A creative toolbox featuring shadow, SVG, gradient, and background pattern generators, color. Open-source, fast, and made for builders.

Build and grow your app business The world's best apps use RevenueCat to power purchases, manage customer data, and grow revenue on iOS, Android, and the web.

We spend a lot of time advising startups. Though one-on-one advice will always be crucial, we thought it might help us scale Y Combinator if we could distill the most generalizable parts of this advice into a sort of playbook we could give YC and YC Fellowship companies. Then we thought we should just give it to everyone. This is meant for people new to the world of startups. Most of this will not be new to people who have read a lot of what YC partners have written—the goal is to get it into one place. There may be a part II on how to scale a startup later—this mostly covers how to start one.

Free day number and week number calculator. Calculate what day of the year it is, ISO 8601 week numbers, days between dates, and time zone-based calendars. Embeddable widgets available.

This tool allows users to add invisible watermarks to text generated by AI. It assists in identifying machine-written content to maintain authenticity and track digital assets across platforms.

All Shadcn offers templates, components, blocks & tools to help developers build their projects faster.

We spend a lot of time advising startups. Though one-on-one advice will always be crucial, we thought it might help us scale Y Combinator if we could distill the most generalizable parts of this advice into a sort of playbook we could give YC and YC Fellowship companies. Then we thought we should just give it to everyone. This is meant for people new to the world of startups. Most of this will not be new to people who have read a lot of what YC partners have written—the goal is to get it into one place. There may be a part II on how to scale a startup later—this mostly covers how to start one.

Free day number and week number calculator. Calculate what day of the year it is, ISO 8601 week numbers, days between dates, and time zone-based calendars. Embeddable widgets available.

This tool allows users to add invisible watermarks to text generated by AI. It assists in identifying machine-written content to maintain authenticity and track digital assets across platforms.

Create clear, compliant UK invoices fast. Built for freelancers, small teams, and limited companies.

NanthAI is a web app that integrates premium AI models with advanced document analysis & specialised search capabilities

Rick Rubin brings ancient wisdom to the modern age in The Way of Code, a meditation on the art and science of vibe coding. With Claude by Anthropic, the Grammy-award winning producer and author of The Creative Act turns philosophy into practice with artifacts that can be creatively modified with AI.