Summary: Every step in the Flow editor has a built-in test panel — Generate Sample Data — that runs the trigger or action for real, shows you the output, and saves it as sample data you can map into later steps.
Who this is for: Anyone building or editing Flows in Alta.
Why test your steps
Testing does two jobs at once:
It confirms the step actually works before you publish the Flow.
It generates sample data — the real output of the step — which powers the data selector in every step after it. Without sample data, you're mapping fields blind.
Before you start
The step's inputs must be valid. If the test button is grayed out, hover it — you'll see "Please fix inputs first", "Please wait until all inputs are loaded", or "Saving..." depending on what's blocking it.
Testing a trigger
Open your Flow and click the trigger step. The Generate Sample Data panel appears in the step settings.
What you see depends on the trigger type:
Event-based triggers show a Test Trigger button. Clicking it simulates the event. If the integration ships mock data, you'll also see a Use Mock Data option, so you can skip the live test.
Webhook triggers show a note — "Send Data to the webhook URL to generate sample data to use in the next steps" — plus a Generate Sample Data button that opens a test dialog. You can also just send a real request to the webhook URL.
Polling triggers (integrations that check for new records) show a Load Sample Data button. Alta fetches recent events and lists them in a dropdown as Result #1, Result #2, and so on — pick the one you want to use as sample data.
When the test finishes, you'll see Tested Successfully with a timestamp, and the output appears below.
Testing an action step
Click any action step in the canvas. The Generate Sample Data panel shows a Test Step button.
Click Test Step. The step runs for real with the sample data from earlier steps. While it runs you'll see Testing... (or Agent running... for Run Agent steps), and a Cancel button if you want to stop it.
When it completes, the panel shows Tested Successfully or Testing Failed, plus the result. To run it again after changing inputs, click Test.
Reading the results
The result viewer has up to three tabs: Input (what went into the step), Output (what came back), and Logs (console output, shown only when the step produced logs — useful for Code steps).
On a polling trigger, the note under the dropdown reminds you: "The sample data can be used in the next steps."
Tips and common pitfalls
Tests run for real. Testing a "Send Slack message" step sends an actual message. Point test steps at a safe target (a test channel, your own email) while building.
Error details disappear on refresh. If a test fails, the panel notes "Errors are not saved on refresh" — copy the error before reloading the page.
Stale poll results: if the dropdown shows "Old results were removed, retest for new sample data", the previously fetched events are gone — click the test button again to load fresh ones.
Changed a field mapping? Retest the step so downstream steps see the updated output shape.
Related
How to Build and Manage Flows in Alta (Workflows: Drafts, Publish, Runs)
How to trigger an Alta Flow with an incoming Webhook (Catch Webhook)
How to Trigger an Alta Flow from Alta Events (Prospect Replies, Status Changes, Calls, and More)