Which server is suitable for laravel app to handle 5k - 10k simultaneous visitors

What kind of server do you have right now? Do you struggle with performance?

Also where do you host your server right now?

A server with 4GB and 2CPU's should be able to handle this just fine, at least it does that for most of my websites. If you're not sure you can always take a tier higher

i have a server with 1CPU & 4GB ram it work's find until i reach 1500 simultaneous visitors it get down

i'm hosting my website on "OVH" company

i'm running my server on Ubuntu 16.04 using Nginx and MySQL

do you have any reference article on how to configure optimize the server ?

1500 is not that much and your server should be able to handle that kind of load.

One more CPU would nice though.

I suggest you add some throttling to your requests if you haven't already done that. Then you should check the number of requests generated by your elooquent. The fewer queries to the database for each request is better.

https://laravel.com/docs/5.8/routing#rate-limiting

https://laravel.com/docs/5.8/telescope

The number of simultaneous visitors is a pretty poor measure. What counts is the requests per second and the level of database contention.

A simultaneous visitor (eg has an active session) could load a page per hour, or a page every 10 seconds.

In some way you can calculate the amount you need

(number of CPU cores / Average Page Response Time in seconds) * 60 * User Click Frequency in seconds = Maximum simultaneous users

You can then calculate how much you need. However you need to gather some data first. It's really hard to tell you what server you need at this point. But upgrading one tier should never harm your server ;)