SponsorBlock API

SponsorBlock's public API returns crowdsourced sponsor, intro and self-promo timestamps for YouTube videos, with a privacy-preserving hash-prefix lookup. Live example included.

No API key requiredCORS enabledHTTPSFree tier

Endpoint tested and returned HTTP 200 on 2026-08-21

What is the SponsorBlock API?

SponsorBlock is a free, key-free API serving crowdsourced timestamps that mark sponsored segments, intros, outros, self-promotion and other skippable sections of YouTube videos. Lookups can be made by video id or, for privacy, by the first few characters of the video id's SHA-256 hash.

The hash-prefix lookup is the design decision worth studying even if you never use the data. Asking `GET /api/skipSegments?videoID=abc123` tells the server exactly which video your user is watching. Asking `GET /api/skipSegments/aaaa` — the first four hex characters of the SHA-256 of the video id — returns segments for every video whose hash starts that way, typically a few dozen, and you match the one you want locally. The server learns almost nothing. It is k-anonymity applied to a video API, the same technique Have I Been Pwned uses for password lookups, and it costs you one extra hash and a small over-fetch.

The dataset itself is substantial and entirely community-submitted: millions of segments across YouTube, each with a category, a start and end time in seconds, a vote count and a `locked` flag showing whether a moderator has pinned it. Because it is crowdsourced, quality varies and votes matter — a segment on two votes is a suggestion, one that is locked is settled. The same server also hosts DeArrow, which crowdsources less clickbaity titles and thumbnails through `/api/branding`, so one integration covers both.

Quick facts

Base URL: https://sponsor.ajay.app
Authentication: No key for reads. Submitting or voting on segments requires a locally generated user id, which is a write path and outside the scope of this page.
Rate limit: No published limit, but the project runs on donations. Use the hash-prefix endpoint and cache — it is cheaper for both sides.
Pricing: Free and open source, database licensed for reuse with attribution.
CORS: Enabled — callable directly from browser JavaScript
Official docs: Read the docs

How to use the SponsorBlock API

Every request below was executed against the live API on 2026-08-21, and the response shown is the real body it returned — not an illustration.

1. Fetch segments by SHA-256 hash prefix (privacy-preserving)

GET https://sponsor.ajay.app/api/skipSegments/aaaa

curl

curl 'https://sponsor.ajay.app/api/skipSegments/aaaa'

JavaScript (fetch)

const res = await fetch("https://sponsor.ajay.app/api/skipSegments/aaaa");
if (!res.ok) throw new Error(`Request failed: ${res.status}`);
const data = await res.json();
console.log(data);

Python (requests)

import requests

res = requests.get("https://sponsor.ajay.app/api/skipSegments/aaaa", timeout=20)
res.raise_for_status()
print(res.json())

Response — HTTP 200 (truncated)

[
  {
    "videoID": "EC3rcN0JBS0",
    "segments": [
      {
        "category": "sponsor",
        "actionType": "skip",
        "segment": [
          0,
          103.054
        ],
        "UUID": "49c2c363ec44052654e9a26fa55b062ee7d8cbe500baf008ecec4d1305b597fb7",
        "videoDuration": 1718,
        "locked": 0,
        "votes": 2,
        "description": ""
      }
    ]
  },
  {
    "videoID": "yS3KbqttD7U",
    "segments": [
      {
        "category": "sponsor",
        "actionType": "skip",
        "segment": [
          0,
          9.816
        ],
        "UUID": "aa00494238306addc983719abc123121c375e6c10cd9522fc9ccff3b52b3b9b06",
        "videoDuration": 655,
        "locked": 0,
        "votes": 0,
        "description": ""
      }
    ]
  },
  {
    "videoID": "I9O2SKdljhc",
    "segments": [
      {
        "category": "sponsor",
        "actionType": "skip",
        "segment": [
          0,
          25
        ],
        "UUID": "0191806b81cf6a0b050c1060a044d0fdcc897c5e87d04c7b02deb569b8786b88",
        "videoDuration": 0,
        "locked": 0,
        "votes": 0,
        "description": ""
      }
    ]
  },
  {
    "videoID": "5c9S0YzVqbM",
    "segments": [
      {
        "category": "sponsor",
        "actionType": "skip",
        "segment": [
          0,
          14.414
        ],
        "UUID": "2e0f4ca54427e4c6fab87bbd4d616e0f44b90c1513581f5608d04c2dd55645f57",
        "videoDuration": 1090,
        "locked": 0,
        "votes": 0,
        "description": ""
      }
    ]
  },
  {
    "videoID": "gQc9hydTVak",
    "segments": [
      {

2. Fetch crowdsourced titles and thumbnails via DeArrow

GET https://sponsor.ajay.app/api/branding?videoID=jNQXAC9IVRw

curl

curl 'https://sponsor.ajay.app/api/branding?videoID=jNQXAC9IVRw'

JavaScript (fetch)

const res = await fetch("https://sponsor.ajay.app/api/branding?videoID=jNQXAC9IVRw");
if (!res.ok) throw new Error(`Request failed: ${res.status}`);
const data = await res.json();
console.log(data);

Python (requests)

import requests

res = requests.get("https://sponsor.ajay.app/api/branding?videoID=jNQXAC9IVRw", timeout=20)
res.raise_for_status()
print(res.json())

Response — HTTP 200

{
  "titles": [
    {
      "title": "Me at the zoo",
      "original": true,
      "votes": 10,
      "locked": true,
      "UUID": "c1f72c2a-1237-4f72-9cb1-8e5cf542aadb"
    },
    {
      "title": "Visiting the San Diego Zoo, talking about elephants",
      "original": false,
      "votes": 3,
      "locked": false,
      "UUID": "5eb7581d-3f73-4038-8fcf-a88faf970657"
    },
    {
      "title": "Me at the zoo (oldest YouTube video)",
      "original": false,
      "votes": 0,
      "locked": false,
      "UUID": "68a0dbc9-c859-46ad-bf2a-ec5145990883"
    }
  ],
  "thumbnails": [
    {
      "timestamp": null,
      "original": true,
      "votes": 3,
      "locked": false,
      "UUID": "47d9b22e-8624-41a0-ba1b-8f49861c6617"
    },
    {
      "timestamp": 0,
      "original": false,
      "votes": 0,
      "locked": false,
      "UUID": "d71d9919-a1d2-456f-8fac-139a5aed999b"
    },
    {
      "timestamp": 10.780416,
      "original": false,
      "votes": 0,
      "locked": false,
      "UUID": "dfe9fc2b-a304-4f65-88e5-259f26046471"
    }
  ],
  "casualVotes": [
    {
      "id": "descriptive",
      "count": 1,
      "title": "me at the zoo"
    }
  ],
  "randomTime": 0.8537647312041372,
  "videoDuration": null
}

Parameters

Parameter	Type	Required	Description
`hashPrefix`	path segment	Optional	First 4 to 32 hex characters of the SHA-256 of the video id. Returns every matching video's segments so the server never learns which one you wanted. `aaaa`
`videoID`	string	Optional	Direct lookup on `/api/skipSegments?videoID=` or `/api/branding?videoID=`. Simpler, but reveals the video to the server. `jNQXAC9IVRw`
`categories`	JSON array	Optional	Which segment types to return, as a JSON-encoded array. `["sponsor","intro"]`
`actionTypes`	JSON array	Optional	Filter by action: `skip`, `mute`, `full` or `poi`. `["skip"]`

Response fields

[].videoIDstring: The YouTube video id. Present on hash-prefix responses so you can match locally.
[].segments[].categorystring: `sponsor`, `selfpromo`, `interaction`, `intro`, `outro`, `preview`, `music_offtopic` or `filler`.
[].segments[].actionTypestring: What a player should do: `skip`, `mute`, `full` (whole video) or `poi` (a point of interest).
[].segments[].segmentarray of two floats: Start and end time in seconds. Floats, not integers — do not round before seeking.
[].segments[].votesinteger: Community vote score. Low or negative scores signal a disputed segment.
[].segments[].lockedinteger: 1 when a moderator has locked the segment as correct. Trust these over unlocked ones.
[].segments[].videoDurationfloat: Video length in seconds at submission time — useful for detecting re-uploads where timestamps no longer apply.
[].segments[].UUIDstring: Unique segment id, needed if you later vote on it.

What you can build with the SponsorBlock API

Add sponsor skipping to a custom video player or embed
Analyse how much of a channel's runtime is sponsored content
Build a browser extension or media-centre plugin without your own dataset
Study k-anonymity in practice as a privacy-engineering example
Pull crowdsourced non-clickbait titles and thumbnails through the DeArrow branding endpoint

Common errors and how to fix them

404 on a videoID lookup

Nobody has submitted segments for that video.

Fix: This is the normal case for most videos, not an error. Treat 404 as 'no segments' and carry on.

Hash prefix returns unrelated videos

That is the design.

Fix: A short prefix matches many video ids. Hash the id you care about yourself and filter the response locally.

Timestamps do not line up

The video was re-uploaded or edited after the segments were submitted.

Fix: Compare the returned `videoDuration` against the actual video and discard segments where they disagree.

Bad segments in the results

Anyone can submit; not everything is accurate.

Fix: Weight by `votes` and prefer `locked` segments. Filtering out anything below a vote threshold removes most of the noise.

SponsorBlock API — frequently asked questions

Is the SponsorBlock API free to use?

Yes. Reading segments needs no key or account, and the database is licensed for reuse with attribution. Submitting segments is a separate write path that requires a locally generated user id.

How does the privacy-preserving lookup work?

You hash the video id with SHA-256 and send only the first few hex characters as a path segment. The server returns segments for every video whose hash shares that prefix, and you pick out the one you wanted locally — so the server never learns which video you were watching.

What do the segment categories mean?

`sponsor` is paid promotion, `selfpromo` is the creator promoting their own merchandise or Patreon, `intro` and `outro` are title and end cards, `interaction` is 'like and subscribe' reminders, `preview` is a recap, `music_offtopic` marks non-music sections of music videos, and `filler` is tangential content.

Can I trust every segment?

Not blindly. It is crowdsourced, so weight by the `votes` field and prefer segments with `locked` set to 1, which means a moderator has confirmed them. A segment with two votes and no lock is a suggestion.

Tools that pair with this API

YouTube Chapter Timestamp Generator

Build a YouTube chapter list from titles and durations — start times are added up for you and checked against YouTube's chapter rules before you copy.

YouTube Embed Code Generator

Generate a YouTube iframe embed with start and end times, autoplay, loop, privacy-enhanced mode and a responsive aspect-ratio wrapper for any page.

Time Duration Calculator

Add or subtract hours, minutes and seconds, or sum a list of durations into a total shown in h:m:s and in total seconds. Free and 100% in-browser.

SponsorBlock is an independent third-party service and is not affiliated with ByteTools or ByteVancer. Details on this page were verified on 2026-08-21; always check the official documentation before relying on this API in production, as terms and limits can change.