SimpleCache

SimpleCache is the PSR-16 Simple Cache interface defined by the PHP Framework Interop Group (PHP-FIG). It provides a lightweight, language-agnostic contract for a cache that can be implemented by a variety of backends, from in-memory arrays to external stores such as APCu, Memcached, Redis, or filesystem-based caches. The goal is to enable developers to depend on a single, simple API rather than on a specific caching implementation.

The interface focuses on eight core operations: obtaining and storing values with optional time-to-live (TTL), deleting values, and performing batch operations. The key methods are get and set for single entries, has and delete for existence checks and removal, clear to reset the entire cache, and getMultiple, setMultiple, and deleteMultiple for bulk operations. TTL support is included in set and setMultiple, allowing entries to expire after a defined interval; the exact handling of TTL may vary between implementations, with some treating TTL of zero as no expiration.

SimpleCache is designed for ease of use and interoperability. It enables libraries and applications to swap backends with minimal code changes, provided the underlying backend adheres to the PSR-16 contract. It is complementary to the more feature-rich PSR-6 (Cache) standard, which defines a more complex item pool model. In practice, developers choose SimpleCache for straightforward caching needs where a minimal, portable API is preferred, while recognizing that advanced caching scenarios may require a different or more capable interface.

Common implementations are provided by various PHP libraries and framework components and can back in-memory caches for single-request performance or persistent caches shared across requests and processes.