> ## Documentation Index > Fetch the complete documentation index at: https://docs.agentbody.io/llms.txt > Use this file to discover all available pages before exploring further. # Download YouTube video audio > Use this operation to save the audio of one public YouTube video as an audio file (MP3 by default; M4A, WAV, AAC, FLAC, OPUS, Vorbis, or ALAC) with a permanent retained download URL and normalized track metadata. Videos longer than roughly 25 minutes are rejected by the upstream cost guard. ## OpenAPI ````yaml /api-reference/openapi.json post /v1/youtube/audio/download openapi: 3.1.0 info: description: >- Direct authenticated APIs for public social data, people data, transcripts, documents, text, and SEO. Send an API key as a Bearer token. Responses never include provider credentials or raw provider payloads. license: name: Proprietary url: https://agentbody.io title: AgentBody API version: 2026-09-22.1 servers: - url: https://api.agentbody.io security: - bearerAuth: [] paths: /v1/youtube/audio/download: post: tags: - youtube summary: Download YouTube video audio description: >- Use this operation to save the audio of one public YouTube video as an audio file (MP3 by default; M4A, WAV, AAC, FLAC, OPUS, Vorbis, or ALAC) with a permanent retained download URL and normalized track metadata. Videos longer than roughly 25 minutes are rejected by the upstream cost guard. operationId: post_v1_youtube_audio_download parameters: - $ref: '#/components/parameters/IdempotencyKey' requestBody: content: application/json: schema: $ref: '#/components/schemas/YouTubeAudioDownloadRequest' required: true responses: '200': $ref: '#/components/responses/YouTubeAudioDownloadSuccess' '400': content: application/json: example: error: code: INVALID_ARGUMENT message: example error schema: additionalProperties: false properties: error: additionalProperties: false properties: code: const: INVALID_ARGUMENT type: string message: type: string required: - code - message type: object required: - error type: object description: Correct the input; do not retry unchanged. headers: X-Request-Id: description: Gateway request identifier for support and audit. schema: format: uuid type: string '401': content: application/json: example: error: code: UNAUTHENTICATED message: example error schema: additionalProperties: false properties: error: additionalProperties: false properties: code: const: UNAUTHENTICATED type: string message: type: string required: - code - message type: object required: - error type: object description: Configure a valid API key; do not retry unchanged. headers: X-Request-Id: description: Gateway request identifier for support and audit. schema: format: uuid type: string '409': content: application/json: example: error: code: CONFLICT message: example error schema: additionalProperties: false properties: error: additionalProperties: false properties: code: const: CONFLICT type: string message: type: string required: - code - message type: object required: - error type: object description: Follow the documented Idempotency-Key behavior before retrying. headers: X-Request-Id: description: Gateway request identifier for support and audit. schema: format: uuid type: string '502': content: application/json: example: error: code: UPSTREAM_INVALID_RESPONSE message: example error schema: additionalProperties: false properties: error: additionalProperties: false properties: code: const: UPSTREAM_INVALID_RESPONSE type: string message: type: string required: - code - message type: object required: - error type: object description: Retry with backoff, then report temporary unavailability. headers: X-Request-Id: description: Gateway request identifier for support and audit. schema: format: uuid type: string '503': content: application/json: example: error: code: UPSTREAM_UNAVAILABLE message: example error schema: additionalProperties: false properties: error: additionalProperties: false properties: code: const: UPSTREAM_UNAVAILABLE type: string message: type: string required: - code - message type: object required: - error type: object description: Retry with backoff, then report temporary unavailability. headers: X-Request-Id: description: Gateway request identifier for support and audit. schema: format: uuid type: string '504': content: application/json: example: error: code: UPSTREAM_TIMEOUT message: example error schema: additionalProperties: false properties: error: additionalProperties: false properties: code: const: UPSTREAM_TIMEOUT type: string message: type: string required: - code - message type: object required: - error type: object description: Retry with backoff, then report temporary unavailability. headers: X-Request-Id: description: Gateway request identifier for support and audit. schema: format: uuid type: string components: parameters: IdempotencyKey: description: Optional key for safely retrying a billable write request. example: request-20260819-001 in: header name: Idempotency-Key required: false schema: maxLength: 255 minLength: 1 type: string schemas: YouTubeAudioDownloadRequest: additionalProperties: false properties: bitrate: default: auto description: >- Audio bitrate preference. source keeps the original stream with no re-encode; specific bitrates transcode but never exceed the source. Ignored by lossless formats (wav/flac/alac). enum: - source - auto - 320k - 256k - 192k - 128k - 64k type: string format: default: mp3 description: Audio output format. enum: - mp3 - m4a - wav - aac - flac - opus - vorbis - alac type: string url: description: >- Public YouTube video URL (watch, Shorts, live, embed, or youtu.be link). Playlist URLs are not accepted. format: uri type: string required: - url type: object YouTubeAudioDownloadResult: additionalProperties: false properties: audio_url: format: uri type: string bitrate: type: string channel: type: string duration_seconds: type: number file_size_bytes: format: int64 type: integer format: type: string thumbnail_url: format: uri type: string title: type: string url: format: uri type: string video_id: type: string required: - video_id - url - audio_url - format type: object responses: YouTubeAudioDownloadSuccess: content: application/json: example: audio_url: https://example.com/audio-dQw4w9WgXcQ.mp3 bitrate: 192k channel: Example Channel duration_seconds: 212 file_size_bytes: 3407872 format: mp3 thumbnail_url: https://example.com/thumbnail-dQw4w9WgXcQ title: Example Track url: https://www.youtube.com/watch?v=dQw4w9WgXcQ video_id: dQw4w9WgXcQ schema: $ref: '#/components/schemas/YouTubeAudioDownloadResult' description: Retained audio file URL and normalized public track metadata. headers: X-Request-Id: description: Gateway request identifier for support and audit. schema: format: uuid type: string securitySchemes: bearerAuth: scheme: bearer type: http ````