In testing code that uses the SendGrid Email Activity API, I have received "too many messages" errors. I have examined the "rate limit" response headers and it appears that I am being limited to 10 requests per 5 minute block in the day. That is, the first 5 minutes of every hour can have 10 requests, the next 5 minutes can have 10 requests, etc.
I asked SendGrid support about this. The first response was pretty generic, but seems to indicate that the threshold is correct and says I really should be using webhooks to get the status. I haven't found anything in the documentation saying this and I haven't seen anything the specifies what the rate limits are.
For those of you using the Email Activity API, are you limited to 10 requests per 5 minutes? If yes, what do you do with the API?