How to Add AI Similar Product Recommendations to PDPs

Why put similar products on the product detail page

The product detail page (PDP) is where people usually decide whether to buy or go back. Putting a similar product recommendation block here lets you:

- Immediately surface a second-best option when the current product does not quite land
- For brands with many variants, easily show alternatives with similar size, color, or price points
- Keep users browsing within the PDP instead of sending them back to search or collections

These are the main benefits.

AI-based similar_products recommendations are especially useful because they can suggest “if you like this item, you might also like these” even for new visitors with little browsing history, and they tend to work more reliably than Shopify’s standard behavior-based widgets.

Prerequisites: environment assumed in this guide

• Your theme is published under Online store → Themes in the Shopify admin.
• You are using an Online Store 2.0 compatible theme that supports sections and app blocks.
• You have already installed a recommendation app such as RecoBoost from the Shopify App Store.
• RecoBoost provides recommendation blocks that support theme app extensions.

From here, using RecoBoost as an example, the steps below walk through configuring everything needed to place an AI similar products recommendation block on your PDPs. Other apps will follow almost the same flow, with only minor differences in screen names.

Steps: placing AI similar product recommendations on the PDP

• Open RecoBoost from the Shopify admin
  - In the left menu of the Shopify admin, go to Apps and click RecoBoost from the list.
• Create a recommendation logic in RecoBoost
  - In RecoBoost, open the Recommendation settings or Recommendation blocks screen.
  - Click the create-new button (for example Create recommendation) and choose AI similar products as the logic.
  - Give the block a clear name such as PDP-AI similar products and save it.
• Set product-level display conditions
  - On the same screen, set the display target to product pages only (enable any option that corresponds to hide on collection pages).
  - If needed, narrow down to the product group you want to show by using any collection filters or tag filters available.
• Configure storewide exclusion rules in RecoBoost
  - Open the Exclusion settings or Rules screen in RecoBoost.
  - Under products to exclude from recommendations, add rules based on product type or tags to exclude items such as gift cards and out-of-stock products.
  - If you want to exclude sale items, use any exclusion rules based on compare_at_price or tags.
• Open the Shopify theme editor
  - In the left menu of the Shopify admin, go to Online store → Themes.
  - Click Customize on your live theme to open the theme editor.
• Select the product page in the theme editor
  - In the dropdown at the top of the theme editor, choose Products, then select the template you want to edit, such as Default product.
• Add a theme app extension block
  - In the left-hand tree, select the product information section (for example Main product or Product template).
  - Click Add section or Add block and choose App block from the list.
  - Select the RecoBoost app block (for example RecoBoost recommendation).
• Link the app block to the AI similar products logic
  - Click the app block you just added to open the settings panel on the right.
  - From the recommendation type dropdown, select AI similar products or the PDP-AI similar products logic you created earlier.
  - Set the title to something that matches your store tone, such as Items similar to this one or Recommended similar items for you.
• Adjust the display position by dragging
  - Drag and drop the RecoBoost block within the left-hand tree.
  - As a rule of thumb, placing it directly under the product description or just before/after the reviews section works well.
• Check mobile preview and save
  - In the device selector at the top right of the theme editor, choose Mobile and make sure the AI similar products block does not become excessively long.
  - If everything looks fine, click Save to apply the changes.

Placement tips: where to put it, how many items, how many columns

• Place it right below the product description as the next move in comparison
  - After reading the description, users decide whether the product fits them. Showing similar products at that moment gives them alternative options the second they feel “this might not be quite right.”
• Test placing it before vs. after reviews
  - For products where reviews are a strong driver (cosmetics, electronics, etc.), placing similar products before the reviews can widen the comparison set.
  - For products with few reviews, placing it after the reviews can serve as a browsing hook to prevent drop-off near the bottom of the page.
• Start with 4–8 items
  - Set the Shopify theme to 2–4 columns and use a horizontal scroll (slider) layout.
  - Start with around 4–8 items so the scroll depth does not become too long, then adjust the number of items based on results.
• Avoid overlapping with “Frequently bought together” style widgets
  - If you show AI similar products, Frequently bought together, and Recently viewed all on the same PDP, you will scatter user attention.
  - Keep similar product recommendations to one block per page and clearly separate its position and title from other recommendation types.

Exclusion rules and validation: the minimum you should cover

• Exclusion rules: be explicit about what not to show
  - Gift cards and novelties: showing these as similar items can confuse the purchase experience, so exclude them in RecoBoost exclusion settings using product type or tags.
  - Out-of-stock or discontinued items: hide them in Shopify or, if RecoBoost has stock filters, enable show in-stock items only.
  - Mixing brands or lines: if you do not want to cross brands, restrict recommendations in RecoBoost to the same collection or same vendor.
• Initial metrics to watch: click-through rate and add-to-cart rate
  - If RecoBoost provides a Reports screen, check the click-through rate (CTR) and add-to-cart rate for each AI similar products block.
  - If both are low, consider whether the position is too low to be seen or the suggested products are not actually similar.
• Use Shopify reports to view trends at a session level
  - In the Shopify admin, go to Analytics → Reports and check product detail page performance and products viewed per session.
  - If products viewed per session increase after adding AI similar products, it is a sign that browsing depth has improved.
• A/B-test positions by switching every two weeks
  - In the theme editor, change the position of the AI similar products block as follows:
  - Pattern A: directly under the product description
  - Pattern B: directly after the reviews
  and compare CTR and add-to-cart rate in two-week intervals.
  - Once a clear winner emerges, make that position your provisional standard and roll it out to other product templates.

Next steps with RecoBoost

Once you have an AI similar products block on your PDPs, there are two next steps in RecoBoost that will make results easier to understand.

• Separate AI similar products from other logics under RecoBoost → Recommendation settings
  - Create separate recommendations for each use case, such as PDP-AI similar products for product details and recommendations before/after cart add.
  - Reviewing reports for each block separately lets you see which positions and which logics are actually performing.
• Check performance per block under RecoBoost → Reports
  - In the RecoBoost Reports screen, review impressions, clicks, and revenue contribution for the AI similar products block.
  - If certain product templates (for example apparel or bags) perform particularly well, prioritize rolling out the same pattern on the product detail pages for those categories.