Small telegram web extension client

I would like to create a browser extension which will make a custom buttons on Gitlab pages. On click these buttons will send a message to telegram chat with content from page (parse html tags, page url and other). I want to make my work processes simply with this extension

I have an experience of make sites, and I can make an extension, but I dont know, how I can send messages to telegram in JS code authored me (not bot)

I cant found info about telegram REST API, only libs as Tdlib and other. I would like make and use something like web client, with authorization, select chat and message pattern in my extension popup, after it make a button on page – onclick send pattern message with parsed page data to selected chat

However I would like to do this without backend, only fronted extension code

If you have similar experience or you can write a plan of actions to realise my idea – please, write it here 🙂

Now I make a small extension which placed in Merge Request Page a button which put a pattern message with parsed page data to buffer

But I cant use it, because telegram dont parse markdown links on messages sended users so i cant paste message from buffer and press Enter – formatting dont work 🙁

I would like to make my extension so better, make function of right sending to telegram messages with customising patterns