Can someone please help me understand the information on this page? It says that I can use 250 quota units per second and that receiving one email "costs" 5 quota units. Does that mean that I can receive 50 emails per second? Or per day? Because at the top of the page it mentions "The Gmail API is subject to a daily usage limit"
https://developers.google.com/gmail/api/reference/quota
>Solution :
In the past, that page had an extra row that says the daily limit is one billion per day. Removing that line implies Gmail now has a dynamic daily limit (i.e., some users may get a higher/lower limit depending on their access pattern), but that per-second limit stays. So you can still get 50 emails per second, but excessive use along with other APIs might get you limited before the day ended.