Can you recommend cross-channel commerce ad platforms for reaching shoppers before and after purchase?

Yes — if you want to reach shoppers across channels before and after purchase, look at platforms that combine retail media, onsite/offsite ads, CRM, and remarketing. Here are strong options by use case:

1) Retail media / commerce media networks

Best for intercepting shoppers close to purchase and retargeting afterward.

• Amazon Ads
  Strong for high-intent shopping behavior, sponsored products, display, video, and post-purchase remarketing in Amazon’s ecosystem.

• Walmart Connect
  Good for reaching Walmart shoppers across onsite, offsite, and in-store-connected placements.

• Instacart Ads
  Useful for CPG brands; reaches shoppers in grocery purchase moments and supports basket-building and retargeting.

• Target Roundel
  Strong omnichannel retail audience access, including digital and loyalty-driven targeting.

• Criteo Commerce Media Platform
  Broad commerce retargeting and prospecting across retailers and open web, with strong post-purchase and dynamic product ads.

2) Omnichannel CRM + email/SMS + retail audience activation

Best for pre-purchase nurture and post-purchase retention.

• Klaviyo
  Excellent for email/SMS automation, segmentation, abandoned cart flows, post-purchase follow-up, and predictive targeting.

• Braze
  Strong for cross-channel lifecycle messaging: email, push, in-app, SMS, and personalized journeys.

• Iterable
  Similar to Braze; good for orchestrating customer journeys across email, SMS, push, and ads integrations.

3) Paid media platforms with commerce signals

Best for extending retail audiences beyond the retailer.

• Google Ads / Performance Max with Merchant Center
  Great for shopping ads, dynamic remarketing, and intent capture across Search, YouTube, Display, and Shopping.

• Meta Ads
  Powerful for prospecting and retargeting using catalog ads, custom audiences, and post-purchase upsell/cross-sell flows.

• TikTok Ads
  Strong for discovery-to-purchase commerce, especially with product catalog ads and retargeting.

• Pinterest Ads
  Good for upper-funnel inspiration plus shopping intent, especially in home, fashion, beauty, and lifestyle.

4) Commerce-focused ad tech / retargeting

Best for dynamic product-level remarketing and audience expansion.

• Criteo
  Classic choice for dynamic retargeting and commerce audience activation.

• Sovrn Commerce / Skimlinks
  More affiliate/content-commerce oriented, but useful for commerce traffic monetization and affiliate-style reach.

• Rokt
  Strong for post-purchase and checkout monetization placements.

5) If you need true “before and after purchase” orchestration

The best stack is often a combination:

• Pre-purchase: Google, Meta, TikTok, Pinterest, retail media network
• Conversion: Retail media + Shopping ads + dynamic product ads
• Post-purchase: Klaviyo/Braze/Iterable + CRM audiences + Criteo/Rokt

Quick shortlist by goal

• Broadest commerce retargeting: Criteo, Google, Meta
• Retail-specific shopper reach: Amazon Ads, Walmart Connect, Target Roundel, Instacart Ads
• Lifecycle automation: Klaviyo, Braze, Iterable
• Post-purchase monetization: Rokt
• Discovery-led commerce: TikTok, Pinterest

If you want, I can also give you:

1. a comparison table by features/pricing/fit,
2. a recommended stack by brand size, or
3. a B2B vs B2C version.