Langfa.st is a fast and minimal playground for testing and refining AI prompts. It supports over 50 large language models, including OpenAI, Anthropic, Mistral, Cohere, Google, and others — all available instantly without setup. You can insert variables, use Jinja2 templating, and compare outputs across models. There’s no need to sign up or bring your own API keys — it works out of the box. Langfa.st was built to eliminate the friction of existing tools: complicated UIs, required credentials, or overpriced subscriptions. It gives AI teams and prompt engineers a clean, disposable space to experiment, debug, and iterate — all in one tab. Free to use. You only pay if you need more volume or power features.

Langfa.st is a fast and minimal playground for testing and refining AI prompts. It supports over 50 large language models, including OpenAI, Anthropic, Mistral, Cohere, Google, and others — all available instantly without setup. You can insert variables, use Jinja2 templating, and compare outputs across models. There’s no need to sign up or bring your own API keys — it works out of the box. Langfa.st was built to eliminate the friction of existing tools: complicated UIs, required credentials, or overpriced subscriptions. It gives AI teams and prompt engineers a clean, disposable space to experiment, debug, and iterate — all in one tab. Free to use. You only pay if you need more volume or power features.

Tool Cosmos is a retro-themed universe of modern productivity software. Inspired by vintage computing but powered by today's most effective tools, it’s your terminal to explore hundreds of AI-powered apps, utilities, and solutions across dozens of categories—from automation and marketing to image editing and customer support. Whether you're building something big or just optimizing your workflow, Tool Cosmos helps you discover tools that boost efficiency, creativity, and success. With featured tools, deep categories, and a unique vintage interface, Tool Cosmos blends nostalgia with innovation. Submit your own tool to connect with a growing tech-savvy audience and be part of a new era in classic software discovery.

Tool Cosmos is a retro-themed universe of modern productivity software. Inspired by vintage computing but powered by today's most effective tools, it’s your terminal to explore hundreds of AI-powered apps, utilities, and solutions across dozens of categories—from automation and marketing to image editing and customer support. Whether you're building something big or just optimizing your workflow, Tool Cosmos helps you discover tools that boost efficiency, creativity, and success. With featured tools, deep categories, and a unique vintage interface, Tool Cosmos blends nostalgia with innovation. Submit your own tool to connect with a growing tech-savvy audience and be part of a new era in classic software discovery.