How do you spell Proxy in a plural form?

The letter “y” at the end of a Word often determines how the plural is formed:

If “y” follows a consonant → change y to ies.

Example: proxy → proxies, party → parties.

If “y” follows a vowel → simply add s.

Example: key → keys, toy → toys.

Would you like me to also explain why “proxy” becomes “proxies” specifically?