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.

The Core Tools is your curated gateway to essential productivity software and AI-powered tools that simplify, accelerate, and elevate your daily workflow. Focused on utility and performance, our platform features a handpicked collection of tools across a wide range of categories—from task management and automation to design, SEO, e-commerce, education, and more. Whether you're building a startup, managing a team, or working solo, The Core Tools helps you discover reliable solutions that actually get things done. Browse featured tools, explore by need or category, and find powerful apps that fit right into your stack. Got something great? Submit your own tool and connect with a growing audience of professionals who value clarity, efficiency, and results. No fluff. Just core tools that work.

The Core Tools is your curated gateway to essential productivity software and AI-powered tools that simplify, accelerate, and elevate your daily workflow. Focused on utility and performance, our platform features a handpicked collection of tools across a wide range of categories—from task management and automation to design, SEO, e-commerce, education, and more. Whether you're building a startup, managing a team, or working solo, The Core Tools helps you discover reliable solutions that actually get things done. Browse featured tools, explore by need or category, and find powerful apps that fit right into your stack. Got something great? Submit your own tool and connect with a growing audience of professionals who value clarity, efficiency, and results. No fluff. Just core tools that work.