Perpend is a UI wrapper that allows for easy experimentation with OpenAI's GPT models. Key features and advantages of Perpend include:

NocoAI

AI Vercel Playground

Detect GPT

PromptSandbox

Promptmetheus

Promptitude.io
"Promptitude empowers SaaS and mobile app developers to create, test, manage, and improve GPT prompts seamlessly with one simple API call, regardless of the provider.\n\n**"

Commander GPT

MysticLabs AI

Prompt Attack

Helicone