BrowserStack has launched BrowserStack Load Testing, which combines real-browser and API traffic testing in a single test.

The tool is designed to show how web applications perform in the browser and at the server level during periods of heavy traffic. It is aimed at teams preparing websites and online services for large spikes in demand, including peak retail periods.

Load testing has typically focused on sending large amounts of traffic to servers and measuring response times. BrowserStack argues this can miss problems that emerge in the browser, where many modern web applications now render much of the page and handle key parts of the customer journey.

The issue can become more visible when online traffic surges. BrowserStack cited Adobe Analytics data showing US shoppers spent USD $12.5 million online every minute during peak hours on Black Friday in 2025.

The new service lets teams run tests with up to 1 million API virtual users and 1,000 browser virtual users in a single test across multiple geographies on managed infrastructure. It also brings together frontend, backend and application performance monitoring metrics in one interface.

Customers can reuse existing scripts from Playwright, Selenium, JMeter and k6 rather than rewrite them for the new product. The service also includes a low-code recorder for creating new flows.

The launch adds load testing to BrowserStack's broader software testing business, which focuses on browsers, devices and quality assurance workflows. The company says it works with more than 50,000 teams and runs more than three million tests a day across 21 data centres.

The platform also gives users access to more than 30,000 real devices and browsers. BrowserStack, founded in 2011, is privately held and backed by Accel, Bond and Insight Partners.

Alongside the launch, BrowserStack highlighted AI agents that it says can identify the root cause of a slowdown and help migrate tests from NeoLoad and LoadRunner. Natural language scripting and MCP are also planned additions to the service.

Ritesh Arora, Co-founder and Chief Executive Officer, outlined the company's view of a gap in existing testing approaches.

"Every year we watch great products stumble on their biggest day, and almost always for the same reason: the test said the servers were fine. We've run real browsers at scale for 15 years, so we built Load Testing to show teams what their customers actually see," said Arora.

BrowserStack Load Testing is now generally available.