# Journey monitoring

> Continuously monitor your critical journeys validated by email or SMS, from Datadog Synthetics or any monitoring tool.
> https://facteur.eu/en/product/monitoring

## Your tests stop at CI. Your critical journeys do not.

A signup journey that breaks in production almost never breaks at deploy time: it degrades on a Thursday evening, at a router, on one domain. The only way to know is to replay it continuously, verification code included.

## Monitoring is not testing

- **This address never changes** : A monitoring inbox lives for months: its address is declared in your monitor, in your synthetics tool, sometimes in an allow list on the sender side. It must not be recycled between runs like a CI inbox.
- **Capacity reserved for monitoring** : Your monitors must never be starved of quota by a load test running alongside. An inbox marked “monitoring” has its own reserve: even with the account exhausted, it keeps accepting. A monitoring tool that goes blind when CI runs away is worthless.
- **Reception latency is a metric** : Every message carries the delay between SMTP acceptance and availability through the API. That is what you monitor: an OTP taking forty seconds has not failed, but your signup journey is already broken for the user.
- **Read-only keys** : A monitor must not be able to create or delete anything. A key restricted to one inbox, read-only, with expiry and IP restriction, which limits the damage if it leaks into a synthetics configuration.
- **Performance mode** : For a monitor, all that matters is that the message arrived and how long it took. In performance mode we confirm reception, measure, and store nothing: no data lying around, and no retention cost.
- **The metric is yours** : Reception latency is published as a metric: you threshold it in the tool that already holds your on-call rota, and that tool decides who gets woken.

## What a monitored journey really checks

An HTTP check on your signup page tells you it responds. It does not tell you that a user can sign up.

- The monitor creates an account on your production environment, with a unique address in your monitoring inbox.
- It waits for the verification code. Our API blocks until it arrives, and measures the delay.
- It extracts the code, already isolated from the body, and completes the signup.
- It deletes the test account, and starts again in five minutes.

## From the tool you already use

There is nothing to install: a read-only key and an HTTP call that waits.