With the proposed solution every consumer will have a persistent connection to the server irrespective of the frequency of events. This setup seems inefficient unless you have a very high volume of events coming in. Many CDN networks have a limit on how long a connection you can open. And data providers will not prefer serving persistent requests.

Problems listed are signatures, dedup, buffering, bootstrap, cron. Everything other than signatures and bootstrap, can be solved by having a counter in every webhook payload. It will increment each time. When you receive a webhook and the counter does not match, the consumer can fetch the missing data from the events API.

I agree with the author that providers simply saying "at least once delivery" is insufficient. they should have solutions that does not require an architecture diagram.

Bootstrap is better served with a bulk events API so you don't make one call per request. It can have an after/cursor pagination. Solutions that work for our internal Kafka might not be suited to work across services, over the internet.