Ja3Requests

Ja3Requests is a http request library that can customize ja3 or h2 fingerprints.

TLS handshakes and records are implemented by this project; cryptographic primitives use cryptography. See the wire-control contract for exact extension ordering, actual ClientHello inspection, opt-in P-384 and capture-backed browser-profile limitations. Browser-inspired presets are not a guarantee of complete browser impersonation. The explicit TlsConfig.from_browser("chrome", 154) profile is a supported subset with a different JA3 from the captured browser; ECH and post-quantum groups are not implemented. Implicit Chrome selection remains at version 124.

中文文档

>>> import ja3requests
>>> session = ja3requests.Session()
>>> response = session.get("http://www.baidu.com/")
>>> response
<Response [200]>
>>> response.status_code
200
>>> response.headers
{'Content-Length': '405968', 'Content-Type': 'text/html; charset=utf-8', 'Server': 'BWS/1.1', 'Vary': 'Accept-Encoding', 'X-Ua-Compatible': 'IE=Edge,chrome=1', ...}
>>> response.text
'<!DOCTYPE html><!--STATUS OK--><html><head><meta http-equiv="Content-Type" content="text/html;char...'

Ja3Requests supports HTTP/1.1 over HTTP and HTTPS. HTTPS connections can also negotiate HTTP/2 with ALPN. Version 2.0 defaults to verified TLS 1.3 with TLS 1.2 ECDHE/GCM fallback. Version 2.4.0 release links: PyPI and GitHub. This release adds optional H2 Huffman encoding, indexing exclusions and per-request HEADERS priority. It also corrects synchronous 307/308 body replay, hook edits and proxy/TLS policy handling; see release notes for scope and limits.

Installing Ja3Requests and Supported Versions

Ja3Requests is available on PyPI:

$ python -m pip install ja3requests

Ja3Requests officially supports Python 3.7+.

HTTPS Certificate Verification

Version 2.0 verifies server certificates by default. TlsConfig(), Session() and module-level requests use the secure TLS 1.3/TLS 1.2 ECDHE-GCM profile. The explicit secure profile remains available:

import ja3requests

config = ja3requests.TlsConfig.secure()
with ja3requests.Session(tls_config=config) as session:
    response = session.get("https://example.com/")

The secure profile verifies certificates, offers only TLS 1.3 suites and TLS 1.2 ECDHE/AES-128/256-GCM suites, and uses HTTP/1.1 ALPN. It does not impersonate a browser. Its TLS 1.3 ClientHello includes X25519 and P-256 key shares by default. To send only X25519 initially while allowing a P-256 HelloRetryRequest, set config.key_share_groups = [29] before creating the Session. Version 2.0.1 also supports P-384 through explicit supported_groups/key_share_groups configuration, including HelloRetryRequest. The secure defaults remain [29, 23] (X25519/P-256); see the P-384 configuration example. TLS 1.3 connections also process server KeyUpdate messages, including requests to update the client sending key. Session caches can resume TLS 1.3 connections with in-memory tickets and PSK-DHE; 0-RTT is not supported. TLS 1.2 connections can resume an in-memory Session ID, or a session ticket when SessionTicketExtension() is configured. The original session must use extended master secret and match the current certificate policy. Import the extension from ja3requests.protocol.tls.extensions. You can also enable verification for one request with verify=True. For a destination-specific JA3 string, call config.get_ja3_string(server_name="example.com") so the SNI extension is included. A pooled session can run concurrent HTTP/2 requests, including requests with bodies, on one TLS connection. Responses are matched by stream ID, and request DATA respects the peer's frame size and connection and stream flow-control windows. HTTP/1.1 connections remain serial. Server push is disabled because pushed responses are not supported; an explicit SETTINGS_ENABLE_PUSH=1 configuration is rejected. Custom H2 SETTINGS preserve the supplied mapping/pair order and field set. Pseudo-header order and initial legacy PRIORITY signals are configurable; priority signals do not affect request scheduling. See the fingerprint guide for controls and push boundaries. Version 2.1.0 reads HTTP/1.1 and HTTP/2 response bodies incrementally with stream=True, including project TLS record decryption and gzip/deflate/Brotli decoding. Version 2.0.1 buffered the full body. Close responses when stopping early; iteration does not retain a replay cache. See streaming and memory limits for ownership, decoding errors, read timeouts and the distinction between chunk size and total memory.

An explicit verify=True or verify=False overrides the session setting for that request, including redirects. TlsConfig.legacy() explicitly restores the 1.x TLS 1.2 RSA/AES-CBC offer and disables certificate verification. The new defaults change ClientHello/JA3 fingerprints and reject untrusted, expired or wrong-host certificates. See the TLS defaults migration guide for private CA trust, hostname/SNI behavior, request overrides, legacy-server setup, and the 2.0 compatibility changes. Browser preset factories retain their explicit wire settings and now verify certificates; custom builders inherit the source configuration's verification and extensions. See release notes. The secure-profile matrix records verified combinations and environment limits; local protocol tests describe the underlying cases.

TLS 1.2 and TLS 1.3 client-certificate authentication use client_cert and client_key when the server requests a certificate. Configured TLS 1.3 client certificates do not use PSK ticket resumption. TLS 1.3 post-handshake client authentication is opt-in: append PostHandshakeAuthExtension() to config.extensions before creating a session. It uses the same certificate and key settings; with no client certificate, it sends an empty Certificate message. This extension changes the ClientHello fingerprint.

How To Use

The user guide and generated API reference cover configuration, fingerprints, TLS, proxies, retries, hooks, cookies and connection pooling. The documentation build guide explains how to build and check the site locally. Version 2.1.0 also includes public type annotations and a packaged py.typed marker, a synchronous performance suite, and a task roadmap.

Version 2.1.0 provides native AsyncSession, AsyncResponse and AsyncConnectionPool, retaining project-owned TLS/H2 with asyncio socket waits. See the async guide and runnable local async example.

import asyncio
from ja3requests import AsyncSession

async def main():
    async with AsyncSession() as session:
        async with await session.get("https://example.com/data", stream=True) as response:
            response.raise_for_status()
            async for chunk in response.aiter_content(65536):
                print(len(chunk))

if __name__ == "__main__":
    asyncio.run(main())

For async full-body access use await response.read(), await response.text() or await response.json(); .content reads only a completed cache. Both async body modes reject invalid compression. Explicit async pools are borrowed and must be closed by their owner after all sessions finish.

For an incrementally consumed response, keep its lifetime explicit:

from ja3requests import Session
from ja3requests.pool import ConnectionPool

with Session(pool=ConnectionPool()) as session:
    with session.get("https://example.com/data", stream=True, timeout=(3, 10)) as response:
        response.raise_for_status()
        for chunk in response.iter_content(chunk_size=65536):
            print(len(chunk))

Unreasonable Request Method

Ja3Requests supports multiple request methods such as Get, Post, Put, Delete, etc.

import ja3requests

session = ja3requests.session()
# Get
session.get("http://example.com/")

# POST
session.post("http://example.com/")
...

Use The Headers Attribute

import ja3requests

headers = {
    "Accept": "*/*",
    "Accept-Encoding": "gzip, deflate, br",
    "Connection": "keep-alive",
    "Host": "example.com",
    "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:120.0) Gecko/20100101 Firefox/120.0"
}

session = ja3requests.session()

response = session.get("http://example.com/", headers=headers)
print(response)

Use The Params Attribute

import ja3requests

session = ja3requests.session()

params = {
    "page": 1,
    "page_size": 100
}
# OR
# params = "page=1&page_zie=100"
# OR
# params = [("page", 1), ("page_size", 100)]
# OR
# params = (("page", 1), ("page_size", 100))
response = session.get("http://example.com/", params=params)
print(response)

Post Data

import ja3requests

session = ja3requests.session()

data = {
    "username": "admin",
    "password": "admin"
}
# OR (Content-Type: application/x-www-form-urlencoded)
# data = "username=admin&password=admin"
# OR
# data = [("username", "admin"), ("password": "admin")]
# OR
# data = (("username", "admin"), ("password", "admin"))

response = session.post("http://example.com/", data=data)
print(response)

Post Json

import ja3requests

session = ja3requests.session()

data = {
    "username": "admin",
    "password": "admin"
}
# OR
# import json
# data = json.dumps(data)

response = session.post("http://example.com/", json=data)
print(response)

Post Files

import ja3requests

session = ja3requests.session()

with open("/user/home/demo.txt", "r") as f:
    response = session.post("http://example.com/", files={"field_name": f})
print(response)

# OR
# response = session.post("http://example.com/", files={"field_name": "/user/home/demo.txt"})

# multiple files
# response = session.post("http://example.com/", files={"field_name": ["/user/home/demo.txt", "/user/home/demo2.txt"]})

Use the proxies attribute

import ja3requests

session = ja3requests.session()

proxies = {
    "http": "127.0.0.1:7890",
    "https": "127.0.0.1:7890"
}

response = session.get("http://example.com/", proxies=proxies)
print(response)

# With Authorization information
# proxies = {
#     "http": "user:password@127.0.0.1:7890",
#     "https": "user:password@127.0.0.1:7890"
# }

Use the cookies attribute

import ja3requests

session = ja3requests.session()
cookies = {
    "sessionId": "xxxx",
    "userId": "xxxx",
}
# OR
# cookies = "sessionId=xxxx; userId=xxxx;...."
# OR
# cookies = <CookieJar()>

# Or set cookies in headers = {"Cookies": "sessionId=xxxx; userId=xxxx;...."}

response = session.get("http://example.com/", cookies=cookies)
print(response)

Persist Cookies to a file

Use session.save_cookies(path) and session.load_cookies(path) for explicit JSON persistence across process restarts. Loading replaces stored Cookies by default; merge=True merges by domain/path/name. Session/discard Cookies require include_session=True on both operations, and expired Cookies are always skipped. Files can contain login tokens in plaintext and use 0600 permissions on POSIX. See Cookie file persistence for scope, format, limits, failure behavior and the runnable example.

Allow Redirects

import ja3requests

session = ja3requests.session()

# Default allow_redirects=True
response = session.get("http://example.com/", allow_redirects=False)
print(response)

Reference

• HTTP
• HTTP-RFC
• TLS v1.1-RFC
• TLS v1.2-RFC
• TLS v1.3-RFC
• IANA Registry Updates for TLS and DTLS
• HTTP2-RFC
• SSL-CONFIG-GENERATOR
• SHA-256/384 and AES GCM
• ECC Cipher Suites for TLS 1.2 and Earlier
• TLS EXTENSIONS