Flysystem is a file storage abstraction library for PHP that provides a unified interface to interact with many types of filesystems.
The problem Flysystem solves is vendor lock-in and inconsistency when working with different storage backends. Rather than writing filesystem-specific code for local disks, cloud storage, or remote servers, developers write once against Flysystem's consistent API and can swap storage backends without changing application logic. The library achieves this through an adapter pattern, where each storage type implements a common interface.
Flysystem suits any PHP project that needs flexible file storage. It is particularly valuable for applications that might migrate between storage solutions or support multiple deployment environments with different storage requirements. The officially supported adapters cover common scenarios including local filesystems, FTP, SFTP, in-memory storage, AWS S3, Google Cloud Storage, MongoDB GridFS, WebDAV, and ZipArchive. Beyond these, a substantial ecosystem of third-party adapters extends support to Azure Blob Storage, Dropbox, OneDrive, Gitlab, and other services. For storage needs not covered by existing adapters, the library provides documentation for creating custom adapters.
The project maintains active development with regular updates and clear upgrade paths between major versions. Documentation is comprehensive, covering architecture, the public API, and migration guidance for users upgrading from earlier versions. The maintainers provide security contact information separate from the public issue tracker, indicating a structured approach to handling vulnerabilities.
