Clay's killer feature is composability. You drop in a list of domains or names and orchestrate 50+ data providers (plus AI agents) to fill in everything else — title, tech stack, hiring signals, recent funding, custom inferences from public web. It's a builder's tool, more flexible than any single data vendor and roughly an order of magnitude cheaper at typical seat counts.
ZoomInfo's edge is depth. Buyer-committee mapping ("who reports to whom inside this 10K-person target account"), intent data, technographics, deeper coverage of private companies and specific industries. For enterprise sales orgs whose territory plans depend on knowing the org chart of every Fortune 500 target, it's still the best in class. Cost is multiples of Clay and the contract is annual.
Most modern teams we've worked with use Clay first and only add ZoomInfo when a specific data depth need can't be solved with composable enrichment. Worth running the cheaper experiment before committing to the bigger contract.