API gateway scaleup Kong has made its second acquisition, snapping up open-source usage monitoring firm OpenMeter for an undisclosed sum – and promising it has a continued open-source future.

Kong serves a central, cloud-native layer for orchestrating microservices or conventional API traffic. It has an Apache 2.0-licensed community offering and the customary proprietary enterprise SaaS edition with more features.

Its major UK customers include BT. It competes with the likes of older API gateway firms like Apigee and Mulesoft, as well as more cloud-native peers like Solo – and homegrown OSS alternatives built on the likes of Envoy. 

See also: The Big Interview: Kong CTO Marco Palladino

OpenMeter was founded in 2023 by Peter Marton, who previously worked on Stripe's usage and cost platform and Netflix's serverless infrastructure, and Andras Toth, who was earlier at Kubernetes platform company Banzai Cloud (acquired by Cisco) where he worked on its service mesh product. 

Among the things it can do is help organisations track how much each customer uses a given API and create Stripe invoices accordingly. Along with an Apache 2.0 licensed community version it also has (quelle surprise) a managed, SaaS called OpenMeter Cloud that is SOC2 Type 2 compliant.

Kong said: “In the AI era, billing becomes a metering problem. Agents will exchange labor via APIs. Large Language Models (LLM) – if not chats – are already sold via APIs. This requires a new kind of platform that [requires a] unified approach to enforcement, security, and monetization. 

“As AI adoption accelerates, digital connections are no longer deterministic or limited to the pace of human activity… AI agents can trigger thousands of API and data calls per second, increasing both the scale and variability of usage. To capture that value without undercharging or overcharging, organizations need scalable metering and billing built for precision and AI speed.”

Kong’s growth has come as many organisations move API management away from application developers into core platform engineering teams and look for a centralised gateway to manage proxying, routing, load balancing, health checking, authentication, etc. (Modular, microservice-based systems can comprise thousands of individual services communicating via APIs…)

Announcing the acquisition, Kong’s team said that “OpenMeter’s core product will be integrated into Kong Konnect, giving organizations a unified way to measure, bill, and manage usage across all digital assets, including APIs, LLMs, and event streams consumed by AI agents…”

It promised that current and new OpenMeter Cloud platform will carry on getting unbroken service. Integration of OpenMeter into Kong Konnect is expected to be completed early 2026, with customer migration slated for mid-2026.It also promised that OpenMeter will remain an open-source project under Kong, with ongoing development efforts upstream. 

Kong's only previous other acquisition was API testing platform Insomnia in 2019.

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