Setting Up Postscript Onsite Opt-In (OOI) with Alia
Alia integrates directly with Postscript Onsite Opt-In (OOI) to create a faster, higher-converting SMS signup experience without sending shoppers off-site or requiring them to send a text message.
Instead of submitting a phone number and replying “Y” via SMS, shoppers receive a 4-digit verification code directly inside the popup. With a single tap, they’re opted in.
The result:
No keyword replies
No off-site friction
No compliance tradeoffs
Up to 3× more SMS subscribers
This guide is for Alia customers who have an active Postscript account and want to enable Onsite Opt-In (OOI). Once configured, everything can be managed directly inside Alia and Postscript without requiring manual setup assistance from the Alia team.
Before You Begin
Before you begin, make sure your Postscript is integrated to Alia. You will need to select a keyword during setup but the keyword will not actually be used once Onsite Opt-In (OOI) is enabled.
Onsite Opt-In (OOI) requires the Postscript SDK to be installed on your storefront. If it is not installed, you may see an error message preventing Onsite Opt-In (OOI) from functioning correctly.
You can install the SDK using Postscript’s developer documentation.
Set Up Onsite Opt-in in Alia
From the popup that you'd like to configure in Alia, navigate to the Phone Submission step.
2. Select the SMS submit button in the phone step.
3. Then navigate to Integration Settings, then Postscript Settings.
4. Enable “On-site opt in”
Important: Onsite Opt-In (OOI) is enabled per phone step, not globally across the popup
If your popup contains multiple phone collection steps, OOI must be enabled on each one individually
Set Your Welcome Message
Because Onsite Opt-In (OOI) removes keywords from the signup flow, your welcome message is now configured directly inside Alia.
From the SMS submit button settings, you’ll see a Welcome Text field.
A typical welcome message looks like:
Thanks for subscribing! Here’s your coupon for discount_amount off: discount_code Shop here: link_to_apply_discount
You can dynamically insert the following using Alia’s expression variables:
Discount amount
Discount code
Discount link
Important:
Do not use the {{ shop_name }} variable from Postscript templates
If migrating from an existing keyword-based flow, do not copy the preview/mock phone link shown inside Postscript. Instead, use the brand’s actual homepage URL when configuring links
Add the Verification Step
Onsite Opt-In (OOI) requires a verification step where shoppers enter their 4-digit code. To add it:
Select the + Add Step button.
Under Collection, select Verification. Place this step between the Phone stepand the View Code step
Your flow should look like:
Phone Step → Verification Step → View Code Step
Add a Branch for Existing Subscribers
If a shopper is already subscribed to SMS, they should skip the verification process entirely. On the Phone step:
Select the SMS submit button
Under When form is submitted, add a branch: If “Postscript user SMS already subscribed” → Go to “View Code” step
Updating Your Postscript Flows
With OOI enabled:
Keywords are completely removed from the opt-in process
Subscribers are instead attributed under Third-Party Onsite Opt-In
This means:
No Reply-Y flows
No keyword-triggered opt-ins
No keyword-based segmentation for Alia popup subscribers
Update Your Welcome Series & Automation Filters
If your current Postscript flows rely on any of the following, those filters must be updated:
keyword filters
popup keywords
Reply-Y logic
What Needs to Change
Anywhere you currently use:
“Keyword most recently triggered”
Reply-Y conditions
Keyword-based popup segmentation
you should remove those filters.
If you still want to specifically segment or identify Alia popup subscribers, we recommend adding a custom property on email/SMS submission and using that property for automation filtering instead.
Compliance Requirements
OOI introduces stricter compliance requirements that must be followed before publishing.
Required Compliance Rules
To remain compliant:
SMS consent text must appear above the submit button
Consent text must be clearly visible and sufficiently contrast against the background
Consent text must be at least 10px in size
Terms of Service and Privacy Policy links must:
Be bolded
Be UPPERCASE
Be underlined
Use a contrasting color from the surrounding consent text
Editing Compliance Styling
All compliance styling can be edited directly inside the Alia Popup Editor, including:
Consent text placement
Font size
Text color
Link styling
Terms & Privacy formatting
No custom code is required.
Here's the TCPA-approved compliance language:
*By providing your phone number, you agree to receive recurring automated marketing text messages (e.g. cart reminders) from this shop and third parties acting on its behalf. Consent is not a condition to obtain goods or services. Msg & data rates may apply. Msg frequency varies. Reply HELP for help and STOP to cancel. You also agree to the Terms of Service and Privacy Policy.
IMPORTANT: To help support compliant subscriber collection, your Terms of Service and Privacy Policy should be directly linked within the compliance language shown above.
Postscript recommends using hosted Dynamic Terms of Service and Messaging Privacy Policy links wherever SMS consent is collected, including popups, embedded forms, landing pages, and checkout opt-in experiences.
If hyperlinks cannot be used, include the full URLs for your messaging Terms of Service and Messaging Privacy Policy so visitors can access them directly.
For example: View our Terms of Service (https://myshop.com/terms-of-service/) and Privacy Policy (https://myshop.com/privacy-policy/).
Testing & Publishing
Test Your Popup
Before publishing:
Open the popup preview
Test the full OOI flow
Verify:
verification code functionality
existing subscriber logic
welcome message delivery
consent visibility
Publish or Mark as Ready
When publishing an OOI popup, Alia automatically runs compliance validations and screenshot checks.
This process includes:
Mobile & desktop screenshots
Consent visibility analysis
Compliance validation checks
Internal logging for audit purposes
If validation fails, you’ll be prompted to correct the issue before publishing.
Additional Setup Notes
Enable Opt-In Tracking
To properly track net SMS opt-ins:
Navigate to Settings
Enable “Show opt-ins”
Message Analytics
Analytics for the OOI welcome message live inside Postscript.
To view message analytics:
From your Postscript dashboard, navigate to Data & Insights
Select Messages and navigate to the Message Analytics tab
Here you can track:
Sends
Deliverability
Engagement
Revenue attribution
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