Polyfill
Polyfill.io is an open-source 
JavaScript library that provides modern web API features to older browsers that do not natively support them.
After a supply chain attack in 2024 involving its cdn.polyfill.io domain, the service was discontinued and is now safely mirrored and maintained by 
Cloudflare under independent management.
According to our data, Polyfill is the 4th most popular JavaScript library on the web.
It has 12.3% of the JavaScript library market share and is detected on 9% of all websites.
- 🏠 Website
- 🏷️ Previous name
- Polyfill.io
- 🔗 Links
💸 Pricing
Polyfill is available for free.
📊 Rankings and Market Share
- JavaScript Libraries
- Rank: 4
- Market share: 12.3%
🏆 Polyfill Awards
- 🥈 Second most popular in Russia in the JavaScript Libraries category.
- 🥈 Second most popular in Belarus in the JavaScript Libraries category.
- 🥈 Second most popular in Jamaica in the JavaScript Libraries category.
- 🥈 Second most popular in Curacao in the JavaScript Libraries category.
- 🥈 Second most popular in the Turks and Caicos Islands in the JavaScript Libraries category.
- 🥉 Third most popular in the United Kingdom in the JavaScript Libraries category.
- 🥉 Third most popular in France in the JavaScript Libraries category.
- 🥉 Third most popular in the Netherlands in the JavaScript Libraries category.
- 🥉 Third most popular in Switzerland in the JavaScript Libraries category.
- 🥉 Third most popular in Belgium in the JavaScript Libraries category.
⚡ Sites Using Polyfill
We have data on 316,545 websites that use the Polyfill JavaScript library. Here is a list of some of the top ranked ones.
The highest rated site using Polyfill is 
youtube.com.
| # | Website | Rank | Country | Language |
|---|---|---|---|---|
| 1 | youtube.com |
#4 | United States | English |
| 2 | #19 | United States | English | |
| 3 |  reddit.com |
#25 | United States | American English |
| 4 | #36 | Korea | Korean | |
| 5 | #38 | United States | English | |
| 6 | #55 | English | ||
| 7 |  wordpress.com |
#83 | United States | English |
| 8 | #84 | Switzerland | English | |
| 9 | #88 | Switzerland | English | |
| 10 |  baidu.com |
#90 | Hong Kong | Chinese |
| 11 |  amazon.co.uk |
#96 | United Kingdom | British English |
| 12 |  amazon.de |
#122 | Germany | English |
| 13 | #140 | United States | American English | |
| 14 |  qq.com |
#144 | China | Chinese |
| 15 | #146 | United Kingdom | English | |
| 16 | #160 | Korea | Korean | |
| 17 |  yandex.com |
#195 | Russia | English |
| 18 |  bilibili.com |
#212 | China | Chinese |
| 19 | #222 | Singapore | English | |
| 20 | #225 | Korea | Korean |
📈 Usage Statistics
Most of the sites that use Polyfill:
- are located in the United States
- have content in English
- use the .com domain extension
- fall into the Business category.
Most of the sites using Polyfill are from the United States, the United Kingdom, and Russia.
- United States 18.4%
- United Kingdom 6.5%
- Russia 5.7%
- Japan 5.5%
- Spain 4.8%
- Germany 4.5%
- Italy 4.3%
- France 4.2%
- Australia 4.1%
- Other 42%
Most Polyfill users speak English, Spanish, or Russian.
- English 50.6%
- Spanish 6.7%
- Russian 5.8%
- Japanese 4.9%
- German 4.4%
- French 4.3%
- Italian 3.6%
- Dutch 2.7%
- Portuguese 2.6%
- Other 14.4%
The Polyfill JavaScript library is especially popular on .com and .org top-level domains.
- .com 42.6%
- .org 6.4%
- .ru 4.1%
- .com.au 2.6%
- .de 2.6%
- .co.uk 2.6%
- .it 2.4%
- .net 2.3%
- .fr 1.6%
- Other 32.8%
The primary market segments for websites utilizing Polyfill include business, marketing and merchandising, and online shopping.
- Business 20.1%
- Marketing/Merchandising 12.8%
- Online Shopping 8.5%
- Education/Reference 6.1%
- Blogs/Wiki 5.8%
- Internet Services 5.1%
- Travel 4.3%
- Health 3.8%
- Entertainment 3.6%
- Other 29.9%
🔢 Polyfill Versions
The most popular version of Polyfill is 3.109, used by 17.6% of sites where versions were detected. In addition, 11.8% of sites use Polyfill 1.0, and 11.8% use Polyfill 6.26.
- 3.109 17.6%
- 1.0 11.8%
- 6.26 11.8%
- 0.1 7.8%
- 7.0 7.8%
- 7.11 7.8%
- 7.12 7.8%
- 6.23 3.9%
- 7.4 3.9%
- Other 19.8%
🕵️ Similar Technologies
These are some of the best Polyfill alternatives.
Core-js🆚 Compare Alternatives
Compare Polyfill to…
- 🕵️ Similar libraries
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💬 Frequently Asked Questions
Can I use Polyfill for free?
Yes, it is a free JavaScript library.
Which country uses Polyfill the most?
The majority of Polyfill users are from the United States.
Who uses Polyfill?
According to our data, Polyfill is used on thousands of sites, including youtube.com, netflix.com, and
reddit.com.
Is Polyfill used on government websites?
In total, we found Polyfill on 125 government sites in the United States.
Do academic institutions use Polyfill?
Yes, quite a few! In total, we know of 357 academic websites in the United States that use Polyfill.
How does Polyfill compare to the competition?
Polyfill is one of the most popular JavaScript libraries, second only to 
jQuery, 
Facebook SDK, and 
Swiper.
What are the alternatives to Polyfill?
Alternatives and possible competitors to Polyfill may include 
Regenerator, 
Babel.
👉 See Also
- ✨ Related technologies
🗃️ About This Data
- We evaluate the popularity of technologies based on the number of websites where we detect their usage.
- Technologies without a detectable web footprint, and those we do not track, are not reflected in the calculated market share.
- This report is based on the analysis of 3,532,023 websites.
- Statistics were last calculated on .
- For more details, see our methodology and disclaimer.