How to extend spawnmob limit in minecraft?

Go to your server files, and there should be a folder called "plugins". Open that and then open the folder called "Essentials". Next, double click the file config.yml (you might need to right click it and then open it with notepad or another program). If you need a program, install notepad. After you open it, scroll down a bit until you find this -->

# Mob limit on the /spawnmob command per execution.
spawnmob-limit: 10

Replace 10 with the number you desire, such as 1000 or 15000. Make sure you keep a space between the: and the number. Just save it and then start up the server and it should work! If you server is on, just turn it off and back on to make this in effect.

Good luck Depends what platform you are playing on.

Depends what platform you are playing on.