How to Check That Your OTP SMS and Emails Actually Arrive (Synthetic Monitoring in CI)
Your uptime monitor says the login API returned 200. Your SMS provider's dashboard says "sent". And yet users can't log in, because the verification code never showed up. That gap is common and hard to see: an expired sender ID, a template that started landing in spam, a carrier quietly filtering a route, a provider incident where the API keeps returning success. Delivery receipts help, but they…
Uptime monitors report success but users still can't log in due to issues with OTP SMS and emails not arriving. Delivery receipts come from the same system being tested, so synthetic monitoring is needed. Trigger a real OTP send to a controlled phone or email on a schedule and measure arrival time. Get an API key via POST request, then send a check request to get a check ID and target.
Trigger your app's OTP send to the target and poll until the status is "received" or timed out. Fail the CI job if timed out. Email checks are free and unlimited, with SMS checks costing €29/month for a dedicated number. Synthetic checks only verify one test number or inbox, not provider delivery receipts or large-scale monitoring.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
