The step that holds the events which start a flow; adding triggers, channel scope, how triggers interrupt one another, and the setup mistakes that keep a flow from ever running.
The most commonly forgotten part of an automation is not the message but the event that starts it: the flow is built perfectly and never runs, because the "when" was left empty. The Start step answers exactly that question. This guide covers every field inside it, how triggers relate to one another, and the setup mistakes that stop a flow from ever firing.
What it does
The Start step is the door to your flow. It is labelled When… and lists the events that set this automation going. When an event lands in the queue, the panel looks at the Start step of every published flow; if something matches, it opens a run.
Every flow has exactly one Start step. It cannot be deleted or duplicated; when you create a new automation it is the only box on the canvas. It has no input (the flow begins there anyway) and a single output, Then.
Adding and removing triggers
Tap the Start box on the canvas.
Tap Add trigger in the settings panel.
Pick the event from the list: Keyword, Any message, Default reply, Post comment, Mention, Story reply, Story mention, Post share, Link / ad or Date and time.
Fill in the fields that belong to that type (the keyword list, the post picker, and so on).
To start on a second kind of event as well, tap Add trigger again.
To remove one, tap Remove next to its row. A flow holds at most 20 triggers; in practice more than three or four makes it hard to keep track of when the automation actually runs.
Each trigger type has its own settings and rules; they are covered one by one in What a trigger is.
The Channel field
Every trigger has a Channel selector underneath it. The default is All channels: whichever connected channel the event arrives on, this flow starts.
Pick a specific channel and the trigger only works there. That is useful when the same keyword should get different answers on Instagram and WhatsApp: add two triggers and set one to each channel.
⚠️ Note: Post comment, mention, story reply, story mention and post share events only ever come from Instagram. On a WhatsApp account those types are not shown at all; if an older flow still holds one, the pre-publish check warns that the automation will never fire.
How triggers interrupt one another
What happens when a new event arrives while the person already has a run in progress depends on the trigger type.
Interrupting (explicit) triggers: keyword, post comment, mention, story reply, story mention, post share and link/ad. The person has arrived from somewhere new, so they are not left stranded mid-conversation: the running session is cut and the new flow starts.
Non-interrupting triggers: any message, default reply and date-and-time. These only run when the person is idle, that is when no run is in progress.
If you do not want a flow to be cut short, open the automation's Settings tab and turn off A new keyword can interrupt this automation. That is recommended for flows that collect data: when someone answers "what is your email?" with "price", the flow is not abandoned halfway.
Can the same person enter again
This setting lives on the automation's Settings tab rather than in the Start step, but it directly controls firing. It has four options:
Every time — the flow restarts whenever the event happens.
Once only — the person enters this flow once, ever.
Once a day — it fires once per day for the same person.
Once in a set period — you write your own period in hours.
"Once only" is right for campaigns and welcome flows; "every time" is right for support flows.
Its output and how to connect it
The Start step has one output, Then, and it must not be left empty. If it is, the pre-publish check raises the error Connect Start to a step and the automation cannot be published.
The first step is usually a Message, but it does not have to be: use a Condition if you want to split the path immediately, or an Action if you want to tag the person first.
Example
A hair salon wants one automation to handle both comments and DMs. It adds two triggers to the Start step:
Post comment — source Posts and reels, keywords price, booking. Whoever comments receives a private DM.
Keyword — keywords price, booking, match Contains. People who write straight to the DM land in the same flow.
Both are left on All channels, because only an Instagram account is connected. On the Settings tab, re-entry is set to Once a day: even if the same person comments on five posts, they get one message a day.
Common mistakes
Forgetting to add a trigger. The whole flow is ready but Start is empty. The pre-publish check raises Add at least one trigger, and that error blocks publishing.
Leaving a keyword trigger with no keywords. The type is chosen but the keyword box is empty. This also blocks publishing; add the words with Enter or a comma.
Adding Default reply twice. The second row has no effect at all; it is shown as a warning.
Putting the same word in both the match list and the excluded list of a comment trigger. The trigger can never fire, and the check warns about it.
Choosing a post that was deleted or has comments turned off. The post ID is still there but the event never arrives. The check says the post was not found, or that comments are off.
Narrowing the channel and forgetting about it. The trigger is set to WhatsApp while only Instagram is connected. The flow never fires and nothing looks broken.
Not choosing a field on the date-and-time trigger. When the mode is By a date on the contact, the flow cannot run until a date field is picked; that is another error that blocks publishing.
Related concepts
Every trigger type and its settings are covered in What a trigger is. For the step you will usually put right after Start, see The Message step. If the flow is built but never runs, My automation never starts walks through the checks in order.
A Start step set up correctly is what lets the rest of the flow work without you touching it again.