> ## Documentation Index
> Fetch the complete documentation index at: https://docs.tallwatch.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Monitor dependencies

> Tell Tallwatch which monitors sit upstream so a shared outage doesn't page you for every downstream service at once.

When your database goes down, every service that depends on it fails too. Without dependencies, that's a dozen incidents and a dozen alerts for one root cause. Dependencies let you mark the upstream monitor so the downstream alerts stay quiet while the real problem is already paging you.

## How it works

On a monitor, set one or more other monitors as dependencies. When an incident opens for this monitor, Tallwatch checks its dependencies first. If any of them is currently `down`, the dispatch is suppressed: the incident is still recorded, but no alert goes out for it.

The suppressed dispatch is written to the record as `suppressed`, so the incident is fully auditable later. You see that it happened and why, you just don't get paged for it.

<Note>
  Dependencies gate alerting, not checking. The downstream monitor keeps running its checks and opening incidents. Only the notification is held back while an upstream monitor is down.
</Note>

## A typical setup

Say `API healthcheck` and `Web app` both depend on `Primary database`:

* The database goes down. Its monitor opens an incident and pages you.
* The API and web monitors fail too and open their own incidents. Because their dependency is down, those alerts are suppressed.
* You fix the database. It recovers, and so do the services that depend on it.

You get one alert about the cause instead of three about the symptoms.

## Choosing dependencies

Point a monitor at the things it genuinely can't work without: the database, the auth service, the upstream API. Don't chain dependencies speculatively. The goal is to silence symptom alerts during a shared outage, so only the relationships that actually cause correlated failures are worth encoding.