Is there a limit on how many products I can exclude?

Hype does not set a limit, but Shopify does, and it is not a round number you can plan against. Exclude by collection rather than product by product and you will never meet it.

Where the real limit comes from

Your campaign's rules — the products and collections you included, the ones you excluded, your markets, your tiers — are stored in a Shopify metafield that the discount function reads every time a cart is evaluated. Shopify's Functions limits apply to that:

• Metafield values over 10,000 bytes are not returned to the function at all. A long list of product IDs is what usually pushes a campaign over.
• A list argument can carry at most 100 elements, which caps a campaign at 100 collections between its include and exclude lists.
• Each evaluation has an 11 million instruction budget and a 128 kB input limit. Many product-level rules over products that belong to many collections burn through it.

The failure mode is what makes this expensive: the function stops discounting silently. There is no error in your admin and no message at checkout. If live pricing is on, your storefront still shows discounted prices while orders come through at full price.

The "100 specific customers, products, and variants" limit you may have read about, which produces the error "Item entitlements exceeded max number", is a limit on native Shopify discounts. Hype campaigns are Function discounts and do not use those entitlements — which is why you get no error message when you go too far.

What to do instead

1. Exclude collections, not products. One collection ID replaces a hundred product IDs. Create a "Not on sale" collection, add everything you want excluded to it, and exclude that single collection with Exclude Products / Collections.
2. Invert the rule where you can. If the exclusion list is longer than the list of products you actually want discounted, untick All products and collections and name the products or collections that should be discounted instead.
3. Keep active campaigns to what you need. Every active campaign is evaluated on every cart. Consolidating five overlapping campaigns into one Multi products discount with several discount sets does the same work at less cost.
4. Prefer smart collections. Hype refreshes the products in your collections every 4 hours, and immediately when Shopify tells it a collection changed, so a rule-based collection stays current without you editing the campaign.

How to tell if you have hit it

The symptom is a campaign that behaves correctly on small test carts and does nothing on real ones, or one that stopped working after you added products to it. Rebuild the rules around collections and test again. If it persists, send support the campaign name and a cart that should have been discounted.

Related

• Shopify discount limits cheat sheet
• Multi products discount
• Why a discount didn't apply