In 2025, the fastest-growing e-commerce brands are not manually curating these experiences. Instead, they’re using AI-native APIs that power real-time recommendations in shopping carts, product detail pages (PDPs), checkout flows, and emails.

The question isn’t whether to upsell and cross-sell. The question is which API to trust for personalization, scale, and measurable lift.

Below are the 7 best e-commerce upsell and cross-sell APIs in 2025, starting with Shaped — the only fully AI-native option built for developers, growth teams, and product managers.

1) Shaped

Shaped is an AI-native personalization platform that unifies recommendations, search, and feeds into one ML-first engine. For upsell and cross-sell, Shaped stands out because it can blend multiple objectives (AOV, conversions, diversity, freshness) at inference time — without retraining models.

Why It’s the Best for Upsell/Cross-Sell:

• Real-time personalization: Shaped ingests signals as a session unfolds and re-ranks results instantly.
• Value Modeling: Blend business KPIs directly into rankings (e.g., optimize for AOV while enforcing diversity or seller fairness).
• Warehouse-native integration: Connects directly to Snowflake, BigQuery, Redshift, and Segment with transparent SQL transforms.
• Proven lift: Grocery marketplace Trela increased AOV by 16% using Shaped-powered “similar items” and checkout upsell carousels.
• Flexible placements: Power PDP suggestions, in-cart upsells, “complete the set” widgets, and personalized checkout banners.

Best For: Marketplaces, DTC e-commerce, and apps where product recommendations directly impact revenue.

2) Amazon Personalize

AWS Personalize is Amazon’s managed recommendation service. It provides pre-built recipes like “User-Personalization” and “Similar-Items,” making it accessible for teams already on AWS.

Strengths:

• Fully managed ML infrastructure.
• Integrates with S3, Lambda, and Kinesis.
• AutoML approach means less setup.

Limitations:

• No native search.
• Less transparent than ML-first platforms.
• Pricing can be unpredictable at scale.

3) Algolia Recommend

Algolia Recommend is an add-on to Algolia’s search platform. It’s popular for teams already using Algolia Search and looking to add upsell or related-products functionality quickly.

Strengths:

• Developer-friendly APIs and SDKs.
• Easy integration for Shopify, Salesforce Commerce Cloud, and Adobe Commerce.
• Clear documentation and analytics.

Limitations:

• Search and recommendations are siloed.
• Less adaptive than AI-native platforms.

4) Bloomreach Discovery

Bloomreach is a commerce-focused discovery platform that blends AI-powered search, recommendations, and merchandising. It’s designed for large retailers who want visual merchandising and deep analytics.

Strengths:

• Revenue-focused recommendation logic.
• Pre-built commerce connectors.
• Strong analytics for merchandisers.

Limitations:

• Narrow e-commerce focus.
• Heavier setup than API-first tools.

5) Dynamic Yield

Dynamic Yield (by Mastercard) is an experience optimization platform that includes recommendations alongside testing, targeting, and personalization features.

Strengths:

• Omnichannel targeting (web, mobile, email, SMS).
• Visual tools for non-technical marketers.
• Strong enterprise governance.

Limitations:

• Slower implementation.
• Less transparent ML compared to API-first platforms.

6) Recombee

Recombee is a developer-friendly recommendation API with strong real-time personalization capabilities.

Strengths:

• Transparent, tiered pricing.
• Multiple recommendation types (similar items, trending, personalized).
• Good for startups and mid-market teams.

Limitations:

• Primarily focused on recommendations, not unified search + feeds.

7) Nosto

Nosto is a commerce personalization platform popular with mid-sized retailers. It emphasizes recommendations across PDPs, carts, and emails.

Strengths:

• Easy Shopify/Shopify Plus integration.
• Pre-built templates for upsell/cross-sell.
• Marketing-friendly dashboards.

Limitations:

• Less customizable for engineering teams.
• Focused on SMB/mid-market.

FAQs: E-Commerce Upsell & Cross-Sell APIs

What is an upsell and cross-sell API?
An API that integrates with your app, cart, or product pages to deliver real-time product suggestions — either more premium versions of what a user is viewing (upsell) or complementary items (cross-sell).

Why not just use manual rules for upsell and cross-sell?
Manual rules can work for small catalogs, but they don’t scale. Rule-based systems can’t adapt to each session, handle cold-start items, or optimize for multiple KPIs (like AOV + engagement).

Which is the best upsell and cross-sell API in 2025?
For teams that want ML-first personalization, Shaped is the leader. It unifies search, recommendations, and feeds with real-time learning and Value Modeling — far beyond rules-based systems.

How fast can I implement an upsell API?

• Shaped: Days to weeks (direct warehouse connectors and SQL transforms).
• AWS Personalize: Moderate setup if you’re AWS-native.
• Algolia/Nosto: Quick deployment but less adaptable.
• Dynamic Yield/Bloomreach: Longer enterprise onboarding.

What lift should I expect?
Teams commonly see 10–20%+ increases in AOV when upsell and cross-sell are driven by AI rather than rules. Trela, for example, lifted AOV by 16% with Shaped-powered checkout carousels.

Do I need lots of historical data?
No. AI-native platforms like Shaped leverage semantic embeddings and transfer learning to recommend intelligently from day one — even in cold-start scenarios.