Open-Time Email Recommendations — Embed in Any ESP

Your email platform is great at sending. But what if the product recommendations inside each email updated themselves in real time — showing each recipient exactly what they’re most likely to buy, based on their most recent behavior, at the moment they open the email?

Watch the 1:27 walkthrough: picking an email template, how each product is rendered as an image, the fallback when there is nothing to show, and copying the code.

That’s what Personyze’s open-time email recommendations do. You drop one HTML snippet into your email template once, whichever email platform (ESP) you use. This guide walks through the campaign and then the embed for Mailchimp, Klaviyo, HubSpot, ActiveCampaign, Brevo and Constant Contact.

How open-time personalization works

A normal product block is baked in when the email is sent, so everyone gets the same thing. Here the snippet is only image tags. Every time someone opens the email, their email client asks Personyze for those images, and Personyze picks the products for that person at that moment.

1. Personyze learns from your site. Product views, add-to-carts and purchases, tied to a person once Personyze knows their email or your own ID for them.
2. Your ESP sends the email with the snippet in it. Your platform’s merge tag puts each recipient’s email (or ID) into the image addresses.
3. The recipient opens the email. Their email client requests the images from Personyze.
4. Personyze renders the images on the spot, from that person’s history and your catalog as it is now.

Create the campaign

New campaign → Email & SMS → Product Recs in 3rd-Party Emails. The wizard has eight steps:

There is no Target step: everyone the email goes to gets the widget, and the snippet decides per person what it shows.

Before you start

• A product catalog in Personyze. The New campaign card warns you when there is none.
• The Personyze tracking code on your site, so there is behaviour to personalize from. See Installing Personyze.
• Recipients Personyze can recognise. Their email, or your own user ID, has to be on their Personyze profile: captured on your site (a form, a login, or the JavaScript API) or sent through the server API. Anyone else gets the non-personal picks.
• An email template you can add HTML to, such as a Code, HTML or Custom Code block.

Step 1 — Catalog

Personyze keeps one product catalog per site, and email, on-site and JSON recommendations all read it. If it is not set up yet, do it in Settings → Recommendation setup → Product Catalog. There are five ways in:

Step 2 — Interactions

The personalized algorithms learn from what each person did on your site: products viewed, added to cart and purchased. The Interactions step shows whether each event is arriving, and the setup lives in Settings → Recommendation setup → Product Tracking. Most sites need no code there: store integrations, Google Tag Manager and on-page detection all work. Every route is on Product Interaction Tracking.

If you would rather send the events from your own code, these are the tracker commands:

window.personyze = window.personyze || [];
// on a product page
personyze.push(["Product Viewed", "12345"]);
// when that product is added to the cart
personyze.push(["Product Added to cart", "12345"]);
// on the order confirmation: everything in the cart was bought
personyze.push(["Products Purchased"]);

The ID is the product’s Internal ID in your catalog. An event whose ID is not in the catalog cannot be matched to a product. For a single item bought outside the cart, send ["Product Purchased", "12345"].

Step 3 — Look

Choose Browse template gallery and pick a design. You can then change colours, text and layout in the editor beside the preview. Each product is rendered as one image, so the design looks the same in every email client. The product layouts:

The gallery also has single-image formats for ads and social: Leaderboard Banner — 728×90, Square Social Tile — 320×320, Story Tile — 360×640 and a Price Drop Retargeting Card.

The first card in the editor, Image & link, has three settings:

• Generate image type: PNG (transparent) keeps rounded corners and sits cleanly on any email background, while JPEG makes smaller files.
• Link brings to: the item’s URL by default, or any other field in your catalog.
• If a link is broken, send them to: where a click lands when the item’s link cannot be reached.

Step 4 — Recommendation

This is where you choose the algorithm. The picker is the same one on-site widgets use, with one difference. An email is not opened on a page of your site, so the Page row offers what the recipient did instead:

The Type row groups the algorithms as it does for the web: Personalized & Behavioral; Cross-Sells, Co-Views & Upsells; Visitor History; Catalog Events; and Custom. What each one picks is on Recommendation Algorithms. Good starting points for email:

• Personalized Recommendations: picks from the recipient’s own browsing and purchases. Best for people who have visited your site.
• Recently Viewed, or Others Who Viewed Also Viewed on Items they viewed: browse-abandonment emails.
• Items in Cart, and Cross-Sells on Items in their cart: cart abandonment.
• Cross-Sells or Up-Sells on Items they purchased: post-purchase follow-ups. Use Buy it Again for products people reorder.
• Most Popular, Trending Now or Best Sellers: new subscribers, and anyone Personyze does not know yet.

When it comes back short

The Output card beside the algorithm decides how many items there are, and what happens when there are too few:

• Recommendations to show: how many items to ask for, up to 12. The Code step gives you one image slot per item.
• Fallback algorithms → Add fallback: more algorithms that run in order when the main one, and each fallback before them, returns too few items. Each fallback has its own filters. A common setup is Personalized Recommendations with Best Sellers as the fallback.
• Fill empty cells: when this is on, a short or empty result is topped up with your most popular items, then the rest of the catalog. When it is off, only what the recommendation actually returned is shown.

Below the Output card are the same filters and tuning as on-site widgets: Skip items the visitor already…, Restrict the catalog, Fine-tune the algorithm and Custom filter rules. See Filters and Fallbacks.

Non-personal recommendations

You can use this with no individual history at all:

• Anchor to a product. In the Code step, choose the Product internal ID tab and put a product ID in the snippet. Personyze then recommends as it would for someone who viewed that product, for example related items in an order confirmation.
• Site-wide picks. Most Popular, Trending Now or Best Sellers on General need no history for the person at all.

Step 5 — Code

The Code step builds the snippet in three choices:

1. The identifier. Email; Internal User ID, which is your own ID for the person and only works if you also send it to Personyze from your site or the server API; or Product internal ID, for non-personal picks.
2. Your email platform. Its merge tag is written into the snippet for you. Custom takes any tag you type.
3. Copy. Paste the snippet into your template once, where you want the products to appear.

What the snippet does

Each <img> address carries the recipient’s email (or ID). When the email is opened, Personyze:

1. looks up that person’s profile: what they viewed, added to cart and bought;
2. runs the algorithm you chose in Step 4;
3. checks your catalog as it is now, for price and stock;
4. renders each product as an image and returns it.

Each slot has its own key in its address (k=…v, k=…w and so on), so every slot shows a different item. If the template has a heading, a heading image goes above the row, and it disappears when there is nothing to show. A two-slot snippet with Mailchimp chosen looks like this:

<table border="0" cellpadding="0" cellspacing="0" role="presentation">
	<tr>
		<td align="center" valign="top">
			<a href="https://pic.personyze.com/href/k=8qy0zs2vbzcv/email=*|EMAIL|*">
				<img src="https://pic.personyze.com/png/k=8qy0zs2vbzcv/email=*|EMAIL|*" alt="Recommended" border="0" style="display:block; max-width:100%; height:auto;">
			</a>
		</td>
		<td align="center" valign="top">
			<a href="https://pic.personyze.com/href/k=8qy0zs2vbzcw/email=*|EMAIL|*">
				<img src="https://pic.personyze.com/png/k=8qy0zs2vbzcw/email=*|EMAIL|*" alt="Recommended" border="0" style="display:block; max-width:100%; height:auto;">
			</a>
		</td>
	</tr>
</table>

With Internal User ID the addresses end in internal_id= followed by your platform’s ID tag. With Product internal ID they end in item_internal_id={INSERT PRODUCT ID HERE}, and you put the product ID there yourself.

Insert it into your email platform

It is the same on every platform: add an HTML block to your template, paste the snippet, and make sure the recipient’s email is filled in by that platform’s merge tag. If you chose your platform in the Code step, the tag is already there.

Quick reference — email merge tags

The tags each platform documents for the recipient’s email address and for a recipient ID (used by the Internal User ID tab). For the ones marked “Code step”, choosing the platform there writes the tag into the snippet for you.

Step 6 — QA

Before sending to your list, the QA step shows the actual images a recipient would get. These are live renders, and they are not counted as views. Save the campaign first: the images come from the saved version, so unsaved edits do not show.

What to check before sending

• The picks look personal. For a known recipient they should relate to what that person viewed or bought. If they look generic, check that events are arriving (Step 2) and that the person’s email is on their profile.
• The fallback is acceptable. Preview a New recipient. An empty slot there is a result, not a broken image: the campaign had nothing to show. Add a fallback algorithm or turn on Fill empty cells (Step 4) if it should always fill.
• Send a real test from your ESP. Visual previews do not fill in merge tags. Open the test in a real inbox.
• Clicks land in the right place. Click each product in the test email and check it opens the right product page.

Step 7 — Automation

This step is optional. Add rules that email you, post to Slack, call a webhook or pause the campaign when its numbers cross a line you set. See Automation.

Step 8 — Performance

The Performance step shows Email Get Code statistics. Personyze does not send the email, so there is no Sent, bounce or unsubscribe figure. Counting starts when a recipient’s email client shows the widget.

Reading the numbers: Email, SMS, web push and 3rd-party emails on the Performance Metrics page explains every figure on this screen and how to read it.

Every metric card has a Users … link (Users viewed, Users clicked and so on). It opens the exact people behind the number, one row per person with their profile attributes. You can pick columns, filter the list or export it to CSV. Use it to check that the people who click are the ones you meant to reach.

Below the cards, Funnel timeline shows the stages by day or week, and Revenue attribution shows the campaign’s revenue or transactions against the site’s. The reporting time range can be From start, From last edit (or a specific edit) or a date range you pick. Figures can take 1–3 hours to appear after a session ends. For all your email widgets together, open Analytics → Off-site campaigns → 3rd-party emails.

Tips for best results

• Keep your catalog fresh. Keep a feed in sync, because stale prices and sold-out products lose trust instantly.
• Place the block mid-email. Below the hero banner and above the footer usually gets more clicks than the very top or bottom.
• 3–4 products for transactional emails, 4–6 for dedicated recommendation sends. More products means more scrolling, so test to find your number.
• Set a fallback that makes sense. For subscribers with no history, fall back to Best Sellers or Most Popular rather than random products.
• Match the subject line to the picks. If the subject says “Picked just for you”, make sure behavioural data is arriving before you send at scale.
• Mind the alt text. The snippet’s images carry alt="Recommended". Readers whose email client blocks images, as corporate Outlook often does, see only that, so a clearer call to action there can help.

Related

• Recommendations Outside Your Site — Where to Start: every off-site surface, side by side.
• Content Recommendations in 3rd-Party Emails: the same mechanism for articles.
• Personalized Banners in 3rd-Party Emails: one banner per recipient instead of products.
• Recommendation Algorithms
• Product Interaction Tracking