fastavro

Because the Apache Python avro package is written in pure Python, it is relatively slow. In one test case, it takes about 14 seconds to iterate through a file of 10,000 records. By comparison, the JAVA avro SDK reads the same file in 1.9 seconds.

The fastavro library was written to offer performance comparable to the Java library. With regular CPython, fastavro uses C extensions which allow it to iterate the same 10,000 record file in 1.7 seconds. With PyPy, this drops to 1.5 seconds (to be fair, the JAVA benchmark is doing some extra JSON encoding/decoding).

fastavro supports the following Python versions:

Python 3.9
Python 3.10
Python 3.11
Python 3.12
Python 3.13
Python 3.14
PyPy3

Supported Features

File Writer
File Reader (iterating via records or blocks)
Schemaless Writer
Schemaless Reader
JSON Writer
JSON Reader
Codecs (Snappy, Deflate, Zstandard, Bzip2, LZ4, XZ)
Schema resolution
Aliases
Logical Types
Parsing schemas into the canonical form
Schema fingerprinting

Missing Features

Anything involving Avro's RPC features

Documentation

Documentation is available at http://fastavro.readthedocs.io/en/latest/

Installing

fastavro is available both on PyPI

pip install fastavro

and on conda-forge conda channel.

conda install -c conda-forge fastavro

Contributing

Bugs and new feature requests typically start as GitHub issues where they can be discussed. I try to resolve these as time affords, but PRs are welcome from all.
Get approval from discussing on the GitHub issue before opening the pull request
Tests must be passing for pull request to be considered

Developer requirements can be installed with pip install -r developer_requirements.txt. If those are installed, you can run the tests with ./run-tests.sh. If you have trouble installing those dependencies, you can run docker build . to run the tests inside a Docker container. This won't test on all versions of Python or on PyPy, so it's possible to still get CI failures after making a pull request, but we can work through those errors if/when they happen. .run-tests.sh only covers the Cython tests. In order to test the pure Python implementation, comment out python setup.py build_ext --inplace and re-run.

NOTE: Some tests might fail when running the tests locally. An example of this is this codec tests. If the supporting codec library is not available, the test will fail. These failures can be ignored since the tests will on pull requests and will be run in the correct environments with the correct dependencies set up.

Platform	CPython 3.9	CPython 3.10	CPython 3.11	CPython 3.12	CPython 3.13	CPython 3.14	CPython (additional flags: t) 3.13	CPython (additional flags: t) 3.14
macosx_10_13_universal2
macosx_10_15_universal2
macosx_10_9_universal2
manylinux2014_aarch64
manylinux2014_x86_64
manylinux_2_17_aarch64
manylinux_2_17_x86_64
manylinux_2_28_aarch64
manylinux_2_28_x86_64
musllinux_1_2_aarch64
musllinux_1_2_x86_64
win_amd64

fastavro 1.12.1

Development Status

Intended Audience

Operating System

Programming Language

Topic

fastavro

Supported Features

Missing Features

Documentation

Installing

Contributing

Releasing

Changes

Contact

Wheel compatibility matrix

Files in release