[Bug]: Not Compatible with Python 3.14 (lxml dependency failure)

[rayliverified]

crawl4ai version

0.8.6

Summary

Crawl4AI installation fails in Python 3.14 environment due to lxml~=5.3.
Using lxml 6.0.2 works!

AI Analysis

---

pip install crawl4ai fails on Windows with Python 3.14 due to lxml~=5.3 source build error

Body

Describe the bug

Installing crawl4ai on Windows with Python 3.14 fails during dependency installation when pip tries to build lxml from source.

The failure appears related to Crawl4AI depending on lxml~=5.3, which resolves to lxml 5.4.0 in my environment. On Windows + Python 3.14, pip does not appear to find a compatible wheel and falls back to a native source build, which then fails because libxml2 headers/libraries are not available.

To Reproduce

1. On Windows, create a fresh virtual environment with Python 3.14
2. Run:

pip install crawl4ai

3. Installation fails while building lxml

Expected behavior

pip install crawl4ai should either:

• install successfully on Python 3.14, or
• fail early with a clear message that Python 3.14 is not currently supported

Actual behavior

Installation fails while building lxml from source.

Error output

Building wheels for collected packages: lxml
  Building wheel for lxml (pyproject.toml) ... error
  error: subprocess-exited-with-error

  × Building wheel for lxml (pyproject.toml) did not run successfully.
  │ exit code: 1

...
fatal error C1083: Cannot open include file: 'libxml/xmlversion.h': No such file or directory
Compile failed: command '...\\cl.exe' failed with exit code 2

...
fatal error C1083: Cannot open include file: 'libxml/xpath.h': No such file or directory

*********************************************************************************
Could not find function xmlXPathInit in library libxml2. Is libxml2 installed?
Is your C compiler installed and configured correctly?
*********************************************************************************

ERROR: Failed building wheel for lxml
Failed to build lxml
error: failed-wheel-build-for-install

× Failed to build installable wheels for some pyproject.toml based projects
╰─> lxml

Environment

• OS: Windows 11
• Python: 3.14.2
• pip: latest available at time of test
• Compiler/tooling: Visual Studio 2022 C++ tools detected in build log

Additional context

Current Crawl4AI PyPI metadata appears to declare:

• Requires-Python: >=3.10
• Python classifiers for:
  • 3.10
  • 3.11
  • 3.12
  • 3.13

But not 3.14.

Current dependency metadata also includes:

lxml~=5.3

So this may be a Python 3.14 compatibility gap caused by the current lxml version range, rather than a general Windows install problem.

Suggested fix

Possible options:

1. Explicitly document that Python 3.14 is not yet supported
2. Add a clearer install-time guard or message for unsupported Python versions
3. Relax/update the lxml dependency if a newer version line works with Python 3.14
4. Document a recommended Python version such as 3.12 or 3.13 for Windows users

Workaround

Using Python 3.12 or 3.13 appears to be the safest workaround.

---

Current Behavior

Installation fails with error.

Is this reproducible?

Yes

OS

Windows

Python version

3.14

Browser

No response

Browser version

No response

Error logs & Screenshots (if applicable)

No response

[sinni800]

lxml 5.4 is also a whole year old at this point