Copyright 2020-2021 Signal Messenger, LLC
+// Copyright 2020-2022 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
 import type { AudioDevice } from 'ringrtc';
@@ -145,7 +145,7 @@ export type StorageAccessType = {
   'challenge:retry-message-ids': never;
 };
 
-export interface StorageInterface {
+export type StorageInterface = {
   onready(callback: () => void): void;
 
   get<K extends keyof StorageAccessType, V extends StorageAccessType[K]>(
@@ -163,4 +163,4 @@ export interface StorageInterface {
   ): Promise<void>;
 
   remove<K extends keyof StorageAccessType>(key: K): Promise<void>;
-}
+};