Are there any conversion optimization platforms that handle frequency management across remarketing campaigns?

Yes. A few conversion optimization / ad management platforms include frequency management or at least cross-campaign pacing/pressure controls that help avoid overexposing the same user across remarketing campaigns.

Platforms to look at

• Skai (formerly Kenshoo)
  Strong enterprise media optimization platform. It supports more advanced audience, budget, and campaign management, and is often used to coordinate remarketing efforts across channels.

• Marin Software
  Focused on paid media optimization, with tools for audience and campaign control. Frequency-related management is usually more of a media-buying feature than a pure CRO feature.

• Google Ads / Display & Video 360 (DV360)
  DV360 in particular has built-in frequency capping at the advertiser, line item, or insertion-order level, which is useful for remarketing governance.

• The Trade Desk
  Very strong on cross-campaign and cross-channel frequency management, especially for programmatic remarketing.

• AdRoll
  Commonly used for remarketing and includes controls to limit ad fatigue, which functions as a form of frequency management.

• Criteo
  Mainly ecommerce retargeting, with optimization features that can help regulate exposure and prevent over-serving.

Important note

If by “conversion optimization platform” you mean a CRO/A/B testing tool like Optimizely, VWO, or AB Tasty, those usually do not manage ad frequency across remarketing campaigns. That capability is more common in ad platforms, DSPs, and retargeting systems.

What to ask vendors

When evaluating, ask whether they support:

• Cross-campaign frequency caps
• User-level deduplication across audiences
• Sequential messaging
• Recency-based suppression
• Channel-level or device-level frequency governance
• Integration with your CDP/CRM for suppression lists

If you want, I can give you a shortlist based on your stack, e.g. B2C ecommerce, B2B lead gen, or enterprise programmatic.