FSSPEC: Filesystem interfaces for Python

Filesystem Spec (FSSPEC) is a project to unify various projects and classes to work with remote filesystems and file-system-like abstractions using a standard pythonic interface.


  • based on s3fs and gcsfs

  • fsspec instances are serializable and can be passed between processes/machines

  • the OpenFiles file-like instances are also serializable

  • implementations provide random access, to enable only the part of a file required to be read; plus a template to base other file-like classes on

  • file access can use transparent compression and text-mode

  • any file-system directory can be viewed as a key-value/mapping store

  • if installed, all file-system classes also subclass from pyarrow.filesystem.FileSystem, so can work with any arrow function expecting such an instance

  • writes can be transactional: stored in a temporary location and only moved to the final destination when the transaction is committed

  • FUSE: mount any path from any backend to a point on your file-system

  • cached instances tokenised on the instance parameters

These are described further in the Features of fsspec section.


pip install fsspec

Not all included filesystems are usable by default without installing extra dependencies. For example to be able to access data in S3:

pip install fsspec[s3]


conda install -c conda-forge fsspec


This repo contains several file-system implementations, see Built-in Implementations. However, the external projects s3fs and gcsfs depend on fsspec and share the same behaviours. Dask and Intake use fsspec internally for their IO needs.

The current list of known implementations can be found as follows

from fsspec.registry import known_implementations


These are only imported on request, which may fail if a required dependency is missing. The dictionary fsspec.registry contains all imported implementations, and can be mutated by user code, if necessary.

Indices and tables