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.

Power Up Tools is your daily productivity boost in digital form. Built for doers, makers, and curious minds, our platform curates practical, powerful AI and SaaS tools that help you get more done—faster. Whether you're launching, writing, designing, selling, or just exploring what’s possible, we connect you to solutions that save time, simplify tasks, and spark creativity. Browse by category or dive into our featured tools to uncover hidden gems and emerging favorites. Power Up Tools isn’t just about discovery—it’s about momentum. Submit your tool to reach an audience that values efficiency, innovation, and getting things done. Every click brings you closer to smarter workflows.

Power Up Tools is your daily productivity boost in digital form. Built for doers, makers, and curious minds, our platform curates practical, powerful AI and SaaS tools that help you get more done—faster. Whether you're launching, writing, designing, selling, or just exploring what’s possible, we connect you to solutions that save time, simplify tasks, and spark creativity. Browse by category or dive into our featured tools to uncover hidden gems and emerging favorites. Power Up Tools isn’t just about discovery—it’s about momentum. Submit your tool to reach an audience that values efficiency, innovation, and getting things done. Every click brings you closer to smarter workflows.