A trigger is the event or condition that starts something automatically: an email sequence, a CRM update, a Slack alert, or a tracking tag firing on your website. Nothing happens in an automation until its trigger is met, so the trigger defines both when it runs and, just as importantly, when it does not.
How triggers work
The word is used in two closely related settings.
Workflow and marketing automation
In tools such as Zapier, Make, HubSpot, Mailchimp or Klaviyo, automations follow a “trigger, then action” pattern. The trigger might be a new form submission, a new row in a spreadsheet, a tag added to a contact, an abandoned basket or a date such as a renewal anniversary. When the trigger fires, the actions follow: send an email, create a deal, notify a colleague. Triggers often arrive through a webhook, where one system tells another the moment something happens, or by polling, where the tool checks for changes every few minutes.
Google Tag Manager
In Google Tag Manager, a trigger tells a tag when to fire. Built-in types include page views, clicks, form submissions, scroll depth, element visibility and custom events pushed from the data layer. Each trigger can carry conditions, for example “only clicks on links containing tel:” or “only on the /thank-you/ page”. A GA4 event tag paired with the right trigger records an enquiry; paired with the wrong one, it records nothing, or records every page view as an enquiry.
Why it matters
Most automation and tracking problems are trigger problems. A welcome email that goes out twice, a sales alert for spam submissions, a conversion counted every time someone reloads a thank-you page: in each case the action was fine and the trigger was too broad, too narrow or duplicated.
For UK websites there is a legal dimension. Under PECR, setting non-essential cookies or similar technologies on a visitor’s device needs consent. In Tag Manager that means triggers for analytics and advertising tags must respect the visitor’s choice in your cookie banner: either the tags wait for a consent event, or they use Consent Mode with additional consent checks so they only store cookies once permission is given. The Data (Use and Access) Act 2025 relaxed the rules for some low-risk uses, such as certain analytics, but at the time of writing (October 2026) check the ICO’s current guidance before relying on that, and advertising and remarketing tags still need consent. A trigger set to “All Pages” that fires a Meta pixel before the banner is answered is a compliance problem as well as a tracking one.
Common mistakes
- Using a form submission trigger on a form that never truly submits Such as one that sends by JavaScript, so nothing is recorded.
- Firing conversions on page view of a thank-you page that people can bookmark, reload or reach directly.
- Overlapping triggers in automation tools, so a contact who matches two conditions gets two sequences.
- No exclusions for internal staff, test submissions or existing customers.
- Marketing tags triggered before consent Or a consent setup that blocks the banner’s own script.
How to act on it
List every automation and every tag that matters to you, and write next to each one, in a sentence, what should trigger it and what should not. Then test each one as a visitor would: submit the form, decline cookies, accept cookies, reload the thank-you page. In Tag Manager, Preview mode and Tag Assistant show exactly which triggers fired on each action.
Where you can, base conversions on a confirmed event, such as a successful form response or a completed order, rather than a page view. Getting triggers and consent right is the groundwork for every paid campaign I run in performance marketing, because bidding on broken conversion data wastes budget.