Packages
To import a Python package, add the package name to the requirements.txt file within the same directory as your wrangler.toml configuration file.
For example, if your Worker depends on FastAPI, you would add the following:
requirements.txtfastapi Package versioning
In the example above, you likely noticed that there is no explicit version of the Python package declared in requirements.txt.
In Workers, Python package versions are set via Compatibility Dates and Compatibility Flags. Given a particular compatibility date, a specific version of the Pyodide Python runtime is provided to your Worker, providing a specific set of Python packages pinned to specific versions.
As new versions of Pyodide and additional Python packages become available in Workers, we will publish compatibility flags and their associated compatibility dates here on this page.
Supported Packages
As of March April 2, 2024, the following Python packages are provided directly by the Workers runtime:
- aiohttp: 3.9.3
- aiohttp-tests: 3.9.3
- aiosignal: 1.3.1
- annotated-types: 0.6.0
- annotated-types-tests: 0.6.0
- anyio: 4.2.0
- async-timeout: 4.0.3
- attrs: 23.2.0
- certifi: 2024.2.2
- charset-normalizer: 3.3.2
- distro: 1.9.0
- fastapi: 0.110.0
- frozenlist: 1.4.1
- h11: 0.14.0
- h11-tests: 0.14.0
- hashlib: 1.0.0
- httpcore: 1.0.4
- httpx: 0.27.0
- idna: 3.6
- jsonpatch: 1.33
- jsonpointer: 2.4
- langchain: 0.1.8
- langchain-core: 0.1.25
- langchain-openai: 0.0.6
- langsmith: 0.1.5
- lzma: 1.0.0
- micropip: 0.6.0
- multidict: 6.0.5
- numpy: 1.26.4
- numpy-tests: 1.26.4
- openai: 1.12.0
- openssl: 1.1.1n
- packaging: 23.2
- pydantic: 2.6.1
- pydantic-core: 2.16.2
- pydecimal: 1.0.0
- pydoc-data: 1.0.0
- pyyaml: 6.0.1
- regex: 2023.12.25
- regex-tests: 2023.12.25
- requests: 2.31.0
- six: 1.16.0
- sniffio: 1.3.0
- sniffio-tests: 1.3.0
- sqlite3: 1.0.0
- ssl: 1.0.0
- starlette: 0.36.3
Looking for a package not listed here? Tell us what you’d like us to support by opening a discussion on Github.
HTTP Client Libraries
Only HTTP libraries that are able to make requests asynchronously are supported. Currently, these include aiohttp and httpx. You can also use the fetch() API from JavaScript, using Python Workers’ foreign function interface to make HTTP requests.