How do you detect infinite loops in workflows?

An infinite loop in email automation is one of those problems that feels fine right up until it isn't. One contact enters a flow, triggers an action that re-enrolls them, and suddenly they've received 47 emails in four hours. By the time you notice, the damage to your sender reputation is already done.

Here's how to catch it before that happens.

Watch your volume numbers in real time. The clearest early warning sign is a sudden spike in sends from a single automation. Set a threshold for what "normal" looks like for each flow (say, 200 sends per day for a welcome series) and create an alert that fires when that number doubles unexpectedly. Most platforms like Klaviyo, ActiveCampaign, and HubSpot have built-in notification settings or webhook options you can wire up to Slack or email.

Track how many times each contact enters a flow. A contact entering the same automation three times in a week is a red flag. Most platforms let you set re-enrollment rules. If yours doesn't, you can often use a custom field as a counter and add a branch condition that exits anyone who's hit a limit (3 entries, for example). If someone hits that limit in less than 24 hours, investigate immediately.

Map how your automations connect to each other. Loops often don't live inside a single flow. They emerge at the edges, where one automation's exit action ("add to list X") is another flow's entry trigger ("enrolled when added to list X"). Draw this out. Literally. A whiteboard sketch of your flows and their triggers will reveal circular paths that aren't obvious inside the platform's UI.

Build safeguards directly into your flows. Don't rely on catching loops after the fact. Set hard limits like "exit after N emails sent" or "cannot re-enter for X days" as standard practice, not an afterthought. Unique event IDs or custom timestamp fields can also prevent the same event from triggering a flow twice.

Test for loops during QA, not in production. Before you launch any new automation, deliberately try to create the loop condition. Enroll a test contact, trigger the exit action manually, and see if they re-enter. If your safeguards hold, you're good. If they re-enter, fix it before the flow goes live.

If you're already seeing signs of a loop right now, pause the automation first, then investigate. The fastest way to stop the bleeding is to halt the flow entirely while you trace the path. You can always re-enable it once you've confirmed the circular trigger is broken.

Not sure whether what you're seeing is a loop or just a surge in legitimate activity? We're happy to take a look. Our SOS hotline is free and no-pitch.