# Triggers and schedules > A workflow starts when something happens in an app, at the times you schedule, or when you start it. Each start is one run. Web page: https://docs.lodol.com/docs/concepts/triggers Every workflow has one way to start, and it's the first thing in the workflow. Choose it by asking what the automation is for: | If the goal is… | Start it with | Example | | --- | --- | --- | | Reacting when something happens | An [app trigger](#app-triggers) | "When a Stripe payment comes in…" | | Doing something at regular times | A [schedule](#schedules) | "Every Monday at 9:00, send the pipeline digest." | | Doing something once, when you decide | [Nothing: run it on demand](#on-demand) | "Build this month's report for Acme." | ## App triggers An app trigger starts a run each time an event happens in a connected app: a new payment in Stripe, a new message in a Slack channel, a new email in Gmail, a new response to a form. The run receives the event, and later steps read its fields. Most triggers take **filters** that narrow which events start a run. **New Stripe payment** can be limited to one payment status; **New Slack message** watches the channel you pick and can be limited to one person or a keyword. **New Stripe payment** runs when a payment is *created*, which includes checkouts still waiting for the customer to pay. To log only completed payments, set its status filter to `succeeded`. ### What a trigger hands to the run Each trigger delivers a fixed set of fields. New Stripe payment, for example, delivers the payment's `amount`, `currency`, `status`, `customer`, `description` and when it was `created`. A step can only use what the event carries: the Gmail trigger delivers an email's sender, recipients, subject, date and body, but not its attachments. To work with those, add Gmail's [Download attachments](https://docs.lodol.com/docs/integrations/gmail.md#download-attachments) step. Each app's page lists its triggers, with their filters and the fields each one delivers. These apps have triggers: - [Airparser](https://docs.lodol.com/docs/integrations/airparser.md) - [Airtable](https://docs.lodol.com/docs/integrations/airtable.md) - [Box](https://docs.lodol.com/docs/integrations/box.md) - [Calendly](https://docs.lodol.com/docs/integrations/calendly.md) - [Canva](https://docs.lodol.com/docs/integrations/canva.md) - [ClickUp](https://docs.lodol.com/docs/integrations/clickup.md) - [Coda](https://docs.lodol.com/docs/integrations/coda.md) - [Discord](https://docs.lodol.com/docs/integrations/discord.md) - [Dropbox](https://docs.lodol.com/docs/integrations/dropbox.md) - [Eventbrite](https://docs.lodol.com/docs/integrations/eventbrite.md) - [Fillout](https://docs.lodol.com/docs/integrations/fillout.md) - [GitHub](https://docs.lodol.com/docs/integrations/github.md) - [Gmail](https://docs.lodol.com/docs/integrations/gmail.md) - [Google Calendar](https://docs.lodol.com/docs/integrations/google-calendar.md) - [Google Docs](https://docs.lodol.com/docs/integrations/google-docs.md) - [Google Drive](https://docs.lodol.com/docs/integrations/google-drive.md) - [Google Sheets](https://docs.lodol.com/docs/integrations/google-sheets.md) - [Linear](https://docs.lodol.com/docs/integrations/linear.md) - [Mercury](https://docs.lodol.com/docs/integrations/mercury.md) - [Microsoft Outlook](https://docs.lodol.com/docs/integrations/microsoft-outlook.md) - [Notion](https://docs.lodol.com/docs/integrations/notion.md) - [PayPal](https://docs.lodol.com/docs/integrations/paypal.md) - [QuickBooks Online](https://docs.lodol.com/docs/integrations/quickbooks.md) - [Rackspace Email](https://docs.lodol.com/docs/integrations/rackspace-email.md) - [Rackspace Email Admin](https://docs.lodol.com/docs/integrations/rackspace-email-admin.md) - [Slack](https://docs.lodol.com/docs/integrations/slack.md) - [Stripe](https://docs.lodol.com/docs/integrations/stripe.md) - [Telegram](https://docs.lodol.com/docs/integrations/telegram.md) - [Todoist](https://docs.lodol.com/docs/integrations/todoist.md) - [Trello](https://docs.lodol.com/docs/integrations/trello.md) - [Twitch](https://docs.lodol.com/docs/integrations/twitch.md) - [X (Twitter)](https://docs.lodol.com/docs/integrations/twitter.md) - [Zoom](https://docs.lodol.com/docs/integrations/zoom.md) For any other app, a [schedule](#schedules) can check for new records instead. ## Schedules A schedule starts a run at the times you choose. There are three kinds: - **Every few minutes, hours or days**, such as every 15 minutes. The shortest interval is one minute. - **At a time of day, on the days you choose**: every day at 8:00, every Monday, Wednesday and Friday at 17:30, or on the first of each month. - **Once**, at a date and time you set. Times follow the workflow owner's time zone unless you choose another one. ### Choosing between a trigger and a schedule If the goal is "when something happens", use the app's trigger. A schedule that checks for new records every hour does the same work up to an hour late, and has to work out which records it already handled. Use a schedule when the goal really is about time, like a weekly digest or a daily check, and keep two things in mind: - **Look back exactly one interval.** A daily run that reports on "yesterday" sees every day once. A run that only happens on weekdays never sees Saturday or Sunday, so look back to the last working day, or run every day. - **Don't overlap windows.** A daily run asking for "everything changed since yesterday" can see the same record on two days. End each window where the next run's begins. ## On demand A workflow with no trigger and no schedule runs only when something starts it: - **you**, from the workflow in Lodol - **your code**, through the [developer API](https://docs.lodol.com/docs/api/runs.md#run-a-workflow) - **another workflow**, with a [Run a workflow](https://docs.lodol.com/docs/guides/sub-workflows.md) step - **an AI agent**, which can use the workflow as one of its [tools](https://docs.lodol.com/docs/guides/ai-agents.md#tools) On-demand workflows can declare [inputs](https://docs.lodol.com/docs/concepts/inputs-and-outputs.md), such as which client to report on, so one workflow can be run for any of them. A workflow with a trigger or a schedule takes no inputs: everything it needs comes from the event or from its steps. ## Turning a workflow on A workflow with a trigger or a schedule runs only while it's turned on. Once it's on, each event, or each scheduled time, starts one run, until you turn it off or delete it. A workflow waiting for its trigger doesn't use any of your plan's runs. Saving a change to a workflow that's on pauses it until you turn it back on. ## Next