Open-source alternatives to Onion

Gumbo-parser is a high-performance HTML5 parsing library written in pure C99. It transforms raw markup into a structured document tree by implementing the formal state-machine tokenization and error recovery rules defined in the HTML5 specification. The project serves as an HTML source mapping tool, linking parsed nodes back to their original byte offsets and pointers within the input buffer. This allows for the precise tracking of source locations for elements within the resulting parse tree. Beyond full document processing, the library handles isolated HTML fragments and provides a C-based

nanomsg is a distributed messaging middleware and scalable messaging library designed for moving data between machines and processes. It functions as a socket-based communication framework that routes data across different network transport layers. The library implements scalable messaging patterns, specifically request-reply and publish-subscribe, to handle high volumes of data across distributed systems. It provides tools for network performance benchmarking to quantify messaging throughput and latency. The framework supports distributed message routing and inter-process communication usin

Wrapper library for the BSD sockets API with a nicer C99 interface

s2n is a C-based security library and TLS protocol implementation that serves as a secure network transport layer. It provides a modular cryptographic backend interface to encrypt data streams, manage handshakes, and handle mutual authentication between peers. The project focuses on post-quantum cryptography, integrating quantum-resistant key exchange and digital signatures to protect connections against future computing threats. It distinguishes itself through security hardening measures, such as memory-locked secret storage to prevent keys from being swapped to disk and timing-attack mitiga

🚀Gev is a lightweight, fast non-blocking TCP network library / websocket server based on Reactor mode. Support custom protocols to quickly and easily build high-performance servers.

Master Server framework for Unity

AndroidNetworking is an HTTP networking library for Android that handles the full lifecycle of network communication, from sending requests to parsing responses and caching data. It provides a unified interface for executing GET, POST, PUT, DELETE, HEAD, and PATCH requests, with support for both synchronous and asynchronous execution, and includes built-in JSON response parsing that converts server responses directly into Java objects or lists. The library distinguishes itself through a set of integrated capabilities that go beyond basic request execution. It manages file downloads and upload

The CompCert formally-verified C compiler

RabbitMQ C client

Smaller, easier, more powerful, and more reliable than make. An implementation of djb's redo.

sds is a C dynamic string library that provides a memory management wrapper for heap-allocated strings. It implements binary-safe storage by tracking string lengths explicitly, allowing the library to handle null characters within data. The library distinguishes itself through a memory architecture that uses interchangeable function pointers for allocation and freeing, enabling the integration of custom memory managers. It utilizes header-stored length tracking to provide constant-time length retrieval and maintains null-terminated buffer padding to ensure compatibility with standard C string

Alamofire is an HTTP networking library that provides a foundation for managing network requests and responses through a chainable, type-safe interface. It serves as an asynchronous request manager, coordinating concurrent network operations and data streams while maintaining application responsiveness. The library distinguishes itself through a protocol-oriented request adaptation system, which utilizes interceptors to modify or authenticate requests before dispatch. It employs a middleware-driven pipeline to process traffic, handling encoding, authentication, and error recovery in a modular

AppImageKit is a system of tools and utilities for bundling Linux desktop applications into single-file, portable executables. It functions as a packager that converts application directories into self-mounting binaries, allowing software to run across multiple Linux distributions without a formal installation process. The project enables portable software distribution by isolating application configurations and home directories from the host system, which allows applications to run from removable media. It includes a filesystem manager for extracting, inspecting, and mounting the embedded im

GNU/Linux packaging made easy! ™

Reachability.swift is a network connectivity listener and Swift network state wrapper. It monitors real-time changes to network status and tracks whether a device is connected to Wi-Fi or cellular data. The library functions as a network reachability monitor that uses closures and system notifications to trigger callbacks when connectivity changes. It tracks internet connectivity and connection types to allow for network state handling and the adjustment of app content loading based on availability.

This is a non-blocking network client for Java applications that provides asynchronous HTTP request capabilities and bidirectional WebSocket connectivity. It leverages a Netty-based architecture to handle high volumes of network input and output. The library utilizes native transport abstractions such as Epoll, KQueue, and io_uring to reduce system latency. It supports HTTP/2 multiplexing to run multiple concurrent request-response streams over a single connection and provides automatic response body decompression for various formats. Core capabilities cover the management of complex network

klib is a comprehensive C standard library extension and data structure toolkit. It provides a set of fundamental tools for memory management, data organization, and general-purpose utility functions for standalone C applications. The project features specialized capabilities for bioinformatics sequence analysis, including the parsing of FASTA, FASTQ, and Newick formats and the implementation of Smith-Waterman sequence alignment and Hidden Markov Models. It also includes a mathematical computation library for numerical routines and expression evaluation, as well as a lightweight HTTP and FTP

WHATWG-compliant and fast URL parser written in modern C++, part of Internet Archive, Node.js, Clickhouse, Redpanda, Kong, Telegram, Adguard, Datadog and Cloudflare Workers.

A C library for statistical and scientific computing