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SponsorBlock is a free, open-source browser extension where viewers submit the exact start and end timestamps of a video's sponsored segment, which the extension then automatically skips for every other user who has it installed. The "Sponsor" category is skipped by default with zero action from the viewer — as of 26 August 2026, the Chrome Web Store and Firefox Add-ons listings show over 2,000,000 and 747,487 users respectively. It only targets content embedded inside the video file itself — a paid influencer integration — not YouTube's own inserted ads, which ordinary ad blockers handle instead.
SponsorBlock is a free, open-source browser extension and API that lets ordinary viewers mark the exact start and end timestamps of a sponsored segment inside a YouTube video. Submitted timestamps go into a shared, crowdsourced database that the extension checks in real time on every playback — and if a segment is already known, it's skipped automatically for anyone else running the extension, with zero action required from them. That makes SponsorBlock fundamentally different from an ad blocker: it doesn't touch YouTube's own inserted ads, it targets the content a creator has themselves placed inside the video — including exactly the kind of paid mention a brand typically pays for in an influencer deal.
SponsorBlock was built by Ajay Ramachandran and is open source, available as a browser extension for Chrome, Firefox and several other browsers, plus an open API, per the project's own GitHub repository. It's built specifically for YouTube — this article's research found no comparable crowdsourced segment-skip tool with similar reach built for TikTok or Instagram. Beyond the browser extension, SponsorBlock is also built into ReVanced, a popular patched version of YouTube's own Android app, meaning the tool's real-world reach extends beyond the install counts the browser stores themselves report — there's no published figure for how large that additional layer is, so it isn't counted in the numbers below.
The mechanic is pure crowdsourcing: a viewer who spots a sponsored segment submits its start and end timestamp through the extension's own interface and tags it with a category. Other users' playback is checked continuously against the database — for privacy, only a hashed prefix of the video ID is sent to the server, not the ID itself, per the project's own documentation. Incorrect or malicious submissions can be downvoted by other users, and users with a track record of reliable submissions earn a higher reputation score.
The project's own wiki and independent reviews of it list around a dozen categories, the ones most relevant to a paid placement being:
The practical point, and the one that matters most to a brand: the Sponsor category is skipped automatically by default, with no click required from the viewer at all — per the project's own documentation and independent reviews of the default setup. Other, less clear-cut categories instead surface an optional "skip" button. That means a paid integration can genuinely be removed from a viewer's experience entirely automatically, the moment enough other users have flagged that exact time range.
Direct, live lookups performed for this article on 26 August 2026 show the following, pulled straight from the two largest browser stores' own listings — not from SponsorBlock's own stats dashboard, which couldn't be loaded without JavaScript:
| Source | User count | Rating |
|---|---|---|
| Chrome Web Store | 2,000,000 users (Google's own rounded display) | 4.6 stars (~3.5K ratings) |
| Firefox Add-ons (Mozilla) | 747,487 users | 4.8 stars (3,186 reviews) |
These figures are the stores' own install counts, not SponsorBlock's own project stats panel — the Chrome Web Store typically shows a rounded, bucketed figure rather than a precise count. Added together, and without being able to quantify the extra ReVanced layer, that represents somewhere between 2.5 and 3 million active installs of a tool whose sole purpose is to skip exactly the kind of content a brand is paying for.
It's essential to keep SponsorBlock separate from ordinary ad blockers like uBlock Origin, already covered in the Academy's do ad blockers break influencer and affiliate tracking links. An ad blocker like uBlock Origin blocks YouTube's own ads — the TrueView pre-roll, mid-roll and bumper ads Google itself sells and inserts around the video. SponsorBlock doesn't touch those ads at all. It's built for the opposite layer: content the creator has themselves recorded and placed inside the video file — a host-read endorsement, a product demo, a spoken mention. That's exactly the kind of content an influencer deal typically pays for, and it's something no conventional ad blocker can touch, because it isn't a separate ad request — it's part of the video itself. It's also a different layer again from what the Academy's copyright-claimed background music in sponsored influencer content covers: that's the platform itself muting audio over a third party's music rights, independent of whether any viewer has a browser extension installed at all.
This section is Make Influence's own reasoning, not a documented, measured finding — no published research quantifies the difference between placements.
Technically, SponsorBlock's Sponsor category is timestamp-based, not position-based: a segment can be flagged and skipped whether it sits at the start, middle or end of the video. What actually differs by position isn't a technical exemption — it's the value the tool erodes. As the Academy's own podcast sponsorships article already establishes, a mid-roll placement is typically the most expensive precisely because the listener or viewer has already committed to the content and is least likely to skip it on their own. SponsorBlock removes exactly that captive-audience advantage for any viewer who has the extension installed — regardless of whether the segment sits in the middle of the video or elsewhere. A pre-roll placement, by contrast, already faces a high natural drop-off before SponsorBlock even enters the picture, so the tool's relative marginal effect there is smaller — but that's an inference, not a measured figure.
One technical curiosity that shows how fragile the timestamp mechanic is: SponsorBlock's own official account stated in June 2024 that YouTube was testing server-side ad injection — inserting YouTube's own ads directly into the video stream itself, rather than as a separate request. Per SponsorBlock's own statement at the time: "YouTube is currently experimenting with server-side ad injection. This means that the ad is being added directly into the video stream. This breaks sponsorblock since now all timestamps are offset by the ad times" — meaning every timestamp after an ad break was suddenly shifted by the ad's own duration, throwing off the crowdsourced timestamps. Independent tech press (including Bleeping Computer and 9to5Google) confirmed the server-side insertion test around the same time. The point here isn't that YouTube deliberately targeted SponsorBlock — it's a side effect of YouTube protecting its own ad revenue — but it shows the entire mechanism behind the Sponsor category rests on a fragile technical foundation that can shift without warning.
Skipping part of a video isn't illegal — it's functionally the same as fast-forwarding a recorded broadcast. YouTube, for its part, has taken its own platform position: since 2025 it has repeatedly shown messages stating ad blockers don't comply with its own terms of service, per independent tech press. That's a platform position, not a law — in most countries using an ad blocker or a similar browser extension is legal, and this article's research found no documented case of an individual user being banned specifically for having SponsorBlock installed.
No. Some viewers later skipping the segment changes nothing about the fact that disclosure requirements still apply from the moment the content is published — see the full breakdown in influencer marketing disclosure rules in Denmark and the EU. The two obligations are separate: disclosure is about telling every viewer the content is commercial, regardless of whether they watch the full segment; SponsorBlock is purely about how many of them actually see it once it's already correctly disclosed.
IF the deal is one clearly bounded, host-read block that a viewer could easily give a precise start and end timestamp for → highest exposure to being flagged and skipped by the Sponsor category.
IF the brand integration is instead woven through the whole video (the product is used or mentioned repeatedly, not in one bounded block) → harder for a crowd to timestamp precisely as one contiguous "sponsor" segment, though not immune to it.
IF measurement is a priority → remember that a SponsorBlock skip happens entirely client-side, inside the viewer's own browser, after YouTube has already served the video — it's therefore not something YouTube's own Creator Studio analytics has any visibility into or reports as a distinct measured event. A video can look completely normal on watch time and retention in Creator Studio while a share of the real exposure to the sponsored segment disappears for viewers running the extension.
IF you're negotiating a mid-roll integration specifically for its captive-audience effect → be aware that effect is reduced for the partial, unquantifiable share of viewers running SponsorBlock or a ReVanced-based app.
The numbers below are purely hypothetical and illustrate only the mechanism itself — there is no published, reliable rate for what share of any given YouTube audience actually runs SponsorBlock, and the figure below is not an estimate of a real case or a Make Influence customer case.
Assume, purely for illustration, that a video gets 50,000 views, and that 5% of viewers (2,500 people) run SponsorBlock or an app with a built-in sponsor-skip feature. If the segment is already flagged in the database, the brand effectively loses exposure to those 2,500 viewers for that specific sponsored segment — without it showing up anywhere in YouTube's own view counts, which still count all 50,000 views. The remaining 47,500 viewers see the segment as normal. The point isn't the 5% itself — that figure is invented for the example — but that the loss is real, invisible to the platform's own analytics, and proportional to how many of that specific video's viewers have the tool installed.
In Make Influence's experience, SponsorBlock is rarely something brands ask about before a YouTube campaign — it's a blind spot, because the tool's effect never shows up in any of the numbers a campaign is normally reported on. Our recommendation isn't to let it stop a YouTube integration, but to be aware that a raw view count has never been the same thing as a guaranteed exposure count for the specific sponsored segment — in line with the other mechanisms the Academy already covers under VPNs and dark social. The more an integration is woven into the video's actual content, rather than sitting as one isolated, easily-identified block, the less precisely a crowdsourced database can describe it as one contiguous, timestamped segment.
No. SponsorBlock doesn't touch YouTube's own TrueView or bumper ads — that requires an ordinary ad blocker, see do ad blockers break influencer and affiliate tracking links.
This article's research found no crowdsourced segment-skip tool with comparable reach built for other platforms. SponsorBlock is built specifically for YouTube.
No, skipping content isn't illegal. YouTube has taken a platform position that ad-blocking-style tools don't comply with its terms of service, but that's a terms-of-service position, not a law, and this article's research found no documented case of an individual user being locked out specifically for having SponsorBlock installed.
The project's own documentation describes a crowdsourced downvoting and reputation system where incorrect submissions can be downvoted by other users — but this article's research didn't find a documented, formal dispute channel specifically for creators.
No. The disclosure requirement applies regardless of whether some viewers later skip the segment — see influencer marketing disclosure rules in Denmark and the EU.
Not immune, but harder to flag precisely as one bounded segment than a single, clearly delineated block — see the decision framework above.
No. The skip happens entirely client-side in the viewer's browser, after the video has already been delivered — it's not something either YouTube's own Creator Studio or a brand's campaign reporting has any visibility into.
Yes — it's a separate mechanism. SponsorBlock is a viewer-side browser tool; a platform's own reduced recommendation is a different, platform-side mechanism entirely. See Is There Really an Instagram or TikTok "Shadowban"? for how Instagram and TikTok document reduced recommendation on their own platforms.
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