Vertical Integration by Polymarket and Kalshi

The real risk is not that Polymarket and Kalshi have better APIs, it is that they are turning market data into a customer acquisition channel that feeds trading volume back into their own exchanges. Once a platform can publish live odds through major media partners, run native developer tools, and keep the underlying liquidity in house, an aggregator like Dome risks becoming a convenience layer on top of someone else’s distribution and economics.

• Dome helps by normalizing different market structures into one schema and routing orders to the best venue, because Polymarket is blockchain based and Kalshi runs a regulated closed database. That technical gap is the reason an aggregator exists, but it is also why the exchanges can keep improving their own first party tooling over time.
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• The prize is not just API revenue. Polymarket and Kalshi are racing to become the default liquidity backends for brokers, sportsbooks, exchanges, and media companies. In that market, the venue with the most order flow gets tighter books, better prices, and even more partners, which compounds against third party data vendors.
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• This looks more like Bloomberg Terminal versus an exchange than like Stripe versus fragmented payment rails. If Wall Street Journal, MarketWatch, Barron’s, Investor’s Business Daily, and CNBC are already carrying native prediction data from the venues themselves, the exchanges can bundle distribution, data, and execution before independents get inserted into the workflow.
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The next phase is a fight over who owns the interface between end demand and exchange liquidity. If prediction markets keep spreading into brokerages, sportsbooks, and news products, Dome’s strongest path is to sit above a growing long tail of niche venues while Polymarket, Kalshi, and CME FanDuel try to lock up the highest volume channels directly.