What constrains your application.
MEMORY LIMIT
How much memory one script may use.
Exceeded: a fatal error naming the limit.
MAXIMUM EXECUTION TIME
How long a script may run.
Exceeded: the request stops, frequently with a blank page or a timeout.
UPLOAD FILE SIZE
The largest single file that may be uploaded.
POST MAX SIZE
The largest total submission, including all files in one upload.
Must be larger than the upload file size, or uploads fail confusingly.
MAX INPUT VARS
How many form fields may be submitted.
Exceeded: settings silently fail to save, particularly in page builders and large menus.
That last one causes genuinely confusing problems.
WHERE TO SEE THEM
cPanel, PHP selector, options.
WHAT TO DO ABOUT THEM
Raise only what an application actually requires, and only as much as needed.
Limits exist to prevent one script consuming everything.
