YouTube
GET /v1/youtube/summarize

YouTube Summarizer API

AI summary from YouTube's published captions — same source as /transcript. Flat 3 credits; caption-miss 404 is free.

3 credits per request
TL;DR
AI summary from YouTube's published captions — same source as /transcript. Flat 3 credits; caption-miss 404 is free. The YouTube Summarizer API (YouTube) is a single authenticated GET request to /v1/youtube/summarize that responds with clean JSON and costs 3 credits. Pass cache=true for a free 24h cache hit; default is always fresh. Start with 100 free credits — no credit card.

What is the YouTube Summarizer API?

Fetches YouTube's published captions (same engine as /transcript — not speech-to-text) and returns an AI summary, key points, topics, and sentiment. When the video has no caption tracks, you get the same diagnostic 404 as /transcript (code, reason, availableLanguages, hasAutoCaptions) and are charged 0 credits — never 3. Long live streams often lack auto-captions. Flat 3 credits only when a summary is returned.

What you get

  • 2–3 paragraph AI summary
  • 4–8 bullet key points and detected topics
  • Overall sentiment and tone
  • Built on the transcript under the hood

Try it

Open in Playground

Fill in the parameters below and copy a ready-to-run request, or open the live Playground to run it against your account (no API key paste).

Parameters

Sign in to run live
curl "https://api.captapi.com/v1/youtube/summarize?url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DiG9CE55wbtY" \
  -H "Authorization: Bearer capt_live_..."
# or: -H "x-api-key: capt_live_..."

Edit the parameters and the code updates instantly. Switch languages and hit copy.

Example response

{
  "success": true,
  "data": {
    "url": "https://www.youtube.com/watch?v=iG9CE55wbtY",
    "videoId": "iG9CE55wbtY",
    "title": "Do schools kill creativity? | Sir Ken Robinson | TED",
    "summary": "In his TED talk, Sir Ken Robinson explores the critical role of creativity in education and argues that the current education system stifles this essential human capacity. He highlights the extraordinary creativity present in children and contends that, as they grow, they become increasingly fearful of making mistakes, which ultimately hinders their ability to innovate. Robinson emphasizes that creativity should be valued as highly as literacy in educational curricula, as it is vital for preparing students for an unpredictable future. He illustrates his points with anecdotes about children’s natural creativity and the detrimental effects of a rigid educational hierarchy that prioritizes academic subjects over the arts.\n\nRobinson also critiques the traditional education system for its focus on producing university professors rather than nurturing diverse talents. He calls for a rethinking of intelligence that recognizes its dynamic and distinct nature, advocating for an educational approach that embraces creativity and allows children to explore their full potential. By fostering an e …",
    "keyPoints": [
      "Creativity is as important as literacy in education and should be treated with equal status.",
      "Children are naturally creative but often lose this ability as they grow due to fear of making mistakes.",
      "The education system prioritizes academic subjects over the arts, which limits the development of diverse talents.",
      "Intelligence is dynamic and should be understood as a combination of various ways of thinking and learning.",
      "Mistakes should be embraced in educational settings to foster creativity and innovation.",
      "A new conception of human ecology is needed to appreciate and nurture human capacities.",
      "The future of education must focus on the holistic development of children to prepare them for an unpredictable world."
    ],
    "topics": [
      "Creativity",
      "Education",
      "Intelligence",
      "Child Development",
      "Arts in Education",
      "Mistakes in Learning",
      "Future of Education"
    ],
    "sentiment": "positive"
  }
}

Billing metadata is returned in response headers: X-Captapi-Credits (credits charged), X-Captapi-Cache (hit or miss), and X-Captapi-Request-Id (include it when contacting support). Where the response has a source field, it names the path that served the data: native, extended, cache or asr. Failed requests (4xx/5xx) are never charged. See the full list of error codes in the error reference.

Response structure

A successful call returns success and a data object with the following fields:

Top-level fields

  • urlCanonical URL of the item.
  • videoIdPlatform video ID.
  • titleTitle of the item.
  • summaryAI-generated summary of the content.
  • keyPointsThe most important takeaways.
  • topicsDetected topics and themes.
  • sentimentOverall tone (positive, neutral, negative).

Parameters

NameTypeRequiredDescription
urlstringYesPublic YouTube video URL, e.g. https://youtube.com/watch?v=ID. Not a TikTok/Instagram/Facebook URL. The URL platform must match this endpoint's platform. Do not pass cross-platform URLs, e.g. YouTube to TikTok, Instagram to Facebook, LinkedIn to X/Twitter, or Pinterest to Rumble.
languagestringNoPreferred caption language as an ISO code, e.g. "en". Defaults to auto-detect.
cachebooleanNoSet true to serve from the 24h response cache (0 credits on hit). Default false — always fetch fresh.

Authentication: send your key as Authorization: Bearer capt_live_.... A typical call costs 3 credits. Pass cache=true for a free 24h cache hit; default is always fresh.

Using an AI agent? This endpoint is the MCP tool youtube_summarize via @captapi/mcp. Set it up →

How it works

  1. 1. Sign up — get 100 free credits, no card required.
  2. 2. Create a key from your dashboard.
  3. 3. Send one request to /v1/youtube/summarize and parse the JSON response.

Use cases

Content Triage

Decide what's worth watching without watching it.

Newsletters & Digests

Auto-generate summaries for roundups and emails.

Research

Condense long videos into key points at scale.

SEO

Generate descriptions and meta content from videos.

Social

Draft captions and posts from video content.

Frequently asked questions

What does the YouTube Summarizer API do?+

The YouTube Summarizer API lets you generate an AI summary with key points and topics from a public YouTube video using one GET request to /v1/youtube/summarize. It returns clean JSON — no OAuth or infrastructure setup required.

How many credits does the YouTube Summarizer API cost?+

Each successful call costs 3 credits. Pass cache=true to serve from the 24h cache (0 credits on hit); default is always fresh. Selected profile endpoints also accept cacheMaxAge=1d|3d|7d|14d|30d. Failed or empty results are never charged.

Do I need a YouTube API key or OAuth?+

No. A single Captapi key works across every platform Captapi supports — YouTube, TikTok, Instagram, Facebook, Twitter/X, Reddit, Threads, Bluesky, Pinterest, LinkedIn, Rumble, Spotify, Kwai, and more. We handle access, rate limits, retries, and authentication for you.

Which AI model powers the summaries?+

Summaries are generated by an AI model from the transcript.

Why did I get 404 on a video with clear speech?+

This endpoint returns captions YouTube published — it does not run speech-to-text. Read detail.code: no_captions means the video is playable but tracks=0 (common on long live streams); language_not_available means tracks exist but not in your language (see availableLanguages); video_unavailable means the video is deleted, private, or otherwise unplayable (YouTube: "this video is no longer available"). On no_captions only, detail.suggestion points at /v1/youtube/audio-transcript with estimatedCredits. 404 never charges credits.

If I pass language=en and only Turkish captions exist, what happens?+

We try YouTube's timedtext translation into en. If that fails → 404 language_not_available with availableLanguages (not a silent Turkish transcript). On success, requestedLanguage and returnedLanguage are both set; isTranslated is true when YouTube translated.

Is the YouTube Summarizer API suitable for production use?+

Yes. It is a stable REST endpoint with predictable JSON and automatic retries. Pass cache=true to serve from the 24h cache (0 credits on hit); default is always fresh. Selected profile endpoints also accept cacheMaxAge=1d|3d|7d|14d|30d. Use it for analytics, monitoring, and content automation.

More YouTube APIs

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YouTube Summarizer API — Captapi