What’s the difference between internal vs external event triggers?
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Your email platform knows a lot about what happens inside email. But it has no idea your customer just placed an order, upgraded their plan, or abandoned a cart. That's the core difference between internal and external event triggers.
Internal triggers fire from activity your ESP tracks directly. Things like an email open, a click, a form submission through your platform, a tag being added, or a subscriber moving to a new list segment. These happen inside the system, so the data is immediate and complete. No integration needed.
External triggers come from outside your ESP entirely. A purchase on your ecommerce store, a CRM field updating when a deal closes, a user hitting a milestone in your app, a support ticket being resolved. These require your ESP to receive data from another system, either through a direct integration, a webhook, or an API call.
The practical difference comes down to three things.
- Speed. Internal triggers are instant. External triggers depend on how fast the other system fires and whether the connection is healthy. A slight delay is normal. A broken integration means the trigger never fires at all.
- Data richness. Internal events carry full ESP context automatically. External events only bring what the sending system decides to include. If you want to personalize based on a purchase, the external system has to pass that order data along explicitly.
- Reliability. Internal events are handled entirely within one system. External events can fail silently if an API call drops or a webhook times out. (Worth having a plan for that.)
The best automations usually combine both. An external trigger kicks things off, say a purchase event from Klaviyo's Shopify integration or a deal stage change in HubSpot. Then internal triggers shape what happens next based on whether the subscriber opens, clicks, or ignores the first email.
For ecommerce especially, you almost always need external triggers to send anything meaningful. Your ESP doesn't know what someone bought. Your store does. Getting those systems talking to each other is usually the first automation challenge worth solving.
If you're figuring out how to connect your tools without writing custom code, the next question covers using Zapier or n8n to bridge your systems. Or if something is already broken mid-flow, our SOS hotline is free and we actually pick up.
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