What travels between steps is a list of items. Knowing how items move explains why a step ran three times, why a path did not run, and why an email went out once per row.

The rules

  • The trigger gives one item. A webhook's call, a form's answers, a schedule's time, a new row in a sheet.
  • Each step runs once for every item that reaches it, and gives one item back for each. Ten items in, the email is sent ten times.
  • Some steps give several items from one. Get rows gives one item per row, Split Out one per value in a list, Search emails one per email.
  • Some give fewer. Filter drops items that do not match; a Switch set to drop unmatched items drops them; Find rows that finds nothing gives none from that item.
  • A step that gets no items does not run, and nothing after it on that path runs either. That is not a failure.
  • A few steps run once for all their items together: Sort, Respond to Webhook, and Code set to Once for all items.

Paths

  • IF sends each item down Yes or No. Both paths can run in one run, each with its own items.
  • Switch sends each item down the first path whose rule it meets, or Everything else.
  • A path no item reached is not run at all. On a test, the line shows how many items went along it — 3 items — once the step before has finished.
  • Merge waits for every path that ran, then carries on with what they brought. See Bring paths back together with Merge.
  • Loop Over Items runs the steps on its Once per item path once per item or batch, then carries on down Done. See Repeat steps for each item with Loop Over Items.

Reading values item by item

  • {{ $json.… }} reads the item the step is working on.
  • {{ steps.key.… }} reads what that earlier step gave for this item — the one it came from — not always the first.

See Using what earlier steps found.

Good to know

  • Steps run top to bottom, one path at a time — Yes before No, a Switch's paths in their order.
  • Files travel with their item until a step drops them.
  • One turn of a run can take at most 10,000 steps, loops included. Past that it stops with More than 10,000 steps ran in one go, so the run was stopped. Look for a loop over far more items than expected.
  • A single step has 60 seconds — 10 minutes for steps that carry files — and a run has 15 minutes between Waits.

If something goes wrong

What you see Why What to do
A step ran many more times than expected A step before it gave several items — rows, emails, values. Check the earlier step's Output. Use Give them as: One list on Get rows, or a Filter, if you wanted one run of the step.
A step never ran, and the run succeeded No item reached it — a condition sent them all the other way, or a step gave none. Open the run and check the step before it.
A failure that starts Item 3 of 10: The step failed on one of several items. Check that item on the step's Input tab.