Why is the VKontakte bot responding slowly and sending two messages each?

Question

PHP

Developed two bots on VKontakte: one parses the college page and sends a link to the schedule, the second one simply replies to messages (it can also respond with stickers, videos and photos). Both bots are written in PHP and hosted on Heroku.
Such a question: does the bot respond for a long time and / or two messages per request due to bad code or weak hosting?

Answer 1

How long, how long is that?
3-5 minutes? Seconds? Everyone has their own concept of long.
If you want to look at the server response time, take the message that VK sends you in json format, and insert it into Postman, for example, and request the bot address through it. This way you can get the approximate response time of your script to a message. Well, then, already optimization. Naturally, if you have hosting, and not VPS, then the speeds will not be so hot at all.
PS two messages each, most likely due to a timeout or error. Are you using Callback API?

Answer 2

If the cheapest Heroku is, then there Instances fall asleep and wake up when there is activity