diff --git a/examples/node-prerecorded/index.js b/examples/node-prerecorded/index.js
index d15f128c..0c2d784f 100644
--- a/examples/node-prerecorded/index.js
+++ b/examples/node-prerecorded/index.js
@@ -21,10 +21,7 @@ const readstream = async () => {
   const deepgram = createClient(process.env.DEEPGRAM_API_KEY);
 
   const { result, error } = await deepgram.listen.prerecorded.transcribeFile(
-    {
-      stream: fs.createReadStream("./examples/nasa.mp4"),
-      mimetype: "audio/mp4",
-    },
+    fs.createReadStream("./examples/nasa.mp4"),
     {
       model: "nova",
     }
@@ -38,10 +35,7 @@ const buffer = async () => {
   const deepgram = createClient(process.env.DEEPGRAM_API_KEY);
 
   const { result, error } = await deepgram.listen.prerecorded.transcribeFile(
-    {
-      buffer: fs.readFileSync("./examples/nasa.mp4"),
-      mimetype: "audio/mp4",
-    },
+    fs.readFileSync("./examples/nasa.mp4"),
     {
       model: "nova",
     }
@@ -51,6 +45,8 @@ const buffer = async () => {
   if (!error) console.log(result);
 };
 
-url();
-readstream();
-buffer();
+(async () => {
+  await url();
+  await readstream();
+  await buffer();
+})();
diff --git a/src/lib/constants.ts b/src/lib/constants.ts
index 4cab1aa0..34e3b57e 100644
--- a/src/lib/constants.ts
+++ b/src/lib/constants.ts
@@ -4,7 +4,6 @@ import { version } from "./version";
 export const DEFAULT_HEADERS = {
   "X-Client-Info": `@deepgram/sdk; ${isBrowser() ? "browser" : "server"}; v${version}`,
   "User-Agent": `@deepgram/sdk/${version}`,
-  "Content-Type": "application/json",
 };
 
 export const DEFAULT_URL = "api.deepgram.com";
diff --git a/src/lib/helpers.ts b/src/lib/helpers.ts
index 1c008027..18463284 100644
--- a/src/lib/helpers.ts
+++ b/src/lib/helpers.ts
@@ -1,11 +1,6 @@
 import { Headers as CrossFetchHeaders } from "cross-fetch";
-import {
-  BufferSource,
-  DeepgramClientOptions,
-  PrerecordedSource,
-  ReadStreamSource,
-  UrlSource,
-} from "./types";
+import { DeepgramClientOptions, FileSource, PrerecordedSource, UrlSource } from "./types";
+import { Readable } from "stream";
 
 export function stripTrailingSlash(url: string): string {
   return url.replace(/\/$/, "");
@@ -59,18 +54,20 @@ export const isUrlSource = (providedSource: PrerecordedSource): providedSource i
   return false;
 };
 
-export const isBufferSource = (
-  providedSource: PrerecordedSource
-): providedSource is BufferSource => {
-  if ((providedSource as BufferSource).buffer) return true;
+export const isFileSource = (providedSource: PrerecordedSource): providedSource is FileSource => {
+  if (isReadStreamSource(providedSource) || isBufferSource(providedSource)) return true;
 
   return false;
 };
 
-export const isReadStreamSource = (
-  providedSource: PrerecordedSource
-): providedSource is ReadStreamSource => {
-  if ((providedSource as ReadStreamSource).stream) return true;
+const isBufferSource = (providedSource: PrerecordedSource): providedSource is Buffer => {
+  if (providedSource as Buffer) return true;
+
+  return false;
+};
+
+const isReadStreamSource = (providedSource: PrerecordedSource): providedSource is Readable => {
+  if (providedSource as Readable) return true;
 
   return false;
 };
diff --git a/src/lib/types/PrerecordedSource.ts b/src/lib/types/PrerecordedSource.ts
index 8eb3864d..e85d5c02 100644
--- a/src/lib/types/PrerecordedSource.ts
+++ b/src/lib/types/PrerecordedSource.ts
@@ -1,19 +1,9 @@
 import { Readable } from "stream";
 
-export type PrerecordedSource = UrlSource | BufferSource | ReadStreamSource;
+export type PrerecordedSource = UrlSource | Buffer | Readable;
 
-export type FileSource = BufferSource | ReadStreamSource;
-
-export interface ReadStreamSource {
-  stream: Readable;
-  mimetype: string;
-}
+export type FileSource = Buffer | Readable;
 
 export interface UrlSource {
   url: string;
 }
-
-export interface BufferSource {
-  buffer: Buffer;
-  mimetype: string;
-}
diff --git a/src/lib/types/index.ts b/src/lib/types/index.ts
index ae3e9873..104eff9d 100644
--- a/src/lib/types/index.ts
+++ b/src/lib/types/index.ts
@@ -32,13 +32,7 @@ export type { LiveConfigOptions } from "./LiveConfigOptions";
 export type { LiveMetadataEvent } from "./LiveMetadataEvent";
 export type { LiveTranscriptionEvent } from "./LiveTranscriptionEvent";
 export type { MessageResponse } from "./MessageResponse";
-export type {
-  BufferSource,
-  FileSource,
-  PrerecordedSource,
-  ReadStreamSource,
-  UrlSource,
-} from "./PrerecordedSource";
+export type { FileSource, PrerecordedSource, UrlSource } from "./PrerecordedSource";
 export type { SendProjectInviteOptions } from "./SendProjectInviteOptions";
 export type { SyncPrerecordedResponse } from "./SyncPrerecordedResponse";
 export type { TranscriptionOptions, PrerecordedOptions, LiveOptions } from "./TranscriptionOptions";
diff --git a/src/packages/AbstractRestfulClient.ts b/src/packages/AbstractRestfulClient.ts
index 8185ff75..1411ef10 100644
--- a/src/packages/AbstractRestfulClient.ts
+++ b/src/packages/AbstractRestfulClient.ts
@@ -48,7 +48,7 @@ export class AbstractRestfulClient {
       return params;
     }
 
-    params.headers = { "Content-Type": "application/json", ...options?.headers };
+    params.headers = { ...options?.headers };
     params.body = body;
     return { ...params, ...parameters, duplex: "half" };
   }
diff --git a/src/packages/PrerecordedClient.ts b/src/packages/PrerecordedClient.ts
index f36a7f6d..8342fef6 100644
--- a/src/packages/PrerecordedClient.ts
+++ b/src/packages/PrerecordedClient.ts
@@ -1,11 +1,5 @@
 import { AbstractRestfulClient } from "./AbstractRestfulClient";
-import {
-  CallbackUrl,
-  appendSearchParams,
-  isBufferSource,
-  isReadStreamSource,
-  isUrlSource,
-} from "../lib/helpers";
+import { CallbackUrl, appendSearchParams, isFileSource, isUrlSource } from "../lib/helpers";
 import { DeepgramError, isDeepgramError } from "../lib/errors";
 import type {
   AsyncPrerecordedResponse,
@@ -24,7 +18,10 @@ export class PrerecordedClient extends AbstractRestfulClient {
     endpoint = "v1/listen"
   ): Promise<DeepgramResponse<SyncPrerecordedResponse>> {
     try {
+      this.headers["Content-Type"] = "application/json";
+
       let body;
+
       if (isUrlSource(source)) {
         body = JSON.stringify(source);
       } else {
@@ -62,19 +59,13 @@ export class PrerecordedClient extends AbstractRestfulClient {
     endpoint = "v1/listen"
   ): Promise<DeepgramResponse<SyncPrerecordedResponse>> {
     try {
-      if (source.mimetype === undefined || source.mimetype.length === 0) {
-        throw new DeepgramError(
-          "Mimetype must be provided if the source is a Buffer or a Readable"
-        );
-      }
-
-      this.headers["Content-Type"] = source.mimetype;
+      // deepgram ignores the mimetype if it's not `application/json`
+      this.headers["Content-Type"] = "deepgram/audio+video";
 
       let body;
-      if (isBufferSource(source)) {
-        body = source.buffer;
-      } else if (isReadStreamSource(source)) {
-        body = source.stream;
+
+      if (isFileSource(source)) {
+        body = source;
       } else {
         throw new DeepgramError("Unknown transcription source type");
       }
@@ -111,7 +102,10 @@ export class PrerecordedClient extends AbstractRestfulClient {
     endpoint = "v1/listen"
   ): Promise<DeepgramResponse<AsyncPrerecordedResponse>> {
     try {
+      this.headers["Content-Type"] = "application/json";
+
       let body;
+
       if (isUrlSource(source)) {
         body = JSON.stringify(source);
       } else {
@@ -147,19 +141,13 @@ export class PrerecordedClient extends AbstractRestfulClient {
     endpoint = "v1/listen"
   ): Promise<DeepgramResponse<AsyncPrerecordedResponse>> {
     try {
-      if (source.mimetype === undefined || source.mimetype.length === 0) {
-        throw new DeepgramError(
-          "Mimetype must be provided if the source is a Buffer or a Readable"
-        );
-      }
-
-      this.headers["Content-Type"] = source.mimetype;
+      // deepgram ignores the mimetype if it's not `application/json`
+      this.headers["Content-Type"] = "deepgram/audio+video";
 
       let body;
-      if (isBufferSource(source)) {
-        body = source.buffer;
-      } else if (isReadStreamSource(source)) {
-        body = source.stream;
+
+      if (isFileSource(source)) {
+        body = source;
       } else {
         throw new DeepgramError("Unknown transcription source type");
       }
diff --git a/test/prerecorded.test.ts b/test/prerecorded.test.ts
index bf885704..df7aaa6e 100644
--- a/test/prerecorded.test.ts
+++ b/test/prerecorded.test.ts
@@ -3,12 +3,9 @@ import { createClient } from "../src";
 import { faker } from "@faker-js/faker";
 import DeepgramClient from "../src/DeepgramClient";
 import { CallbackUrl } from "../src/lib/helpers";
-import { BufferSource, UrlSource } from "../src/lib/types";
+import { UrlSource } from "../src/lib/types";
 
-const bufferSource: BufferSource = {
-  buffer: Buffer.from("string"),
-  mimetype: "video/mpeg",
-};
+const bufferSource: Buffer = Buffer.from("string");
 
 const urlSource: UrlSource = {
   url: faker.internet.url({ appendSlash: false }) + "/nasa.wav",