Open-source alternatives to Caffeine

Redis is a high-performance in-memory key-value store that functions as a distributed cache, message broker, and NoSQL database. It provides sub-millisecond read and write access to data stored in RAM and can operate as a vector database for indexing high-dimensional embeddings. The system supports a wide range of data storage and synchronization primitives, including the management of strings, hashes, lists, sets, and JSON documents. It enables real-time data operations through atomic transactions, hybrid persistence using snapshots and append-only logs, and high-availability configurations

Guava is a Java standard library extension and utility toolkit that provides optimized data structures, concurrency tools, and core extensions. It serves as a comprehensive set of helpers for Java development, focusing on reducing repetitive boilerplate logic. The project is distinguished by its specialized implementations of immutable collections, which ensure thread safety and data consistency by preventing accidental modification. It also includes a dedicated graph data structure library for modeling and traversing networks of interconnected nodes and edges, alongside advanced collection t

Quarkus is a Kubernetes-native Java framework designed for building high-performance, memory-efficient applications. It utilizes ahead-of-time native compilation to transform Java code into standalone, optimized binaries that eliminate the need for a virtual machine, enabling rapid startup and reduced memory consumption. By performing code augmentation during the build phase, it shifts heavy processing tasks away from runtime, ensuring that applications are optimized for cloud-native environments. The framework distinguishes itself through a unified approach to reactive and imperative program

Excelize is a library for reading and writing spreadsheet files in the Office Open XML format. It provides a comprehensive suite of tools for programmatically creating, modifying, and analyzing workbooks, worksheets, and cell data, ensuring compatibility across various office software suites through structured XML serialization. The library distinguishes itself with a built-in formula calculation engine that evaluates complex mathematical and logical expressions directly against workbook data. It also features a memory-mapped streaming architecture, which allows for the efficient processing o

This project is a native Windows port of the Redis in-memory key-value store. It provides a high-speed database that maintains datasets in RAM while using periodic snapshots to disk for data persistence. The implementation includes a background system service wrapper, allowing the data store to be installed as a Windows service that starts automatically upon computer boot. It utilizes native Windows compilation to enable execution directly on the host operating system. The system covers in-memory data caching and local data persistence, ensuring that information is recovered after a process

Cinder is a high-performance Python runtime implementation based on CPython. It is designed as an execution environment optimized for large-scale distributed systems and cloud environments. The project integrates a distributed memory cache and an asynchronous memory layer to manage data across multiple network nodes. It also provides a native C extension framework for developing high-performance compiled modules that link directly into the interpreter memory space. The system covers capabilities for asynchronous data retrieval, large-scale execution, and the integration of embedded scripting

Bigcache is a thread-safe, in-memory key-value store for Go designed to minimize garbage collection pauses. It functions as a memory-optimized cache capable of storing gigabytes of data while maintaining low latency during high-volume operations. The system avoids garbage collection overhead by managing memory through large byte arrays and manual allocation. It utilizes a circular-buffer layout to reuse space and lock-striped sharding to reduce contention during concurrent read and write access. The project provides capabilities for high-volume in-memory caching and low-latency data retrieva

This project is a feature-rich Go client library designed for interacting with Redis. It serves as a comprehensive interface for managing remote data stores, enabling developers to execute standard database commands, handle complex data structures, and perform asynchronous operations within Go applications. The library distinguishes itself through its support for advanced Redis capabilities, including connection pooling, pipelining, and transactional integrity. It provides specialized primitives for managing distributed clusters, including automated topology updates and request routing to sha

This repository serves as a comprehensive educational resource for mastering multi-threaded development and high-performance task coordination within the Java ecosystem. It provides technical guidance on implementing thread-safe data structures and synchronization primitives to ensure data integrity and prevent race conditions in complex applications. The material covers essential strategies for building scalable and fault-tolerant backend systems. It details the integration of asynchronous message queues for component decoupling, the application of circuit breakers to maintain service resili

This project is a comprehensive learning resource and reference guide for software architecture and distributed systems design. It serves as a structured curriculum for engineers to study fundamental architectural patterns, scalability strategies, and distributed computing theory, specifically tailored to prepare for technical interviews and professional engineering roles. The repository distinguishes itself by providing a curated collection of industry-standard infrastructure tools and methodologies. It covers the selection and implementation of technologies for data storage, message brokeri

This project is a comprehensive technical interview preparation resource and computer science interview guide. It serves as an educational reference for developers to study core software engineering fundamentals and common coding patterns required for employment screenings. The repository provides detailed guides and references covering data structures and algorithms, networking and security, operating systems, and web development. It specifically focuses on the implementation and complexity analysis of sorting, searching, and graph algorithms. The material encompasses a wide breadth of comp

SparkInternals is a technical reference and architecture guide detailing the internal design and implementation of the Apache Spark distributed computing engine. It serves as a study of big data engine analysis, focusing on how the system manages cluster execution and the interaction between driver nodes, executors, and workers. The project provides a detailed breakdown of how logical plans are converted into physical execution stages. It specifically analyzes the mechanics of data shuffle operations, memory management, and the coordination of distributed job scheduling. The documentation co

Pingora is a Rust-based framework for building high-performance network services, including HTTP reverse proxies, layer seven load balancers, and TLS termination proxies. It serves as an asynchronous network library designed to intercept and route HTTP, gRPC, and WebSocket traffic between clients and upstream backend servers. The project enables zero-downtime service updates by handing over listening sockets between processes during binary or configuration upgrades. It utilizes a programmable multi-phase pipeline to modify request and response bodies and headers, and it provides a pluggable T

Delightful on-disk cache (written in Swift)

This project is a comprehensive Java backend engineering guide and technical reference focused on high-concurrency design, distributed systems, and microservices architecture. It provides detailed strategies for decomposing monolithic applications, managing service discovery, and implementing the architectural patterns required for scalable backend environments. The repository distinguishes itself through an extensive collection of big data algorithmic references and database scaling strategies. It covers memory-efficient techniques for analyzing massive datasets, such as Top-K element extrac

FusionCache is a hybrid distributed caching library that coordinates local memory and distributed storage to balance access speed with global consistency. It functions as a resilient data access layer, utilizing a pluggable serialization framework to convert cached objects into various binary or text formats for compatibility across diverse storage environments. The system maintains cluster consistency through a distributed cache synchronizer that propagates invalidations and state updates across multiple nodes via a shared messaging backplane. It improves reliability by serving stale cache d

This project is a cross-platform development framework and managed runtime environment designed for building high-performance applications. It provides a comprehensive toolkit for constructing web services, cloud-native microservices, and desktop applications, utilizing a unified runtime that handles memory management and execution across diverse operating systems. The framework distinguishes itself through a native ahead-of-time compilation toolchain that transforms source code into optimized, self-contained machine code binaries. This capability enables fast startup times and reduced memory

Boto3 is the AWS SDK for Python, providing a programmatic interface for managing and automating AWS cloud infrastructure and services. It serves as a cloud management API client and resource manager for provisioning, configuring, and scaling virtual servers, databases, and storage. The library enables the implementation of infrastructure-as-code through declarative templates and scripts, allowing for the deployment of identical resource stacks across multiple accounts and geographic regions. It also provides a framework for coordinating distributed workflows, serverless functions, and contain

node-lru-cache is a key-value store for Node.js that implements a memory-limited cache. It prevents memory exhaustion by capping the total number of items or total byte size, automatically evicting the least-recently-used items to maintain these limits. The project provides specialized caching patterns, including time-to-live durations to ensure data freshness and a stale-while-revalidate mechanism that serves expired content while asynchronously fetching updates in the background. It also includes diagnostic tools for monitoring cache hits, misses, and eviction metrics through operational st

The AWS Cloud Development Kit is an infrastructure-as-code framework that enables developers to define and provision cloud resources using familiar programming languages. By utilizing construct-based synthesis, it translates high-level, object-oriented code into declarative templates, allowing for the automated management of complex cloud environments through a centralized, code-driven control plane. The framework distinguishes itself through its ability to model infrastructure as a dependency-aware resource graph, ensuring that components are provisioned and updated in the correct order. It

Spring PetClinic is a reference application for the Spring Framework, serving as a complete implementation that demonstrates the architecture and best practices for building Java services. It functions as a veterinary practice management system designed to track pet owners, animal records, and clinical visit histories. The project provides a practical example of a containerized web application, illustrating how to integrate a Java application with relational databases like MySQL and PostgreSQL. It serves as a guide for learning how to develop an application using the model-view-controller pat

Developer Roadmap is a community-driven platform that provides structured, graph-based learning paths for software engineering. It serves as a comprehensive knowledge repository where technical domains are organized into visual sequences to guide professional skill acquisition and career growth. The project distinguishes itself through a collaborative ecosystem that enables users to contribute roadmaps, curate industry best practices, and maintain professional profiles. It integrates diagnostic assessment frameworks to evaluate technical proficiency, helping developers identify knowledge gaps

Node-cache is a lightweight in-memory data storage module designed for Node.js applications. It functions as a key-value store that maintains frequently accessed data directly within the application runtime to improve response times and reduce latency. The library manages the lifecycle of stored information through automated expiration policies, which use internal timers to remove stale entries once a defined time-to-live duration has elapsed. It provides granular control over stored resources, allowing for the manual inspection, deletion, or clearing of specific keys to manage memory usage e

KeyDB is a multithreaded in-memory key-value store and distributed cache. It functions as a NoSQL database utilizing multi-version concurrency control to execute non-blocking queries and scans. The project is a multithreaded fork of Redis that maintains protocol compatibility while utilizing a multithreaded architecture to scale across multi-core hardware. It distinguishes itself with flash-tiered storage, allowing the system to offload data from primary RAM to SSD or flash storage to increase total capacity. The system supports high availability through active-active mesh replication and mu

DataFrame is a C++ tabular data library and manipulation engine designed for managing heterogeneous data in contiguous memory. It functions as a statistical analysis framework and time series analysis toolkit, providing the means to store, index, and transform multidimensional datasets. The project distinguishes itself through a high-performance execution model that utilizes column-major storage, SIMD-aligned memory allocation, and a thread-pool for parallel computations. It employs a visitor-based algorithm dispatch system and policy-driven transformations to decouple data processing logic f

Valkey is an in-memory, NoSQL database server designed for high-performance data storage and real-time state management. It operates as a distributed key-value store, maintaining datasets entirely within system memory to facilitate sub-millisecond response times for read and write operations. The system distinguishes itself through a single-threaded event loop that utilizes asynchronous I/O multiplexing to ensure high throughput. It supports high availability via master-replica replication and provides a decoupled communication model through a built-in publish-subscribe messaging pattern. To

NeDB is a JavaScript embedded NoSQL document store designed for Node.js and the browser. It functions as an in-memory data store with the option to persist documents to a local file system, ensuring data survives application restarts. The project utilizes a MongoDB-compatible API to perform data operations, allowing it to serve as a lightweight document indexing system and a persistent file database without requiring a separate database server. Capabilities include querying, inserting, updating, and deleting documents, as well as the ability to create indexes on specific fields to accelerate