Extensionpay
Open-source API letting developers accept subscription and one-time payments in browser extensions
Overview
Extensionpay (extensionpay.com): Open-source API letting developers accept subscription and one-time payments in browser extensions. Category on TopCheckouts: Developer tools.
In September 2026, Similarweb estimates about 12,894 visits went from Extensionpay to a checkout payment page — #291 of the 607 sites we track. That is 9% up from the April–June monthly average of 11,800.
Total website visits that month were about 126,312 (Similarweb 3-month total, split by month-over-month change). Roughly 10.2 of every 100 visits reached the checkout page.
Largest September traffic sources: direct 70%, social 22%, search 4%. (Top channel measured; others estimated by rank.)
New users mostly come from the product spreading itself: the site shows open source, and direct plus brand search is about 75%, plus shares via WhatsApp. Most new users are brought in by existing ones.
Pricing: 5% per transaction, no monthly fee.
Checkout visits over time
By checkout
| Checkout | Apr–Jun avg | Jul | Aug | Sep |
|---|---|---|---|---|
| checkout.stripe.com | 11,800 | 12,741 | 13,515 | 12,894 |
Similarweb referral data; months derived from 1/2/3/6-month shares.
Website traffic & engagement
Traffic sources
Similarweb top channel measured, others estimated by rank
How the new-user source is computed
Direct + brand search 74.7% · Direct and brand search count as viral only when the site shows sharing mechanics; the largest share wins, under 5% means Other.
Search & AI
Social & referrals
Visitor countries
Product & pricing
“'ExtensionPay is an open-source API to accept payments in browser extensions'; 'over 750 stars on Github'”Quote from the site
FAQ
How many checkout visits does Extensionpay get per month?
In September 2026, Similarweb estimates about 12,894 visits went from Extensionpay to a checkout payment page — #291 of the 607 sites we track. That is 9% up from the April–June monthly average of 11,800.
Where do Extensionpay's new users come from?
New users mostly come from the product spreading itself: the site shows open source, and direct plus brand search is about 75%, plus shares via WhatsApp. Most new users are brought in by existing ones.
How much does Extensionpay cost?
Pricing: 5% per transaction, no monthly fee.
Similar sites
About the data
Checkout visits are Similarweb's estimate of visits from this site to a checkout payment page; opening checkout is not paying, so this is not revenue. See the methodology for how website visits and source mix are computed. Updated 2026-10-21.