ChatGPT Telegram Bot on Cloudflare Workers

A minimal example of a Telegram Bot for ChatGPT running on a Cloudflare Worker.

Setup

Get your new bot token from @BotFather: https://core.telegram.org/bots#6-botfather
Get an OpenAI API key: https://platform.openai.com/account/api-keys
Sign up to Cloudflare Workers: https://workers.cloudflare.com/
In the Cloudflare Dashboard go to "Workers" and then click "Create a Service"
Choose a name and click "Create a Service" to create the worker
Click on "Quick Edit" to change the source code of your new worker
Copy and paste the code from bot.js into the editor
Replace the TOKEN variable in the code with your token from @BotFather
Replace the API_KEY variable in the code with your OpenAI API key
Optional: Change the WEBHOOK variable to a different path and the SECRET variable to a random secret. See https://core.telegram.org/bots/api#setwebhook
Click on "Save and Deploy"
In the middle panel append /registerWebhook to the url. For example: https://my-worker-123.username.workers.dev/registerWebhook
Click "Send". In the right panel should appear Ok. If 401 Unauthorized appears, you may have used a wrong bot token.
That's it, now you can send a ChatGPT prompt to your Telegram bot