# Triggers: cron, webhook, email & manual

> The four ways a workflow starts, and when to use each.

Source: https://cotera.co/docs/guides/workflows/triggers

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A trigger is what starts a workflow. There are four kinds, and most workflows graduate through them: manual while you build, then a schedule, a webhook, or an address for real.

## 1. Manual

Run the workflow yourself from the editor, with input you type in. This is the build-and-debug mode: run, inspect the run detail, adjust, repeat. Keep a workflow manual until its runs stop surprising you.

## 2. Schedule (cron)

Runs at fixed times. Presets cover hourly, daily, and weekly; a cron expression covers everything else (`0 9 * * 1-5` is weekdays at 9:00). Check the timezone shown on the trigger card. Best for digest-shaped work: summarize, report, sweep, sync.

![](https://cotera.co/media/docs/deploy/deploy-schedule-picker.png)

Full guide: [Run on a schedule](https://cotera.co/docs/deploy/run-on-a-schedule.md).

## 3. Webhook (from an app)

Runs when another system sends an event. Pick the app the events come from, with per-event filtering, or use a Custom webhook for any HTTP endpoint. The event payload becomes the workflow's input. Best for react-shaped work: enrich the new signup, triage the new ticket, respond to the payment.

Full guide: [Kick off from a webhook](https://cotera.co/docs/deploy/kick-off-from-a-webhook.md).

## 4. Email

Runs when mail arrives at an address Cotera mints for the trigger, like `deals-k3f9x2@inbound.cotera.ai`. The normalized message (sender, subject, both bodies, attachment names, auth results) becomes the workflow's input. Best when the person starting the work is outside your systems: a customer, a vendor, a candidate. Also the quickest way to wire up a source you have no webhook for, by pointing an inbox rule at the address.

Full guide: [Email your agent](https://cotera.co/docs/deploy/email-your-agent.md).

## Choosing

Ask one question: does the work follow the clock, or follow an event?

1. Clock: use a schedule.
2. Event from a system you integrate with: use a webhook. It fires in seconds, while a schedule polls too late or too often.
3. Event from a person, not a system: use email. Nobody outside your org can call your API, but everybody can send mail.
4. Can't get an event out of the source system? Schedule a short-interval sweep as the fallback, or forward the notification mail it already sends you to an email trigger.