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Browser Extensions · head to head

SimilarWeb vs Tampermonkey

SimilarWeb logo

SimilarWeb

Browser Extensions

Website traffic and competitive analysis

From
Free
Rated
-
Full reviewWebsite
Tampermonkey logo

Tampermonkey

Browser Extensions

The most popular userscript manager

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: SimilarWeb browser extension data accuracy is lower than full platform; Tampermonkey only source code up to version 2.9 is GPLv3; all newer versions are distributed under a proprietary license despite the extension itself being free to use
  • They diverge on capability: SimilarWeb covers Traffic analytics, Tampermonkey covers Userscript management.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which SimilarWeb and Tampermonkey actually diverge.

Attributes where SimilarWeb and Tampermonkey differ
AttributeSimilarWebTampermonkey
Pricing modelfreemiumopen-source
PlatformsWeb, Browser ExtensionWeb, Windows, macOS, Linux, Android
Founded20072010

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Browser Extensions).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in SimilarWeb

  • Traffic analytics
  • Audience insights
  • Competitor research
  • Industry analysis

Only in Tampermonkey

  • Userscript management
  • Script editor
  • Auto-update
  • Cloud sync
  • Safari support
  • Opera support

Both cover

  • Chrome support
  • Firefox support
  • Edge support

What people use each for

The jobs each tool is most often brought in to do.

SimilarWeb

  • Analyzing competitor advertising across display, search, socialnot Tampermonkey
  • Understanding traffic loss to search and AI recommendationsnot Tampermonkey
  • Tracking brand visibility across ChatGPT and AI chatbotsnot Tampermonkey
  • Optimizing Amazon product placement with marketplace analyticsnot Tampermonkey
  • Identifying high-intent prospects at optimal buying momentsnot Tampermonkey

Tampermonkey

  • Auto-run custom JavaScript to add features to specific websitesnot SimilarWeb
  • Block ads, remove clutter, or reformat page layout via community/personal userscriptsnot SimilarWeb
  • Run scripts sourced from Greasy Fork or similar userscript repositoriesnot SimilarWeb
  • Automate repetitive web tasks such as form-filling or redirect skipping via installed scriptsnot SimilarWeb

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

SimilarWeb

  • Browser extension data accuracy is lower than full platform
  • Full platform pricing is not transparent and requires quote-based inquiry

Tampermonkey

  • Only source code up to version 2.9 is GPLv3; all newer versions are distributed under a proprietary license despite the extension itself being free to use
  • Under Manifest V3, GM_webRequest is not (yet) supported
  • Under Manifest V3, GM_xmlhttpRequest fires only one progress event instead of streaming progress, requiring a responseType: 'stream' workaround
  • Since v5.3.2, Chrome/Edge (MV3) requires the user to manually enable Developer Mode, or from Chrome 138+ a per-extension 'Allow User Scripts' toggle, before any userscript will run

Pricing, plan by plan

SimilarWeb

Free
  • FreeFree
    • Traffic overview
    • Engagement metrics
    • Similar sites

Tampermonkey

Free

No published plan breakdown. See the Tampermonkey review.

Which should you pick?

Choose SimilarWeb if

  • You need traffic analytics.
  • You want to start without paying.
  • You work on Web, Browser Extension.
  • You also want audience insights.
SimilarWeb review

Choose Tampermonkey if

  • You need userscript management.
  • You want to start without paying.
  • You work on Web, Windows, macOS, Linux, Android.
  • You also want script editor.
Tampermonkey review

Questions people ask

Is SimilarWeb or Tampermonkey better?
Neither clearly leads. SimilarWeb starts at Free and Tampermonkey at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, SimilarWeb or Tampermonkey?
SimilarWeb starts at Free and Tampermonkey at Free.
Does SimilarWeb or Tampermonkey run on more platforms?
SimilarWeb runs on Web, Browser Extension. Tampermonkey runs on Web, Windows, macOS, Linux, Android.
Can I use SimilarWeb for free?
Both have a free tier, so you can try either at no cost before committing.
What is SimilarWeb best used for?
SimilarWeb is most often used for analyzing competitor advertising across display, search, social, understanding traffic loss to search and ai recommendations, tracking brand visibility across chatgpt and ai chatbots, optimizing amazon product placement with marketplace analytics. Of those, analyzing competitor advertising across display, search, social and understanding traffic loss to search and ai recommendations are not what Tampermonkey is typically brought in for.
What can SimilarWeb do that Tampermonkey cannot?
SimilarWeb covers Traffic analytics, Audience insights, Competitor research, Industry analysis. Tampermonkey covers Userscript management, Script editor, Auto-update, Cloud sync. Both handle Chrome support, Firefox support, Edge support.

Answered from the vendors’ own pages

SimilarWeb: How much does Similarweb cost?

Similarweb does not publish pricing. Custom packages are available for businesses and enterprises. Self-service options are available for entrepreneurs and small teams. Customers must start a free trial or contact sales to receive a quote.

Source
Tampermonkey: How much does Tampermonkey cost?

Tampermonkey is completely free for all versions and across all supported browsers including Chrome, Edge, Safari, Opera, and Firefox.

Source
SimilarWeb: Does Similarweb offer a free trial?

Yes. Similarweb offers free trials for its various products. Users can start a free trial through their registration page or contact support to switch between different product trials.

Source
Tampermonkey: Is Tampermonkey available on all browsers?

Yes, Tampermonkey is available on Chrome 120 and later, Microsoft Edge, Safari, Opera Next, and Firefox with no cost.

Source
SimilarWeb: What products does Similarweb offer?

Similarweb offers the Competitive Intelligence Suite, Strategic SEO Suite, Ads Intelligence Suite, Gen AI Intelligence Suite, AI Studio with natural language queries, custom data feeds, API access, and managed services with custom dashboards.

Source
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