What is a Browser Agent?

Most software automation relies on APIs, but a huge share of the useful web has no API at all, or one that doesn't expose the specific action needed. A browser agent closes that gap by interacting with the same rendered interface a human would: it takes a screenshot or reads the accessibility tree, decides what to click or type based on the current page state, and adapts when the page layout or content differs from what it expected. Browser agents are inherently more fragile than API-based automation because they depend on a visual or DOM structure that a website owner can change without notice, and they run slower since each step requires a full page render and interpretation cycle. They're used specifically when no API path exists — for logging into legacy portals, filling out government forms, or extracting data from sites that actively resist scraping.