Once your Shopify store is connected (see the Setup Guide above), the real value comes from choosing the right customer segment and campaign type — and setting it up so it targets the right people, at the right moment, without surprises on your bill. This guide walks through LettrLabs' built-in Shopify filter presets and how to put them to work in winback, retention, and retargeting campaigns, including how to measure results with a holdout group.
Built-in filter presets
Rather than building targeting logic from scratch, LettrLabs ships with ready-made Shopify presets grouped by goal. You can use any of these as-is or edit the underlying filters to match your own criteria:
Retention — Enhance First-Time Buyer Retention (target first-time customers to encourage a second order); Total Spent in Past Year (target customers above a spend threshold).
Winback — First-Time Buyer Winback (one order, 90–180 days ago); Lapsed 1st-Time Buyer Winback; VIP Winback by order count and time; VIP Winback by spend and time (customers with 2+ orders and $250+ spend who haven't ordered recently).
Retargeting — Target Customers in a Geographic Region; VIP Retargeting Cross-Sell (spend-based, product-specific); Retargeting High-AOV Multiple Purchases; Retarget Non-Discount Customers.
Underlying filters you can mix and match include order count, total spend, average order value, last order date, first purchase date, specific products purchased, discount usage, and location (state/city/zip). All of LettrLabs' Shopify automations are built off completed order data, so campaigns key off things like order count, spend, and timing rather than in-cart/browse behavior.
Winback: turning first-time buyers into repeat customers
Winning a second purchase is one of the highest-leverage moments in the customer lifecycle. A typical setup:
Start from the First-Time Buyer Winback preset (or build your own with Order Count = 1 and Last Order Date between 90 and 180 days ago) to target one-time buyers who are drifting but still re-engageable.
Choose a template — a handwritten card works well here since the personal, tangible touch tends to perform strongly for winback versus digital-only channels.
Add a personalized thank-you message and a time-sensitive offer (a discount code, free shipping, or gift) to give the recipient a clear reason to come back. If you use a discount code, you can track redemptions to tie the mailer directly to a conversion.
For higher-value customers who've already shown repeat behavior, use the VIP Winback presets instead (2+ orders, spend thresholds) — these are worth a more premium template and offer, since the lifetime value at stake is higher.
Retargeting: cross-selling with a holdout group
Retargeting campaigns are a strong fit for cross-selling a complementary product to recent buyers. A typical cross-sell setup:
Filter to recent buyers of Product A (e.g. purchased within the last 7–14 days), and exclude anyone who already owns Product B, so you're not pitching something they already have.
Design a card featuring the complementary product, a clear call to action, and — if you're using one — a unique promo code and QR code so you can track scans and redemptions back to the mailer.
Turn on Holdout Testing and set a holdout percentage between 25% and 50%. The holdout group is a random slice of otherwise-qualifying customers who are deliberately not mailed, so you have a clean comparison group.
Holdout Testing is available on Shopify, Klaviyo, and Lead Reveal automations. Because it withholds part of your qualifying audience from every send, plan your monthly send limit and budget with the holdout in mind — LettrLabs will prompt you to increase your sending limit if it's too low to produce a statistically meaningful holdout comparison.
Measuring lift from a holdout group
Once a holdout campaign has been running, compare conversion rates between the mailed group and the holdout group in your LettrLabs attribution/analytics reporting:
Mailed conversion rate = mailed orders ÷ mailed recipients
Holdout conversion rate = holdout orders ÷ holdout recipients
Incremental lift = mailed conversion rate − holdout conversion rate
Incremental orders = incremental lift × mailed recipients
Incremental revenue = incremental orders × average order value
For example: 7,500 mailed recipients converting at 10.5% versus 2,500 holdout recipients converting at 5.2% works out to roughly +5.3 points of incremental lift — meaning a meaningful share of those mailed orders likely wouldn't have happened without the mailer.
Best practices
Set a monthly send limit on every automation so postage spend stays predictable as your audience grows — this matters even more on holdout campaigns, since the holdout reduces how many qualifying customers actually get mailed.
Use Testing status before you scale. A newly saved automation starts out inactive rather than mailing immediately — use this window to confirm your filters are catching the right customers before switching it to Active.
Keep audience windows tight for retargeting (7–14 days) so purchase intent is still fresh, and widen the window if your audience looks too small.
Name automations by store and use case if you run multiple Shopify stores, so it's obvious at a glance what each one does.
Track redemptions with unique discount codes and QR codes so you can tie mailed pieces directly to Shopify checkout conversions.
Want help designing a template or defining your first segment? Reach out to our team — we're happy to help.