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Python interface to the ecCodes GRIB and BUFR decoder/encoder

Project description

Python 3 interface to decode and encode GRIB and BUFR files via the ECMWF ecCodes library.


  • reads and writes GRIB 1 and 2 files,

  • reads and writes BUFR 3 and 4 files,

  • supports all modern versions of Python 3.9, 3.8, 3.7 and PyPy3,

  • works on most Linux distributions and MacOS, the ecCodes C-library is the only system dependency,

  • PyPI package can be installed without compiling, at the cost of being twice as slow as the original ecCodes module,

  • an optional compile step makes the code as fast as the original module but it needs the recommended (the most up-to-date) version of ecCodes.


  • Microsoft Windows support is untested.


The package is installed from PyPI with:

$ pip install eccodes

System dependencies

The Python module depends on the ECMWF ecCodes library that must be installed on the system and accessible as a shared library.

On a MacOS with HomeBrew use:

$ brew install eccodes

Or if you manage binary packages with Conda use:

$ conda install -c conda-forge eccodes

As an alternative you may install the official source distribution by following the instructions at

You may run a simple selfcheck command to ensure that your system is set up correctly:

$ python -m eccodes selfcheck
Found: ecCodes v2.21.0.
Your system is ready.


Refer to the ecCodes documentation pages for usage.

Experimental features

Fast bindings

To test the much faster CFFI API level, out-of-line mode you need the ecCodes header files. Then you need to clone the repo in the same folder as your ecCodes source tree, make a pip development install and custom compile the binary bindings:

$ git clone
$ cd eccodes-python
$ pip install -e .
$ python

To revert back to ABI level, in-line more just remove the compiled bindings:

$ rm gribapi/_bindings.*

Project resources




The main repository is hosted on GitHub, testing, bug reports and contributions are highly welcomed and appreciated:

Please see the CONTRIBUTING.rst document for the best way to help.



See also the list of contributors who participated in this project.


© Copyright 2017- ECMWF.

This software is licensed under the terms of the Apache Licence Version 2.0 which can be obtained at

In applying this licence, ECMWF does not waive the privileges and immunities granted to it by virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.

Changelog for eccodes-python

1.5.0 (2022-08-25)

  • ECC-1404: Add the grib_get_gaussian_latitudes() function

  • ECC-1405: Add new function: codes_any_new_from_samples

  • ECC-1415: Implement a higher-level Python interface (still experimental)

  • ECC-1429: Remove the file ‘eccodes/’

  • GitHub pull request #62: add pypi badge

1.4.2 (2022-05-20)

  • ECC-1389: Drop Python version 3.5 and 3.6

  • ECC-1390: NameError: name ‘GribInternalError’ is not defined

  • Add test for GRIB bitmap

1.4.1 (2022-03-03)

  • ECC-1351: Support numpy.int64 in codes_set() and codes_set_long()

  • ECC-1317: Data file tiggelam_cnmc_sfc.grib2 not included in released tar file

1.4.0 (2021-12-03)

  • ECC-1234: Remove the experimental high-level interface

  • ECC-1282: Add codes_dump()

1.3.4 (2021-08-27)

  • Update documentation

1.3.3 (2021-06-21)

  • ECC-1246: UnicodeDecodeError when parsing BUFR file

1.3.2 (2021-04-16)

  • Restore the experimental high-level interface

1.3.1 (2021-04-16)

  • Fix the recommended version

1.3.0 (2021-04-09)

  • ECC-1231: Remove the experimental high-level interface

  • Added the “findlibs” module

  • Fix tests/ when MEMFS enabled

  • ECC-1226: Python3 bindings: Typo causes AttributeError when calling codes_index_get_double

1.2.0 (2021-03-23)

  • Added test for multi-field GRIBs

  • Fix deprecation warning: np.float is a deprecated alias for the builtin float

  • Experimental feature: grib_nearest_find

1.1.0 (2021-01-20)

  • ECC-1171: Performance: Python bindings: remove assert statements

  • ECC-1161: Python3 bindings: Do not raise exception on first failed attempt

  • ECC-1176: Python3 bindings: float32 recognised as int instead of float

  • GitHub pull request #41: Remove the apparent support for Python 2

  • GitHub pull request #44: Fix CFFI crash on windows

  • GitHub pull request #42: Add unit testing with GitHub actions (linux, macos and windows)

1.0.0 (2020-10-14)

  • ECC-1143: CMake: Migration to ecbuild v3.4

  • ECC-1133: C API: Propagate const char* for codes_index_new_from_file and codes_index_select_string

0.9.9 (2020-08-04)

  • Support for ecmwflibs. An additional way to find ECMWF libraries (if available)

  • ECC-1140: Segfault from invalid pointer reference in grib_set_double_array()

0.9.8 (2020-06-26)

  • ECC-1110: Removed obsolete function codes_close_file()

  • Provide missing argument to exceptions

  • Fix codes_set_definitions_path() typo

  • Fix grib_get_double_element(). Missing last argument

  • Add more tests to increase coverage

  • GitHub pull request #15: Add .__next__() method to eccodes.CodesFile class

  • ECC-1113: Python3 bindings under Windows: codes_get_long_array returns incorrect values

  • ECC-1108: Python3 bindings under Windows: use of handle causes crash

  • ECC-1121: Segfault when closing GribFile if messages are closed manually

0.9.6 (2020-03-10)

  • Update Copyright notices

  • Function-argument type checks: Improve error message

  • Fix C function calls for codes_gribex_mode_on/codes_gribex_mode_off

0.9.5 (2020-01-15)

  • ECC-1029: Function-argument type-checking should be disabled by default.

    To enable these checks, export ECCODES_PYTHON_ENABLE_TYPE_CHECKS=1

  • ECC-1032: Added codes_samples_path() and codes_definition_path()

  • ECC-1042: Python3 interface writes integer arrays incorrectly

  • ECC-794: Python3 interface: Expose the grib_get_data function

0.9.4 (2019-11-27)

  • Added new function: codes_get_version_info

  • ECC-753: Expose the codes_grib_nearest_find_multiple function in Python

  • ECC-1007: Python3 interface for eccodes cannot write large arrays

0.9.3 (2019-10-04)

  • New exception added: FunctionalityNotEnabledError

  • BUFR decoding: support for multi-element constant arrays (ECC-428)

0.9.2 (2019-07-09)

  • All ecCodes tests now pass

  • Simplify the xx_new_from_file calls

  • Fix for grib_set_string_array

  • Use ECCODES_DIR to locate the library

  • Remove the new-style high-level interface. It is still available in cfgrib.

0.9.1 (2019-06-06)

  • codes_get_long_array and codes_get_double_array now return a np.ndarray. See: #3.

0.9.0 (2019-05-07)

  • Declare the project as Beta.

0.8.0 (2019-04-08)

  • First public release.

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