Developer Tools

ResponsiveTestTool previews websites at mobile, tablet, desktop, and TV screen sizes.

Tiny Helpers collects useful online utilities for building websites, and its project page notes that contributions are closed.

The SPDX License List provides standardized identifiers for commonly used software, data, hardware, and documentation licenses.

Brain.js provides GPU-accelerated neural networks in JavaScript for browsers and Node.js.

The Easing Functions Cheat Sheet helps users choose animation easing curves by showing how parameters change over time.

Website uptime monitoring with status pages, SSL checks and multi-region checks. Free for 10 monitors.

Free open-source desktop Git client for Windows, macOS and Linux, with a commit graph, branching, staging and diff views.

Free open-source Windows shell interface for Git, with Explorer status icons and context-menu access to commits, diffs and history.

A static documentation generator using Markdown pages and a YAML project configuration.

A Markdown-based book and documentation generator for material organized in chapter order.

A Ruby-focused online regular-expression editor for checking patterns against sample text.

LightTest compares website loading performance frame by frame on a shared timeline.

Build native user interfaces with Slint, an open-source declarative GUI toolkit for Rust, C++, JavaScript, and Python.

Accord.NET combines machine learning with audio and image processing libraries in a C# framework.

Real-time web log analysis and interactive reports are available through GoAccess.

Budibase helps teams build internal tools, automate workflows, and create AI agents connected to business systems.

Bytecode Viewer is a Java and Android APK reverse engineering suite with decompiling, editing, and debugging tools.

Open-source system monitoring with a time-series database and query language is provided by Prometheus.

DummyImage generates placeholder images with customizable dimensions and foreground and background colors.

electron-builder packages Electron applications for distribution and supports automatic updates.

The Luyten interface lets users decompile Java programs using Procyon.

SpeedVitals tests website speed from more than 30 locations and devices and reports Core Web Vitals.

LangChain’s reference docs cover packages for LangChain, LangGraph, agents, LangSmith, and integrations.

Can I Use provides browser support tables for HTML, CSS, and other web platform features.