PostPerfect is an AI tool that integrates with Twitter to improve and enhance your tweets, allowing you to customize your tweet style in a casual, serious, or even Jack Sparrow tone, with a dark mode option. It operates within your browser and suggests tweet improvements that you can easily remove with a one-click option, and is designed to have a lightweight and efficient user experience. It is available for purchase at a promotional price of $9 and will soon increase to $19, and does not require entering an OpenAI API key to use.