Documentation

Python binding for curl-impersonate fork via cython. For commercial support, visit impersonate.pro.

curl_cffi\cycurl is the most popular Python binding for curl. Unlike other pure python http clients like httpx or requests, cycurl can impersonate browsers' TLS/JA3 and HTTP/2 fingerprints. If you are blocked by some website for no obvious reason, you can give cycurl a try.

Python 3.9 is the minimum supported version since v0.10.

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• Supports JA3/TLS and http2 fingerprints impersonation, including recent browsers and custom fingerprints.
• Much faster than requests/httpx, on par with aiohttp/pycurl, see benchmarks.
• Mimics the requests API, no need to learn another one.
• Pre-compiled, so you don't have to compile on your machine.
• Supports asyncio with proxy rotation on each request.
• Supports http 2.0 & 3.0, which requests does not.
• Supports websocket.
• MIT licensed.

Notes:

1. For pycurl, you need an http/3 enabled libcurl to make it work, while curl_cffi packages libcurl-impersonate inside Python wheels.
2. Since v0.11.4.

pip install cycurl --upgrade

This should work on Linux, macOS and Windows out of the box. If it does not work on you platform, you may need to compile and install curl-impersonate first and set some environment variables like LD_LIBRARY_PATH.

To install beta releases:

pip install cycurl --upgrade --pre

To install unstable version from GitHub:

git clone https://github.com/synodriver/cycurl/
cd cycurl
python setup.py bdist_wheel

On macOS, you may need to install the following dependencies:

brew install zstd nghttp2

cycurl comes with a low-level curl API and a high-level requests-like API.

import cycurl

# Notice the impersonate parameter
r = cycurl.get("https://tls.browserleaks.com/json", impersonate="chrome")

print(r.json())
# output: {..., "ja3n_hash": "aa56c057ad164ec4fdcb7a5a283be9fc", ...}
# the js3n fingerprint should be the same as target browser

# To keep using the latest browser version as `cycurl` updates,
# simply set impersonate="chrome" without specifying a version.
# Other similar values are: "safari" and "safari_ios"
r = cycurl.get("https://tls.browserleaks.com/json", impersonate="chrome")

# Randomly choose a browser version based on current market share in real world
# from: https://caniuse.com/usage-table
# NOTE: this is a pro feature.
r = cycurl.get("https://example.com", impersonate="realworld")

# To pin a specific version, use version numbers together.
r = cycurl.get("https://tls.browserleaks.com/json", impersonate="chrome124")

# To impersonate other than browsers, bring your own ja3/akamai strings
# See examples directory for details.
r = cycurl.get("https://tls.browserleaks.com/json", ja3=..., akamai=...)

# http/socks proxies are supported
proxies = {"https": "http://localhost:3128"}
r = cycurl.get("https://tls.browserleaks.com/json", impersonate="chrome", proxies=proxies)

proxies = {"https": "socks://localhost:3128"}
r = cycurl.get("https://tls.browserleaks.com/json", impersonate="chrome", proxies=proxies)

s = cycurl.Session()

# httpbin is a http test website, this endpoint makes the server set cookies
s.get("https://httpbin.org/cookies/set/foo/bar")
print(s.cookies)
# <Cookies[<Cookie foo=bar for httpbin.org />]>

# retrieve cookies again to verify
r = s.get("https://httpbin.org/cookies")
print(r.json())
# {'cookies': {'foo': 'bar'}}

cycurl supports the same browser versions as supported by the fork of curl-impersonate:

Open source version of cycurl includes versions whose fingerprints differ from previous versions. If you see a version, e.g. chrome135, were skipped, you can simply impersonate it with your own headers and the previous version.

If you don't want to look up the headers etc, by yourself, consider buying commercial support from impersonate.pro, we have comprehensive browser fingerprints database for almost all the browser versions on various platforms.

If you are trying to impersonate a target other than a browser, use ja3=... and akamai=... to specify your own customized fingerprints. See the docs on impersonation for details.

Notes:

1. Added in version 0.6.0.
2. Fixed in version 0.6.0, previous http2 fingerprints were not correct.
3. Added in version 0.7.0.
4. Added in version 0.8.0.
5. Added in version 0.9.0.
6. The version postfix -a(e.g. chrome133a) means that this is an alternative version, i.e. the fingerprint has not been officially updated by browser, but has been observed because of A/B testing.
7. Added in version 0.10.0.
8. Added in version 0.11.0.
9. Since 0.11.0, the format safari184_ios is preferred over safari18_4_ios, both are supported, but the latter is quite confusing and hard to parse.
10. Added in 0.12.0.

from cycurl import AsyncSession

async def main():
    async with AsyncSession() as s:
        r = await s.get("https://example.com")

More concurrency:

import asyncio
from cycurl import AsyncSession

urls = [
    "https://google.com/",
    "https://facebook.com/",
    "https://twitter.com/",
]

async with AsyncSession() as s:
    tasks = []
    for url in urls:
        task = s.get(url)
        tasks.append(task)
    results = await asyncio.gather(*tasks)

For low-level APIs, Scrapy integration and other advanced topics, see the docs for more details.

from cycurl import WebSocket

def on_message(ws: WebSocket, message: str | bytes):
    print(message)

ws = WebSocket(on_message=on_message)
ws.run_forever("wss://api.gemini.com/v1/marketdata/BTCUSD")

Alternatively, you can use the low-level curl-like API:

from cycurl import Curl, CURLOPT_URL, CURLOPT_WRITEDATA
from io import BytesIO

buffer = BytesIO()
c = Curl()
c.setopt(CURLOPT_URL, b'https://tls.browserleaks.com/json')
c.setopt(CURLOPT_WRITEDATA, buffer)

c.impersonate("chrome110")

c.perform()
c.close()
body = buffer.getvalue()
print(body.decode())

See the docs for more details.

If you are using scrapy, check out these middlewares:

• tieyongjie/scrapy-fingerprint
• jxlil/scrapy-impersonate
• synodriver/awsome_scrapy_utils

For low-level APIs, Scrapy integration and other advanced topics, see the docs for more details.

import asyncio
from cycurl import AsyncSession

async def main():
    async with AsyncSession() as s:
        ws = await s.ws_connect("wss://echo.websocket.org")
        await asyncio.gather(*[ws.send_str("Hello, World!") for _ in range(10)])
        await ws.flush()
        async for message in ws:
            print(message)
        await ws.close()

• Integrating with Scrapy: divtiply/scrapy-curl-cffi, jxlil/scrapy-impersonate and tieyongjie/scrapy-fingerprint.
• Integrating with requests, httpx as adapter.
• Integrating with captcha resolvers: YesCaptcha. Please see the head area for promo code and link.

• Originally forked from multippt/python_curl_cffi, which is under the MIT license.
• Headers/Cookies files are copied from httpx, which is under the BSD license.
• Asyncio support is inspired by Tornado's curl http client.
• The synchronous WebSocket API is inspired by websocket_client.
• The asynchronous WebSocket API is inspired by aiohttp.

When submitting an PR, please use a different branch other than main and check the "Allow edits by maintainers" box, so I can update your PR with lint or style fixes. Thanks!

• Using AI is neither encouraged nor discouraged, use it by your own choice.
• The bottom line here is that every line of code should be reviewed by human, and should be proven to work.
• It's not guaranteed that AI will come up with the cleanest solution, you are responsible to guide it to the right way you know.
• Fix any lint errors, make sure your code follows the established convention in this project.
• LLM tends to generate extensive or none comments, revise the comments and make sure they are concise and helpful.
• It's absolutely not acceptable to generate the entire PR summary by LLM. To communicate with other human, use words from a human.
• The only acceptable exception is to fix grammar issues if you are not a native English speaker.
• The essence here is to keep Human in the loop

You can even feed the policy above to your "copilot" to let it adjust the style for you. :P