---
title: "YouTube Summarizer API"
method: GET
path: "/v1/youtube/summarize"
tags: ["YouTube"]
---

# YouTube Summarizer API

`GET /v1/youtube/summarize`

## Request

- Base URL: `https://api.captapi.com`
- URL: `https://api.captapi.com/v1/youtube/summarize`
- Auth: one of:
  - HTTP bearer
  - API key in header `X-API-Key`

AI summary from YouTube's published captions — same source as /transcript.

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.

Docs: https://captapi.com/apis/youtube-summarizer

## Query parameters

- `url` string, required
- `language` string
- `cache` boolean

## Response `200`

Success. The data object for this endpoint.

- object
  - `success` unknown, required
  - `data` object, required
    - `url` string: Canonical URL of the item.
    - `videoId` string: Platform video ID.
    - `title` string: Title of the item.
    - `summary` string: AI-generated summary of the content.
    - `keyPoints` string[]: The most important takeaways.
    - `topics` string[]: Detected topics and themes.
    - `sentiment` string: Overall tone (positive, neutral, negative).

## Other responses

- `400`: Bad request: wrong platform URL, unknown endpoint, or an invalid parameter value. Not billed.
- `401`: Missing, invalid or revoked API key. Not billed.
- `402`: Not enough credits for this request. Not billed.
- `404`: The resource does not exist or is not public. Not billed.
- `422`: A required parameter is missing or has the wrong type. Not billed.
- `429`: Rate limit reached. Wait for Retry-After seconds. Not billed.
- `502`: The platform could not be reached or returned nothing usable. Retryable, not billed. 503 and 504 use the same envelope.

---

[API](https://skmtc.dev/captapi/apis/captapi-api.md) · [All operations](https://skmtc.dev/captapi/apis/captapi-api/llms.txt) · [OpenAPI document](https://skmtc.dev/captapi/apis/captapi-api/revisions/c9b9ac5ff1bd?raw)