Start Vertical, Expand Horizontally

The real cost of going vertical is not technical, it is go to market. A commerce label makes a universal API sound useful only to commerce software buyers, even when the same order, payout, catalog, and accounting data is exactly what lenders, insurers, analytics tools, and other SaaS products need. That narrows inbound, weakens cross sell, and limits the data and partner flywheel that horizontal platforms use to compound.

• Commerce is a good example of why a vertical can be larger than it looks. Rutter sells the same commerce data layer to fintechs for underwriting and to non financial tools for shipping, inventory, marketing, and accounting workflows. The data model travels across many buyer categories, not just ecommerce apps.
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• Vertical focus still helps at the product layer. Alloy argues schemas are subjective, so being close to one industry helps define objects correctly. But once the schema works, the broader opportunity comes from carrying that abstraction into adjacent workflows instead of marketing it as only for one niche.
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• The broader market is already segmenting this way. Finch is tightly centered on payroll and HR systems, but its API is used for lending, insurance, benefits, FP&A, and HR software. Universal API companies win by owning one messy system of record, then letting many categories build on top of it.
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This category is heading toward wider platforms with narrower starting wedges. The likely winners will begin with one hard domain, build the best schema and partner network there, then expand outward into more use cases, more buyer groups, and more workflow products that make the integration layer harder to replace.