How can I control server to client strings with single and double quotes?

I'm using PHP 8 & HTML5.
My browser is current Chrome.

The server creates a string, usually pulled from a database field:
{"Name":"The big Test","Str":"Johy's back yard has a sign that says "No Shouting". We're "NOT" SHOUTING!"}
This is valid JSON.

When I transfer it to the client the string changes. All the escape back slashes disappear.
{"Name":"The big Test","Str":"Johy's back yard has a sign that says "No peeing in the POOL!". We're "NOT" goa do it!"}
This is NOT valid...

How can I control server to client strings with single and double quotes?