Free
CSVKit
Open SourceCSV · Data Formats
Suite of command-line utilities for converting to and working with CSV.
csvclidata
Browse the complete directory — use filters to narrow down.
CSV · Data Formats
Suite of command-line utilities for converting to and working with CSV.
Generators · CSS Tools
Visual editor for CSS easing curves.
CLI Tools · Development Environment
The classic command-line tool for transferring data with URLs.
E2E & Browser · Testing
Developer-friendly browser-based E2E testing framework.
Data Viz & Charts · Frontend
The foundational data visualization library — direct SVG/DOM manipulation for fully custom visuals.
Pipelines & ETL · Data & Analytics
Modern data orchestrator with strong typing, testing and lineage.
UI Libraries · Frontend
Tailwind CSS component library with semantic class names.
Programming Languages
Official Dart language site with docs, packages and samples.
SQL Tools
Online SQL playground for testing and sharing queries across engines.
GUI Clients · Database
Free universal database GUI client supporting most engines.
GUI Clients · Database
Open-source database manager for SQL and NoSQL with web and desktop apps.
Pipelines & ETL · Data & Analytics
Analytics engineering: SQL-based transformation workflows with tests.
Regex
Regex tester with railway diagram visualization for PCRE, Python and JS.
Models & LLM APIs · AI for Developers
AI research lab with strong open-weight reasoning models and API.
Frameworks · Backend
Secure-by-default JavaScript/TypeScript runtime with built-in tooling.
Communities · Documentation & Learning
Community where developers write articles and share knowledge.
References · Documentation & Learning
Fast, offline-capable API documentation browser combining 100+ references.
Cheatsheets · Documentation & Learning
Rico's cheatsheets: concise cheatsheets for dozens of tools and languages.
Offline Toolkits · Developer Utilities
The developer swiss-army knife for Windows and macOS — JSON formatting, base64, JWT, regex and 30+ tools, fully offline.
Illustrations & Assets · Design & Prototyping
Avatar generator with 30+ styles — deterministic avatars from any seed via library, API or playground.
Agent & LLM Frameworks · AI for Developers
Open-source LLM app platform: agents, workflows and RAG (trending).
Markdown · PDF & Documents
Online Markdown editor with live preview and cloud sync.
Headless CMS · Backend
Open-source data platform that wraps any SQL database with APIs.
Frameworks · Backend
Batteries-included Python web framework with admin and ORM.