mod that I've created causes lag whenever activated.

[Misjudgments]

so, I've created a mod that sends a request to the hypixel api: api.hypixel.net
and i created a condition that on every 15 seconds worth of ticks it will send a request to fetch a certain data of all the players in the lobby
when it works, it causes a lag that freezes my minecraft client for about a second, then unfreezes the game and works perfectly until the next time it runs (after 15 seconds).

if anyone could help me understand why it is happening and how can i fix that i would be very grateful, thanks to all the readers and the responders.
(english is not my main language so if my post seems weird or offensive in any way please forgive me.)

[DePhoegon]

Umm I wouldn't know how to address this, but I will say it sounds like the network call isn't being done async style.  Like you're having the local instance call the for data that's so far away (in retrospect) 

you would need to look at what your doing, where you're calling it from, and what you're accomplishing with it.