A system can detect a hundred changes and still have nothing useful to interrupt a person about.
The first notification-design question is what decision the alert enables. The second is whether the person asked to receive it. Both should be answered before selecting an email provider.
Write the action in plain language
A hypothetical competitor tracker might report a meaningful price change on a watched app. The message should identify the app, the observed change, its date and the source to inspect. Internal job names and retry instructions belong in an operator’s console.
If the change is too ambiguous to explain without a paragraph of caveats, consider including it in a digest rather than interrupting immediately.
Give people a useful dial
Offer understandable frequency choices and an easy way to turn delivery off. Keep in-app notifications and email preferences distinct where the product supports both.
Do not treat an account email address as blanket permission for every marketing or operational message. A transactional alert should match the preference and workflow that created it.
Plan for retries
Notification delivery crosses systems. A timeout can mean the provider never accepted the message or accepted it before the response was lost. Use durable delivery records and provider-supported idempotency rather than blindly sending again.
Deduplicate repeated observations too. A source refreshed five times should not necessarily produce five alerts about the same event.
Finally, inspect the quiet cases: no change, stale source, revoked consent and an account that has been deleted. Correct behavior often means sending nothing.
Measure whether alerts lead to a useful action and whether people keep them enabled. An impressive delivery count can be a poor product outcome.
Attention is part of the cost your app imposes. Spend it on information that arrives with a clear reason and a reasonable next step.