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 21 Aug 2026

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 21 Aug 2026, 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.

Alternatives to SponsorBlock API

If SponsorBlock does not fit, these video & streaming apis cover similar ground. Every one was called before publishing, and each links to its own reference page with a working curl command and the response it returned.

API	What it does	Auth	CORS	Last verified
TVmaze	Free TV show API with no key: series info, full episode guides, cast, air dates and daily schedules with images. Genuinely open, no signup. Tested example.	No key	Yes	19 Aug 2026
Noembed	Free oEmbed proxy API with no key: get embed HTML, thumbnails and metadata for YouTube, Vimeo, Twitter and 200+ other sites from one endpoint. Tested.	No key	Yes	19 Aug 2026
IPTV-org	Free IPTV-org API with no key: 10,000+ TV channels worldwide with countries, languages, categories, logos and stream metadata as static JSON. Tested example.	No key	Yes	19 Aug 2026
YouTube oEmbed	Free YouTube oEmbed endpoint with no API key: video title, author, thumbnail and embed HTML from any video URL. No quota, unlike the Data API. Tested.	No key	No	20 Aug 2026
Stream.cz GraphQL	Stream.cz exposes a public, unauthenticated GraphQL API over its Czech video catalogue: shows, episodes, search and playout data, with introspection enabled. Live example included.	No key	No	21 Aug 2026
Stromberg API	A free, key-free API for the German sitcom Stromberg: quotes joined to the character who said them and the episode it came from, plus full cast and episode collections.	No key	Yes	21 Aug 2026

All Video & Streaming APIs

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