diff --git a/changes/fix-jellyfin-modern-auth.md b/changes/fix-jellyfin-modern-auth.md
new file mode 100644
index 00000000..4eb756a0
--- /dev/null
+++ b/changes/fix-jellyfin-modern-auth.md
@@ -0,0 +1,4 @@
+type: fixed
+area: jellyfin
+
+- Authenticate Jellyfin playback, subtitle, artwork, and remote-control socket URLs with the `ApiKey` query parameter and stop sending the legacy `X-Emby-Token` and `X-Emby-Authorization` headers, so the integration keeps working on Jellyfin 12 where legacy authorization is disabled by default.
diff --git a/docs-site/jellyfin-integration.md b/docs-site/jellyfin-integration.md
index 2d7704fd..b2f90e5a 100644
--- a/docs-site/jellyfin-integration.md
+++ b/docs-site/jellyfin-integration.md
@@ -12,7 +12,7 @@ This is the recommended way to use Jellyfin with SubMiner. A terminal-only optio
 
 ## Requirements
 
-- A Jellyfin server plus your username and password
+- A Jellyfin server plus your username and password (Jellyfin 12, which disables legacy authorization by default, is supported)
 - SubMiner installed and running (see [Installation](/installation))
 - On Linux, the session token is stored with `gnome-libsecret` by default
 
diff --git a/launcher/jellyfin.ts b/launcher/jellyfin.ts
index 742e4ffb..15cc1b26 100644
--- a/launcher/jellyfin.ts
+++ b/launcher/jellyfin.ts
@@ -89,7 +89,6 @@ export async function jellyfinApiRequest<T>(
   const url = `${session.serverUrl}${requestPath}`;
   const response = await fetch(url, {
     headers: {
-      'X-Emby-Token': session.accessToken,
       Authorization: `MediaBrowser Token="${session.accessToken}"`,
     },
   });
@@ -103,7 +102,7 @@ export async function jellyfinApiRequest<T>(
 }
 
 function itemPreviewUrl(session: JellyfinSessionConfig, id: string): string {
-  return `${session.serverUrl}/Items/${id}/Images/Primary?maxHeight=720&quality=85&api_key=${encodeURIComponent(session.accessToken)}`;
+  return `${session.serverUrl}/Items/${id}/Images/Primary?maxHeight=720&quality=85&ApiKey=${encodeURIComponent(session.accessToken)}`;
 }
 
 function jellyfinIconCacheDir(session: JellyfinSessionConfig): string {
diff --git a/launcher/picker.ts b/launcher/picker.ts
index 110a791a..98947048 100644
--- a/launcher/picker.ts
+++ b/launcher/picker.ts
@@ -228,7 +228,7 @@ export function pickLibrary(
     commandExists('chafa') && commandExists('curl')
       ? `
 id={1}
-url=${escapeShellSingle(session.serverUrl)}/Items/$id/Images/Primary?maxHeight=720\\&quality=85\\&api_key=${escapeShellSingle(session.accessToken)}
+url=${escapeShellSingle(session.serverUrl)}/Items/$id/Images/Primary?maxHeight=720\\&quality=85\\&ApiKey=${escapeShellSingle(session.accessToken)}
 curl -fsSL "$url" 2>/dev/null | chafa --format=symbols --symbols=vhalf+wide --size=${'${FZF_PREVIEW_COLUMNS}'}x${'${FZF_PREVIEW_LINES}'} - 2>/dev/null
 `.trim()
       : 'echo "Install curl + chafa for image preview"';
@@ -266,7 +266,7 @@ export function pickItem(
     commandExists('chafa') && commandExists('curl')
       ? `
 id={1}
-url=${escapeShellSingle(session.serverUrl)}/Items/$id/Images/Primary?maxHeight=720\\&quality=85\\&api_key=${escapeShellSingle(session.accessToken)}
+url=${escapeShellSingle(session.serverUrl)}/Items/$id/Images/Primary?maxHeight=720\\&quality=85\\&ApiKey=${escapeShellSingle(session.accessToken)}
 curl -fsSL "$url" 2>/dev/null | chafa --format=symbols --symbols=vhalf+wide --size=${'${FZF_PREVIEW_COLUMNS}'}x${'${FZF_PREVIEW_LINES}'} - 2>/dev/null
 `.trim()
       : 'echo "Install curl + chafa for image preview"';
@@ -304,7 +304,7 @@ export function pickGroup(
     commandExists('chafa') && commandExists('curl')
       ? `
 id={1}
-url=${escapeShellSingle(session.serverUrl)}/Items/$id/Images/Primary?maxHeight=720\\&quality=85\\&api_key=${escapeShellSingle(session.accessToken)}
+url=${escapeShellSingle(session.serverUrl)}/Items/$id/Images/Primary?maxHeight=720\\&quality=85\\&ApiKey=${escapeShellSingle(session.accessToken)}
 curl -fsSL "$url" 2>/dev/null | chafa --format=symbols --symbols=vhalf+wide --size=${'${FZF_PREVIEW_COLUMNS}'}x${'${FZF_PREVIEW_LINES}'} - 2>/dev/null
 `.trim()
       : 'echo "Install curl + chafa for image preview"';
diff --git a/src/anki-integration.test.ts b/src/anki-integration.test.ts
index 897e3897..4370446d 100644
--- a/src/anki-integration.test.ts
+++ b/src/anki-integration.test.ts
@@ -1545,3 +1545,25 @@ test('Anki metadata rejects a credential-bearing media title before metadata arr
   const result = privateApi.formatMiscInfoPattern('stream?api_key=test-secret', 426);
   assert.equal(result, '[SubMiner] Unknown media | Unknown media (00:07:06)');
 });
+
+test('AnkiIntegration.formatMiscInfoPattern treats ApiKey stream paths like legacy api_key ones', () => {
+  const integration = new AnkiIntegration(
+    { metadata: { pattern: '[SubMiner] %f (%t)' } } as never,
+    {} as never,
+    {
+      currentSubText: '',
+      currentVideoPath: 'stream?static=true&ApiKey=secret-token&MediaSourceId=ms-1',
+      currentTimePos: 426,
+      currentSubStart: 426,
+      currentSubEnd: 428,
+      currentMediaTitle: '[Jellyfin/direct] Bocchi the Rock! - S01E02',
+      send: () => true,
+    } as unknown as never,
+  );
+  const privateApi = integration as unknown as {
+    formatMiscInfoPattern: (fallbackFilename: string, startTimeSeconds?: number) => string;
+  };
+  const result = privateApi.formatMiscInfoPattern('audio_123.mp3', 426);
+  assert.equal(result, '[SubMiner] [Jellyfin/direct] Bocchi the Rock! - S01E02 (00:07:06)');
+  assert.equal(result.includes('ApiKey='), false);
+});
diff --git a/src/anki-integration.ts b/src/anki-integration.ts
index b2efb88c..eb1a3bd3 100644
--- a/src/anki-integration.ts
+++ b/src/anki-integration.ts
@@ -185,7 +185,7 @@ function extractFilenameFromMediaPath(rawPath: string): string {
 function shouldPreferMediaTitleForMiscInfo(rawPath: string, filename: string): boolean {
   const loweredPath = rawPath.toLowerCase();
   const loweredFilename = filename.toLowerCase();
-  if (loweredPath.includes('api_key=')) {
+  if (loweredPath.includes('api_key=') || loweredPath.includes('apikey=')) {
     return true;
   }
   if (loweredPath.startsWith('http://') || loweredPath.startsWith('https://')) {
diff --git a/src/core/services/immersion-tracker-service.test.ts b/src/core/services/immersion-tracker-service.test.ts
index 543ddb6e..dc432282 100644
--- a/src/core/services/immersion-tracker-service.test.ts
+++ b/src/core/services/immersion-tracker-service.test.ts
@@ -3174,6 +3174,7 @@ test('Jellyfin metadata cleanup requires both an API key and a stream marker', a
       { filename: 'stream?api_key=secret', leaked: true },
       { filename: '/STREAM?API_KEY=secret', leaked: true },
       { filename: '/Videos/item?api_key=secret', leaked: true },
+      { filename: '/Videos/item?ApiKey=secret', leaked: true },
       { filename: 'MediaSourceId=item api key secret', leaked: true },
       { filename: 'An API Key Story', leaked: false },
       { filename: 'api_key=ordinary-metadata', leaked: false },
diff --git a/src/core/services/immersion-tracker-service.ts b/src/core/services/immersion-tracker-service.ts
index 1cdc84d7..decde1fd 100644
--- a/src/core/services/immersion-tracker-service.ts
+++ b/src/core/services/immersion-tracker-service.ts
@@ -369,6 +369,7 @@ function buildJellyfinStatsMediaPath(mediaPath: string, itemId: string): string
 
 const JELLYFIN_MEDIA_ALIAS_QUERY_KEYS = [
   'api_key',
+  'ApiKey',
   'StartTimeTicks',
   'AudioStreamIndex',
   'SubtitleStreamIndex',
diff --git a/src/core/services/immersion-tracker/jellyfin-link-repair.ts b/src/core/services/immersion-tracker/jellyfin-link-repair.ts
index 4b499734..95d341c4 100644
--- a/src/core/services/immersion-tracker/jellyfin-link-repair.ts
+++ b/src/core/services/immersion-tracker/jellyfin-link-repair.ts
@@ -82,7 +82,7 @@ function parseLegacyJellyfinStreamUrl(value: string | null): URL | null {
     ) {
       return null;
     }
-    if (!url.searchParams.has('api_key')) {
+    if (!url.searchParams.has('api_key') && !url.searchParams.has('ApiKey')) {
       return null;
     }
     return url;
@@ -130,13 +130,13 @@ function repairLeakedJellyfinAnimeTitles(db: DatabaseSync, currentTimestamp: str
               SELECT v.canonical_title
               FROM imm_videos v
               WHERE v.anime_id = a.anime_id
-                AND v.canonical_title NOT LIKE '%api_key=%'
+                AND v.canonical_title NOT LIKE '%api_key=%' AND v.canonical_title NOT LIKE '%ApiKey=%'
                 AND lower(v.canonical_title) NOT LIKE '%api key%'
               ORDER BY v.LAST_UPDATE_DATE DESC, v.video_id DESC
               LIMIT 1
             ) AS linked_video_title
           FROM imm_anime a
-          WHERE a.canonical_title LIKE '%api_key=%'
+          WHERE a.canonical_title LIKE '%api_key=%' OR a.canonical_title LIKE '%ApiKey=%'
              OR lower(a.canonical_title) LIKE '%api key%'
              OR lower(a.normalized_title_key) LIKE '%api key%'
         `,
@@ -244,11 +244,11 @@ function repairLeakedJellyfinVideoParseMetadata(
           LAST_UPDATE_DATE = ?
         WHERE source_type = 2
           AND (
-            parsed_basename LIKE '%api_key=%'
+            parsed_basename LIKE '%api_key=%' OR parsed_basename LIKE '%ApiKey=%'
             OR lower(parsed_basename) LIKE '%api key%'
-            OR parsed_title LIKE '%api_key=%'
+            OR parsed_title LIKE '%api_key=%' OR parsed_title LIKE '%ApiKey=%'
             OR lower(parsed_title) LIKE '%api key%'
-            OR parse_metadata_json LIKE '%api_key=%'
+            OR parse_metadata_json LIKE '%api_key=%' OR parse_metadata_json LIKE '%ApiKey=%'
             OR lower(parse_metadata_json) LIKE '%api key%'
           )
       `,
@@ -267,7 +267,7 @@ function repairLeakedJellyfinAnimeParseMetadata(
     UPDATE imm_anime
     SET metadata_json = NULL, LAST_UPDATE_DATE = ?
     WHERE (
-      metadata_json LIKE '%api_key=%'
+      metadata_json LIKE '%api_key=%' OR metadata_json LIKE '%ApiKey=%'
       OR lower(metadata_json) LIKE '%api key%'
     ) AND (
       lower(metadata_json) LIKE '%stream?%'
@@ -295,11 +295,11 @@ export function repairJellyfinStreamVideoLinks(db: DatabaseSync): JellyfinLinkRe
         FROM imm_videos
         WHERE source_type = 2
           AND (
-            video_key LIKE '%api_key=%'
+            video_key LIKE '%api_key=%' OR video_key LIKE '%ApiKey=%'
             OR lower(video_key) LIKE '%api key%'
-            OR source_url LIKE '%api_key=%'
+            OR source_url LIKE '%api_key=%' OR source_url LIKE '%ApiKey=%'
             OR lower(source_url) LIKE '%api key%'
-            OR canonical_title LIKE '%api_key=%'
+            OR canonical_title LIKE '%api_key=%' OR canonical_title LIKE '%ApiKey=%'
             OR lower(canonical_title) LIKE '%api key%'
           )
       `,
diff --git a/src/core/services/jellyfin-remote.test.ts b/src/core/services/jellyfin-remote.test.ts
index 22b2e6b6..7877cadd 100644
--- a/src/core/services/jellyfin-remote.test.ts
+++ b/src/core/services/jellyfin-remote.test.ts
@@ -58,7 +58,7 @@ test('start posts capabilities on socket connect', async () => {
     accessToken: 'token-1',
     deviceId: 'device-1',
     webSocketFactory: (url) => {
-      assert.equal(url, 'ws://jellyfin.local:8096/socket?api_key=token-1&deviceId=device-1');
+      assert.equal(url, 'ws://jellyfin.local:8096/socket?ApiKey=token-1&deviceId=device-1');
       const socket = new FakeWebSocket();
       sockets.push(socket);
       return socket as unknown as any;
@@ -99,7 +99,8 @@ test('socket headers include jellyfin authorization metadata', () => {
   assert.equal(seenHeaders.length, 1);
   assert.ok(seenHeaders[0]!['Authorization']!.includes('Client="SubMiner"'));
   assert.ok(seenHeaders[0]!['Authorization']!.includes('DeviceId="device-auth"'));
-  assert.ok(seenHeaders[0]!['X-Emby-Authorization']);
+  assert.equal('X-Emby-Authorization' in seenHeaders[0]!, false);
+  assert.equal('X-Emby-Token' in seenHeaders[0]!, false);
 });
 
 test('dispatches inbound Play, Playstate, and GeneralCommand messages', () => {
diff --git a/src/core/services/jellyfin-remote.ts b/src/core/services/jellyfin-remote.ts
index ef0c301b..cd0ce605 100644
--- a/src/core/services/jellyfin-remote.ts
+++ b/src/core/services/jellyfin-remote.ts
@@ -342,7 +342,7 @@ export class JellyfinRemoteSessionService {
     const baseUrl = new URL(`${this.serverUrl}/`);
     const socketUrl = new URL('/socket', baseUrl);
     socketUrl.protocol = baseUrl.protocol === 'https:' ? 'wss:' : 'ws:';
-    socketUrl.searchParams.set('api_key', this.accessToken);
+    socketUrl.searchParams.set('ApiKey', this.accessToken);
     socketUrl.searchParams.set('deviceId', this.deviceId);
     return socketUrl.toString();
   }
@@ -350,8 +350,6 @@ export class JellyfinRemoteSessionService {
   private createSocket(url: string): JellyfinRemoteSocket {
     const headers: JellyfinRemoteSocketHeaders = {
       Authorization: this.authHeader,
-      'X-Emby-Authorization': this.authHeader,
-      'X-Emby-Token': this.accessToken,
     };
     if (this.socketHeadersFactory) {
       return this.socketHeadersFactory(url, headers);
@@ -375,8 +373,6 @@ export class JellyfinRemoteSessionService {
         method: 'GET',
         headers: {
           Authorization: this.authHeader,
-          'X-Emby-Authorization': this.authHeader,
-          'X-Emby-Token': this.accessToken,
         },
       });
       if (!response.ok) return false;
@@ -398,8 +394,6 @@ export class JellyfinRemoteSessionService {
         headers: {
           'Content-Type': 'application/json',
           Authorization: this.authHeader,
-          'X-Emby-Authorization': this.authHeader,
-          'X-Emby-Token': this.accessToken,
         },
         body: JSON.stringify(payload),
       });
diff --git a/src/core/services/jellyfin.test.ts b/src/core/services/jellyfin.test.ts
index 19e71a4d..c6340c29 100644
--- a/src/core/services/jellyfin.test.ts
+++ b/src/core/services/jellyfin.test.ts
@@ -279,7 +279,7 @@ test('resolvePlaybackPlan prefers transcode when directPlayPreferred is disabled
     assert.equal(plan.mode, 'transcode');
     const url = new URL(plan.url);
     assert.match(url.pathname, /\/Videos\/movie-2\/master\.m3u8$/);
-    assert.equal(url.searchParams.get('api_key'), 'token');
+    assert.equal(url.searchParams.get('ApiKey'), 'token');
     assert.equal(url.searchParams.get('AudioStreamIndex'), '4');
     assert.equal(url.searchParams.get('StartTimeTicks'), '10000000');
   } finally {
@@ -365,7 +365,7 @@ test('listSubtitleTracks returns all subtitle streams with delivery urls', async
                 IsForced: true,
                 IsExternal: true,
                 DeliveryMethod: 'External',
-                DeliveryUrl: '/Videos/movie-1/ms-1/Subtitles/3/Stream.srt',
+                DeliveryUrl: '/Videos/movie-1/ms-1/Subtitles/3/Stream.srt?api_key=server-token',
                 IsExternalUrl: false,
               },
               {
@@ -402,11 +402,11 @@ test('listSubtitleTracks returns all subtitle streams with delivery urls', async
     );
     assert.equal(
       tracks[0]!.deliveryUrl,
-      'http://jellyfin.local/Videos/movie-1/ms-1/Subtitles/2/Stream.srt?api_key=token',
+      'http://jellyfin.local/Videos/movie-1/ms-1/Subtitles/2/Stream.srt?ApiKey=token',
     );
     assert.equal(
       tracks[1]!.deliveryUrl,
-      'http://jellyfin.local/Videos/movie-1/ms-1/Subtitles/3/Stream.srt?api_key=token',
+      'http://jellyfin.local/Videos/movie-1/ms-1/Subtitles/3/Stream.srt?ApiKey=token',
     );
     assert.equal(tracks[2]!.deliveryUrl, 'https://cdn.example.com/subs.srt');
   } finally {
@@ -505,7 +505,7 @@ test('resolvePlaybackPlan reuses server transcoding url and appends missing para
     const url = new URL(plan.url);
     assert.match(url.pathname, /\/Videos\/movie-4\/master\.m3u8$/);
     assert.equal(url.searchParams.get('VideoCodec'), 'hevc');
-    assert.equal(url.searchParams.get('api_key'), 'token');
+    assert.equal(url.searchParams.get('ApiKey'), 'token');
     assert.equal(url.searchParams.get('AudioStreamIndex'), '3');
     assert.equal(url.searchParams.get('SubtitleStreamIndex'), '8');
     assert.equal(url.searchParams.get('StartTimeTicks'), '50000000');
@@ -626,7 +626,7 @@ test('listSubtitleTracks falls back from PlaybackInfo to item media sources', as
     assert.equal(tracks[0]!.index, 11);
     assert.equal(
       tracks[0]!.deliveryUrl,
-      'http://jellyfin.local/Videos/movie-fallback/ms-fallback/Subtitles/11/Stream.srt?api_key=token',
+      'http://jellyfin.local/Videos/movie-fallback/ms-fallback/Subtitles/11/Stream.srt?ApiKey=token',
     );
   } finally {
     globalThis.fetch = originalFetch;
@@ -789,3 +789,67 @@ test('resolvePlaybackPlan surfaces no-source and no-stream fallback errors', asy
     globalThis.fetch = originalFetch;
   }
 });
+
+test('API requests authenticate with the MediaBrowser header only (no legacy X-Emby-Token)', async () => {
+  const originalFetch = globalThis.fetch;
+  const seenHeaders: Headers[] = [];
+  globalThis.fetch = (async (_input, init) => {
+    seenHeaders.push(new Headers(init?.headers));
+    return new Response(JSON.stringify({ Items: [] }), { status: 200 });
+  }) as typeof fetch;
+
+  try {
+    await listLibraries(
+      { serverUrl: 'http://jellyfin.local', accessToken: 'token', userId: 'u1', username: 'kyle' },
+      clientInfo,
+    );
+    assert.equal(seenHeaders.length, 1);
+    const headers = seenHeaders[0]!;
+    const authorization = headers.get('authorization') ?? '';
+    assert.match(authorization, /^MediaBrowser /);
+    assert.match(authorization, /Token="token"/);
+    assert.match(authorization, /DeviceId="subminer-test"/);
+    assert.equal(headers.has('x-emby-token'), false);
+    assert.equal(headers.has('x-emby-authorization'), false);
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test('resolvePlaybackPlan replaces a legacy api_key on the server transcoding url with ApiKey', async () => {
+  const originalFetch = globalThis.fetch;
+  globalThis.fetch = (async () =>
+    new Response(
+      JSON.stringify({
+        Id: 'movie-legacy',
+        Name: 'Movie Legacy',
+        MediaSources: [
+          {
+            Id: 'ms-legacy',
+            Container: 'mkv',
+            SupportsDirectStream: false,
+            SupportsTranscoding: true,
+            TranscodingUrl: '/Videos/movie-legacy/master.m3u8?VideoCodec=hevc&api_key=server-token',
+          },
+        ],
+      }),
+      { status: 200 },
+    )) as typeof fetch;
+
+  try {
+    const plan = await resolvePlaybackPlan(
+      { serverUrl: 'http://jellyfin.local', accessToken: 'token', userId: 'u1', username: 'kyle' },
+      clientInfo,
+      { enabled: true, directPlayPreferred: true },
+      { itemId: 'movie-legacy' },
+    );
+
+    assert.equal(plan.mode, 'transcode');
+    const url = new URL(plan.url);
+    assert.equal(url.searchParams.get('ApiKey'), 'token');
+    assert.equal(url.searchParams.has('api_key'), false);
+    assert.equal(url.searchParams.get('VideoCodec'), 'hevc');
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
diff --git a/src/core/services/jellyfin.ts b/src/core/services/jellyfin.ts
index a09577e6..e960604c 100644
--- a/src/core/services/jellyfin.ts
+++ b/src/core/services/jellyfin.ts
@@ -136,6 +136,16 @@ function getErrorMessage(error: unknown): string {
   return String(error || 'unknown error');
 }
 
+// Jellyfin reads query keys case-insensitively and older servers embed the token as
+// `api_key` in the URLs they hand back, so drop every spelling before setting the one
+// form Jellyfin 12 still accepts with legacy authorization disabled.
+function setApiKeyParam(url: URL, accessToken: string): void {
+  for (const key of [...url.searchParams.keys()]) {
+    if (/^api_?key$/i.test(key)) url.searchParams.delete(key);
+  }
+  url.searchParams.set('ApiKey', accessToken);
+}
+
 function resolveDeliveryUrl(
   session: JellyfinAuthSession,
   stream: JellyfinMediaStream,
@@ -146,9 +156,7 @@ function resolveDeliveryUrl(
   if (deliveryUrl) {
     if (stream.IsExternalUrl === true) return deliveryUrl;
     const resolved = new URL(deliveryUrl, `${session.serverUrl}/`);
-    if (!resolved.searchParams.has('api_key')) {
-      resolved.searchParams.set('api_key', session.accessToken);
-    }
+    setApiKeyParam(resolved, session.accessToken);
     return resolved.toString();
   }
 
@@ -171,9 +179,7 @@ function resolveDeliveryUrl(
     `/Videos/${encodeURIComponent(itemId)}/${encodeURIComponent(mediaSourceId)}/Subtitles/${streamIndex}/Stream.${ext}`,
     `${session.serverUrl}/`,
   );
-  if (!fallback.searchParams.has('api_key')) {
-    fallback.searchParams.set('api_key', session.accessToken);
-  }
+  setApiKeyParam(fallback, session.accessToken);
   return fallback.toString();
 }
 
@@ -197,7 +203,6 @@ async function jellyfinRequestJson<T>(
   const headers = new Headers(init.headers ?? {});
   headers.set('Content-Type', 'application/json');
   headers.set('Authorization', createAuthorizationHeader(client, session.accessToken));
-  headers.set('X-Emby-Token', session.accessToken);
 
   const response = await fetch(`${session.serverUrl}${path}`, {
     ...init,
@@ -221,7 +226,7 @@ function createDirectPlayUrl(
 ): string {
   const query = new URLSearchParams({
     static: 'true',
-    api_key: session.accessToken,
+    ApiKey: session.accessToken,
     MediaSourceId: ensureString(mediaSource.Id),
   });
   if (mediaSource.LiveStreamId) {
@@ -245,9 +250,7 @@ function createTranscodeUrl(
 ): string {
   if (mediaSource.TranscodingUrl) {
     const url = new URL(`${session.serverUrl}${mediaSource.TranscodingUrl}`);
-    if (!url.searchParams.has('api_key')) {
-      url.searchParams.set('api_key', session.accessToken);
-    }
+    setApiKeyParam(url, session.accessToken);
     if (!url.searchParams.has('AudioStreamIndex') && plan.audioStreamIndex !== null) {
       url.searchParams.set('AudioStreamIndex', String(plan.audioStreamIndex));
     }
@@ -261,7 +264,7 @@ function createTranscodeUrl(
   }
 
   const query = new URLSearchParams({
-    api_key: session.accessToken,
+    ApiKey: session.accessToken,
     MediaSourceId: ensureString(mediaSource.Id),
     VideoCodec: ensureString(config.transcodeVideoCodec, 'h264'),
     TranscodingContainer: 'ts',