Can a customer contract take ownership of my IP?

Yes, if you sign it. Enterprise customers' standard terms frequently contain a clause assigning to the customer all "work product", "deliverables" or "developments" created under the agreement, sometimes including improvements to the supplier's own platform made during the engagement. Read literally, these clauses can transfer to the customer ownership of features you built for everyone, or of a patentable improvement you made while solving their problem, and a signed contract will be enforced as written. Procurement and legal teams include them by default; most will negotiate them, because they were drafted for bespoke consulting, not for buying a product.

The standard fix is a three-part IP clause. The supplier retains all pre-existing IP, its platform and any improvements to it, and grants the customer a licence to use them as part of the service. The customer owns deliverables that are specific to them, such as their data, configurations and custom integrations that have no use elsewhere. And a feedback clause gives the supplier a perpetual, royalty-free licence to use any suggestions the customer makes, without obligation, so that improvements suggested during the relationship stay yours to build and patent. Where the customer insists on owning a genuine joint development, treat it as a joint development agreement with defined background and foreground IP rather than a sales contract. Having filed applications on your core technology before the negotiation makes all of this easier, because "supplier background IP" can then be defined by reference to specific patent applications instead of by argument. This is general information, not advice on a specific contract; have a lawyer review the clause before you sign.