In the code, if you look, I actually extend that rate limit to 5000 by using authenticated requests (on the client side, I know, this is "dangerous"). The problem is that it just takes a long long time, lots of request (~400 for Facebook alone), which gradually slow down as the browser gets overloaded.
the error message is:
{ "message": "API Rate Limit Exceeded for 112.199.99.5" }