SlickGPT is a lightweight web-based client that provides access to multiple large language models from different providers, including OpenAI (GPT-4o, GPT-4o-mini, GPT-4, GPT-3.5), Groq (Llama3-8b, Llama3-70b), and Mistral (Mistral Large). It offers two usage modes: a free plan where users bring their own API keys and pay providers directly per use, and a Pro subscription (€5.99/month) that includes access to all models without needing an API key, with a fixed monthly price. Features include vision support for OpenAI models, optional user registration, and a clean chat interface.