Also seems like best practice would be to have SPF/etc. entries in place for multiple ESPs, even if you routinely just use one, and be able to switch, for just this reason.
Also seems like best practice would be to have SPF/etc. entries in place for multiple ESPs, even if you routinely just use one, and be able to switch, for just this reason.
What it means is that basically you should be using 2 providers at the same time and send 50%/50% on each provider in order to keep your IP warms.
While I think big services should account for such scenario, I think 95% of Sendgrid customers are using them to avoid setting up that kind of redundancy.
Main question is should I create the same redundancy for my hosting provider, DNS services, CDN etc...
Update: For some reason I couldn't reply to your response kstrauser so here is my reply: That works if and when their is trust. First you have trust the buyer isn't going to abuse the system and wreck the IP [reputation] and you have to trust the buyer isn't giving you stolen info. Obviously things one can work through but again, it involves trust. Also the provider has to have warmed up IPs to give out. Which, having warmed up IPs would actually be a great valued add upsell for those that need them!
Update 2: Thank you FfejL and symfoniq for explaining it better.
I'm not saying this to advertise but to offer a suggestion: call someone and ask for help. This isn't an unusual need at all and any reputable provider will be quick to help.
Short version: you don't have to "warm up an IP" if you do a little advance homework.
If Google (or any other ISP) suddenly sees an big spike in email from @example.com on an IP that @example.com hasn't used previously, Google is much more likely to mark those emails as Spam.
So senders need to 'warm up' an IP by sending a small amount of email first, usually for a few days at least.
So if you're a SendGrid customer expecting to send 2,000,000 emails today, you can't just switch to a new ESP and send those same emails. Spam rates will go through the roof.
DNS is interesting, especially if you do anything location-based. I currently use just CloudFlare, but am not convinced they have enough internal redundancy on DNS, so investigating using Dyn, or self hosting again, or Route53, or some combination. It gets a more complex if you want to use multiple providers doing anything beyond simple DNS though (the DNS protocol itself is totally fine for this, but most of the config management is provider-specific, and using normal dns zone transfers/notifies doesn't really work in this model)