Postscript is an SMS-marketing tool for Shopify stores. Connect it to an OptiMonk campaign and every phone number your popup collects grows your Postscript subscriber list automatically.

Before you start:

  • Postscript has to be installed in your Shopify store.

  • Your campaign's popup has to be built and it has to collect a phone number — the field mapping is read from the input fields of your popup, so without a phone field there is nothing to send. If your popup doesn't have one yet, ask the agent in the design chat for it ("add a phone number field") and let the popup rebuild.

Step 1 — Copy your Postscript Legacy API key

  1. Log in to your Postscript account.

  2. Click your website's name, then select API.

  3. Copy the characters next to Legacy API Key.

Keep the tab open — you also want to know which Keyword your new subscribers should land in. You find your keywords in Postscript under Acquisition.

Step 2 — Connect Postscript to your campaign

  1. Open Campaigns in the left menu and click the campaign you want to connect with Postscript.

  2. Open the Integrations tab of the campaign.

  3. Click Add integration. If this is your first one, the same step is offered as Connect your email or SMS tool.

  4. Provider step: pick Postscript. If the list is long, type into the Search providers… box. Accounts you have already connected are listed at the top, under Your connected accounts.

  5. Account step: click Connect a new account, paste the Legacy API key into the credential field, and give the connection a Name (optional) if you want to recognise it later. Click Connect.

    If the key is wrong, the wizard says so instead of saving: Connection failed — check the credentials.

  6. List step: pick where new subscribers should land in Postscript, then click Continue. Use Search lists… if you have many entries.

  7. Field mapping step: map the popup's Phone number field to Postscript's phone field — in Postscript that identifier is usually phone. Everything you don't want to forward stays on Don't sync. Click Save integration.

That's it. From now on, anyone who submits a phone number through your popup becomes a Postscript subscriber.


Draft vs. live: if the campaign has not been published yet, the integration shows a Draft pill and the note Saved as draft — it goes live when you publish the campaign. On a published campaign it is applied right away and shows as Active.

Field mapping

The mapping table has two columns: Popup field on the left (every input your popup collects) and Postscript field on the right. OptiMonk pre-fills the mapping with its own suggestions, so in most cases you only need to check it.

  • The phone number row is the important one — this is what makes the subscriber.

  • Pick Don't sync for any popup field you don't want to send.

  • If Postscript does not return a selectable field list, the right-hand side is a text box and the wizard tells you what to do: Type the exact Postscript field or property name (e.g. first_name). Leave empty to skip a field. Type phone there.

Change or remove the integration

The Integrations tab lists every integration on the campaign.

  • Change list reopens the wizard so you can pick another destination or redo the mapping.

  • Remove takes the integration off this campaign: Remove from this campaign? The account connection stays and can be added again. Your Postscript key is not deleted, so you can reuse the connection on another campaign.

Check that leads actually arrive

Open Leads in the left menu. Every submission has a Sync status column:

  • Synced — the subscriber reached Postscript.

  • Integration issue — the forwarding failed. Click the row to see the reason (Incorrect API key, Invalid list, Field mapping issue, Invalid phone number, Already unsubscribed…) and press Retry after you fixed the settings.