Open APIs Are Over | Tomasz Tunguz
Open APIs Are Over
January 10, 2026
saas strategy ai startups
Salesforce, Datadog & Epic are building walls. After two decades of flourishing through open APIs & data portability, the software industry’s largest incumbents are locking down.
Salesforce restricted Slack’s API1 in May 2025, limiting third-party apps to one API call per minute & fifteen messages per request. Datadog deactivated accounts2 for Deductive AI, a competing observability startup. Epic faces a Texas lawsuit3 accusing it of turning patient records into a “gatekeeping tool.”
The pace of software development, as a result of AI, is accelerating, enabling incumbents to broaden their suite & compete with previous partners. Faster execution means more defense from those with established businesses. This is the new normal.
Platform businesses have minted billions in the past. Vlocity ($1.33B acquisition)4 & Veeva ($36B market cap)5 built multi-billion dollar businesses on the Salesforce platform. nCino reached a $2.9B market cap6 serving financial services on Salesforce. ServiceMax sold to GE Digital for $915M7. Klaviyo built a $8.8B business8 with 78% of its revenue from Shopify customers.
But building on top of a system of record offers less stable ground than it once did. When Salesforce throttles Slack’s API, they’re telegraphing where the value is. When Epic locks down patient records, they’re drawing a map. Incumbents don’t build walls around worthless assets. And they don’t build defenses unless they perceive credible & urgent challengers.
AI’s speed enables both startups & incumbents to own a stack end-to-end. That’s offense in an era of walls. 1. Computerworld : Salesforce changes Slack API terms ↩︎