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- dependency-name: black
  dependency-type: direct:production

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Url is constructed from str:

>>> from yarl import URL
>>> url = URL('')
>>> url

All url parts: scheme, user, password, host, port, path, query and fragment are accessible by properties:

>>> url.scheme
>>> url.path
>>> url.query_string
>>> url.query
<MultiDictProxy('arg': '1')>
>>> url.fragment

All url manipulations produce a new url object:

>>> url = URL('')
>>> url / 'foo' / 'bar'
>>> url / 'foo' % {'bar': 'baz'}

Strings passed to constructor and modification methods are automatically encoded giving canonical representation as result:

>>> url = URL('путь')
>>> url

Regular properties are percent-decoded, use raw_ versions for getting encoded strings:

>>> url.path

>>> url.raw_path

Human readable representation of URL is available as .human_repr():

>>> url.human_repr()

For full documentation please read


$ pip install yarl

The library is Python 3 only!

PyPI contains binary wheels for Linux, Windows and MacOS. If you want to install yarl on another operating system (like Alpine Linux, which is not manylinux-compliant because of the missing glibc and therefore, cannot be used with our wheels) the the tarball will be used to compile the library from the source code. It requires a C compiler and and Python headers installed.

To skip the compilation you must explicitly opt-in by setting the YARL_NO_EXTENSIONS environment variable to a non-empty value, e.g.:

$ YARL_NO_EXTENSIONS=1 pip install yarl

Please note that the pure-Python (uncompiled) version is much slower. However, PyPy always uses a pure-Python implementation, and, as such, it is unaffected by this variable.


YARL requires multidict library.

API documentation

The documentation is located at

Why isn't boolean supported by the URL query API?

There is no standard for boolean representation of boolean values.

Some systems prefer true/false, others like yes/no, on/off, Y/N, 1/0, etc.

yarl cannot make an unambiguous decision on how to serialize bool values because it is specific to how the end-user's application is built and would be different for different apps. The library doesn't accept booleans in the API; a user should convert bools into strings using own preferred translation protocol.

Comparison with other URL libraries

  • furl (

    The library has rich functionality but the furl object is mutable.

    I'm afraid to pass this object into foreign code: who knows if the code will modify my url in a terrible way while I just want to send URL with handy helpers for accessing URL properties.

    furl has other non-obvious tricky things but the main objection is mutability.

  • URLObject (

    URLObject is immutable, that's pretty good.

    Every URL change generates a new URL object.

    But the library doesn't do any decode/encode transformations leaving the end user to cope with these gory details.

Source code

The project is hosted on GitHub

Please file an issue on the bug tracker if you have found a bug or have some suggestion in order to improve the library.

The library uses Azure Pipelines for Continuous Integration.

Discussion list

aio-libs google group:!forum/aio-libs

Feel free to post your questions and ideas here.

Authors and License

The yarl package is written by Andrew Svetlov.

It's Apache 2 licensed and freely available.