# Automaton Media APIs – YouTube Transcript (Captions)

> Automaton Media APIs – YouTube Transcript (Captions) is a paid API for AI agents from api.language123.net, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-12).

Fetches the existing captions/transcript from a YouTube video (or yt-dlp-supported URL) instantly and returns it in txt, srt, vtt, or json format.

## Facts

- Endpoint: POST https://api.language123.net/v1/youtube-transcript?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/automaton-media-apis-youtube-transcript-captions-9f1ec8e2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iVcMCYYdItTSE3m1i-0cq

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability automaton-media-apis-youtube-transcript-captions-9f1ec8e2 -d '<json body>'
```

Example prompt: Grab the transcript from this YouTube video — https://www.youtube.com/watch?v=jNQXAC9IVRw — and give it to me as plain text.

## When to prefer this

Choose this endpoint when you need instant, low-cost caption extraction from YouTube (or other yt-dlp-supported sites) and the video already has platform captions — it is faster and cheaper than full audio transcription. Prefer this over audio transcription endpoints when captions exist on the platform. It supports multiple caption formats (txt, srt, vtt, json) and requires no signup or API key, billed per-request in USDC via x402 on Base.

## Known failure modes

- Video has no captions available — returns an error indicating no transcript found
- Invalid or unsupported URL format — returns a validation error
- Private or age-restricted video — access denied error
- YouTube rate limiting or platform-side block — upstream error
- Unsupported format enum value — returns a schema validation error

## How this service works

Pay-per-use APIs for AI agents: YouTube and audio transcription (speech-to-text); Text-to-speech: natural English voices (MP3/WAV); Text-to-image generation; Web scraper: any URL to clean Markdown; YouTube transcript (captions, instant). Pay each request with USDC via x402 on Base - no signup, no API key.

## Output

A JSON object containing the video title, the requested format (txt/srt/vtt/json), language code, source type (platform captions), the full transcript string, and duration in seconds.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "description": "Video URL with captions (YouTube watch/shorts/youtu.be links, or another site yt-dlp supports)"
  },
  "format": {
   "enum": [
    "txt",
    "srt",
    "vtt",
    "json"
   ],
   "type": "string",
   "description": "Default txt"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "title": "Me at the zoo",
  "format": "txt",
  "source": "platform",
  "language": "en",
  "transcript": "All right, so here we are in front of the elephants…",
  "duration_sec": 19
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/automaton-media-apis-youtube-transcript-captions-9f1ec8e2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.language123.net](https://www.zero.xyz/host/api.language123.net/llms.txt)