> I don't think they do, our whole job as an API company is to have uptime (and redundancy for uptime). I think it's the same with every other API company, such as Sendgrid, Twilio and etc.

That doesn't sound realistic to me. Sendgrid, Twilio, and all other APIs have downtimes and other problems, just check their status page: https://status.sendgrid.com/history.

I always had to implement some retry logic in API clients at some point or another. That doesn't mean your service doesn't bring value but it's not enough to just expect it to work because it is focused on uptime. When implementing a service that requires external dependencies I would always expect them to fail and try to design with that fact in mind.