Free
Color Tools
Color blindness simulator: upload an image and preview eight vision types.
color-blindnessaccessibilitysimulator
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Color Tools
Color blindness simulator: upload an image and preview eight vision types.
Relational · Database
Distributed, PostgreSQL-compatible SQL database built for resilience.
Other Formats · Data Formats
Large collection of online formatters, validators and converters.
Practice & Challenges · Documentation & Learning
Community-driven coding kata platform across many languages.
AI Coding Assistants · AI for Developers
OpenAI's open-source coding agent for your terminal.
Color Tools
Collection of color tools: converter, palette, gradient and contrast.
Color Tools
Curated, community-voted color palettes.
Color Tools
Simple online color picker with HEX, RGB and HSL outputs.
Agent & LLM Frameworks · AI for Developers
Node-graph UI for Stable Diffusion and other generative models.
Hooks & Commits · Git & Version Control
Lint commit messages against Conventional Commits rules.
AI Coding Assistants · AI for Developers
Open-source AI code assistant you can point at any model.
Hooks & Commits · Git & Version Control
Specification for structured, human and machine-readable commit messages.
Serverless & BaaS · Database
Reactive backend platform with a realtime TypeScript database.
Self-Hosted PaaS · Cloud Platforms
Open-source, self-hosted Heroku/Netlify alternative.
Stock & Placeholders · Image & Media
Beautiful free stock videos for websites — curated clips optimized for hero sections and backgrounds.
Web Scraping · Data & Analytics
TypeScript web scraping and browser-automation library from Apify — anti-blocking and queue management included.
Full-stack Boilerplates · Project Starters
Scaffold a typesafe full-stack Next.js app in seconds — tRPC, Prisma/Drizzle, NextAuth and Tailwind wired together.
Agent & LLM Frameworks · AI for Developers
Framework for role-playing, autonomous AI agent teams.
Time & Cron · Developer Utilities
Quick editor and plain-English explainer for cron schedule expressions.
SSL & TLS · Security
Search certificate transparency logs for any domain.
Headers & CSP · Security
Google's tool to evaluate and debug Content Security Policies.
Generators · CSS Tools
Visual generator for CSS gradients with ready-made code.
Minifiers · Developer Utilities
Free online CSS minifier with API access.
Learning & Reference · CSS Tools
Long-running CSS and frontend resource with guides and snippets.