hiredis vs redis: What are the differences?

Introduction

Hiredis is a minimalistic C client library for Redis while Redis is an open-source, in-memory data structure store used as a database, cache, and message broker. Both Hiredis and Redis are used for interacting with Redis servers, but there are key differences between them.

1. Efficiency: Hiredis is designed for high performance and efficiency as it is implemented in C. It uses a simple and lightweight API for communication with the Redis server. On the other hand, Redis is written in C and is highly optimized for speed and low memory usage. It provides various data structures and commands for manipulating data.

2. Abstraction Level: Hiredis provides a lower-level API that closely follows the Redis protocol. It offers basic operations like sending commands and receiving replies directly. Redis, on the other hand, provides a higher-level API along with built-in data structures like strings, lists, sets, hashes, and sorted sets. It supports more complex operations and features.

3. Asynchronous Support: Hiredis supports asynchronous I/O, allowing clients to perform operations in a non-blocking way. It provides functions for managing multiple connections and handling callbacks for I/O events. Redis, by default, operates synchronously and blocks the client until a reply is received. However, it does offer an asynchronous mode using the "Redis Cluster" feature.

4. Error Handling: Hiredis handles errors by returning error codes or NULL pointers when appropriate. It leaves the responsibility of error handling to the client application. Redis, on the other hand, utilizes a unified error reporting mechanism where errors are returned as part of the reply from the server. It provides detailed error messages along with the encountered command and arguments.

5. Compatibility: Hiredis is designed to be compatible with any C codebase and provides a single-header file for easy integration. It has no external dependencies other than the C standard library. Redis, being a separate server, supports clients in multiple languages including C, Python, Java, Ruby, and more. It provides client libraries and drivers specific to each language.

6. Additional Features: Hiredis focuses on simplicity and minimalism, providing only the essential functionality to communicate with a Redis server. Redis, being a complete database system, offers a wide range of features beyond simple key-value operations. It includes features like replication, persistence, Lua scripting, pub/sub messaging, and more.

In summary, Hiredis is a lightweight and efficient client library for Redis, providing a low-level API and asynchronous support. Redis, on the other hand, is a full-fledged in-memory data store with high-level APIs, built-in data structures, and additional features beyond basic Redis operations.