The perfect parser can be written in any language.
Imagine two situations:
1. Instant one-time data acquisition from a third-party resource
Suppose a user has inserted a link to a picture in a message. It is logical on the client side to download this picture and display it in the same message, and transfer base64 to the server, for example.
2. Pumping out a spherical horse in vacuum
Suppose you need to collect an unlimited amount of information for one task. In this case, I would create a queue in RabbitMQ and put a list of tasks there. The list of tasks can be formed on the client side. Next, the queue can parse several scripts that will download and parse data. It does not matter what language they are written. Yes, let it be even the client js of the user of your personal blog. The main thing is that it would be effective. Avoid situations where the user can close the browser after 98 hours of parsing a second before successful completion :)