You have to use Firebase to deliver messages to Android anyway, having it deliver to APNS as well you get for free with that implementation.
Maybe you do want to do those things, but this implementation doesn't, nor do they mention the intention to do that. But if you did, SNS also provides implementations for delivering SMS and Email (preferably through SES).
Startups shouldn't waste their money on this type of thing, especially if you consider most startups will fail. Vendor lock-in is a pretty stupid thing to worry about for an early-stage start-up (and I argue it's stupid to worry about long-term too if that vendor is AWS, Google or Azure who are all very competitive with each other).
Nothing in the article really said how they got to millions an hour. In my experience the notifications are cheap enough to send that that figure is easy to obtain without any special effort on the push side. It's also embarrassingly parallel/easy to scale. How everything else scales around that (recipient filtering, reporting) is the interesting part.
If you're really worried about lock-in, most event based PaaS support running containers. Moving between clouds would then just be the glue-work around your containers.
* SMS - You can't just interface directly with some cell company (which is proprietary anyways). * EMAIL - Have you tried to send your own emails in the past decade? Just use a provider. * Push Notifications - Have to use Firebase for Android anyways.
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Your core stuff should limit proprietary stuff. Edges are going to change over time no matter what, might as well use stuff that makes you faster now.
Wut? People don't even know anymore that you can use cellphones to send SMS?! (And no, that's not the only option, SS7 works just fine as well.)
> * EMAIL - Have you tried to send your own emails in the past decade? Just use a provider.
Have you? Talking nonsense does not make expertise ...
You might want to throttle messages based on user settings or say ML models to avoid too many annoying messages. For critical stuff you might want to switch over to email or SMS.
These are startups that have the funding to do this kind of thing. This is a core part of the stack for any such company.