[DigitalToday reporter Chi-gyu Hwang] Stripe, a leading B2B payments company, acquired startup Metronome, which specialises in real-time usage metering and billing systems, for about $1 billion in January 2026.

With money, staff and similar technology already in hand, Stripe chose to spend heavily on an acquisition instead of building it internally.

According to Lago CEO Anh-Tho Chuong (안 토 추엉), there are reasonable grounds for that. From a software architecture perspective, an acquisition can be a cheaper option than building in-house.

In a recent post shared on X, Chuong said the cost of changing early decisions can at times be higher than acquiring a company that made different choices, citing Stripe's Metronome deal as an example.

Stripe launched Stripe Billing in 2018 to support usage-based billing. Stripe Billing was designed for the SaaS subscription model that was mainstream at the time. Back then, Stripe Billing did not pose major problems.

But when usage-based pricing becomes not an add-on but the business model itself, the situation changes, Chuong said.

Chuong said, "Stripe was not built to process billions of raw data points in real time. It also cannot issue an invoice when a customer crosses a $10,000 threshold in the middle of the month. The whole system assumes monthly or annual cycles. OpenAI hit this wall. It had to measure billions of inference events under a complex pricing scheme. It needed to charge immediately when customers used up credits, but that was impossible with the Stripe Billing structure," he said.

It was not only OpenAI.

He said, "Every company that adds AI features takes on the same billing complexity. Design tools that add AI generation features have to track tokens. Developer platforms that add code completion have to charge per suggestion. As AI features shift from optional to core differentiation, costs become directly proportional to usage. Suddenly, every software company needs real-time metering and instant charging. With the structure of Stripe Billing, all of them need to build a separate metering system in front of Stripe," he said.

With a company the size of Stripe, it may seem like something it can build itself, but it may not be as easy as it appears when looking at the whole system.

While maintaining the Stripe Billing system, Stripe acquired Metronome and expanded into areas that are hard for Stripe Billing to cover.

Chuong said, "The lesson from Stripe's acquisition of Metronome is clear. Design decisions made for one generation of products become structural constraints as the market evolves. Stripe Billing's subscription-centred structure was the right choice in 2018. It just did not fit the AI-era usage models that emerged five years later. And Stripe made the rational choice of an acquisition instead of rebuilding the software," he said.