YouTube API JavaScript Guide

Use server-side JavaScript to fetch YouTube transcripts with the Scority API. Keep API keys out of browser code and handle transcript errors explicitly.

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Direct answer

Use JavaScript on the server, not in the browser

A YouTube transcript request needs an API key, so the request should run in trusted server-side JavaScript. Browser code can call your own backend route, but it should not call Scority directly with x-api-key.

Use fetch from a server runtime, route handler, worker or backend job.
Store SCORITY_API_KEY in server-side environment variables.
Send video_id or video_url, not both.
Use language when you need a specific caption language.

Server-side fetch by video ID

const apiKey = process.env.SCORITY_API_KEY

if (!apiKey) {
  throw new Error("SCORITY_API_KEY is required")
}

const url = new URL("https://api.scority.ai/v1/youtube/transcript")
url.searchParams.set("video_id", "dQw4w9WgXcQ")
url.searchParams.set("language", "en")

const response = await fetch(url, {
  headers: {
    "x-api-key": apiKey,
    accept: "application/json",
  },
})

const body = await response.json()

if (!response.ok) {
  throw new Error(body.error?.code ?? "transcript_request_failed")
}

Backend route wrapper

export async function POST(request: Request) {
  const { videoId } = await request.json()
  const url = new URL("https://api.scority.ai/v1/youtube/transcript")
  url.searchParams.set("video_id", videoId)

  const response = await fetch(url, {
    headers: {
      "x-api-key": process.env.SCORITY_API_KEY ?? "",
      accept: "application/json",
    },
  })

  return Response.json(await response.json(), {
    status: response.status,
  })
}

Request shape

Build the URL with query parameters

Use URL and URLSearchParams instead of string concatenation. It avoids encoding mistakes when you switch from video_id to video_url.

video_id is best when your app already stores the 11-character YouTube ID.
video_url is useful when users paste full YouTube links.
language and lang are aliases; use one.
The response includes text, segments, source and language when captions are available.

Errors