Hey HN, we’re Nitish and Prateek, founders of Coasty (YC S26) – an API that lets computer‑use agents complete workflows in legacy desktop software and web applications without exposing a usable API. Developers send a natural‑language task via the consumer app or API, choose an environment, supply credentials or files, and the agent operates the interface through screenshots, mouse, and keyboard input, verifying the result and returning a structured run record with screenshots, actions, outputs, and errors.

A raw demo shows an agent finishing a workflow in a legacy app. Many critical tools – payer portals, accounting desktops, operations – still lack robust APIs or take months to integrate. Traditional RPA records clicks and replays, but it breaks when a button moves, a pop‑up appears, or the app changes state. Coasty observes the screen, decides the next action, executes it, and verifies the new state, requiring no DOM access or selectors, so the same API works across browsers, remote desktops, and older Windows apps.

Runs run in isolated VMs. The API exposes provisioning, file uploads, task submission, event streaming, human approvals, and audit trails. Developers can set invariants (e.g., patient name must match the source) and pause for approval. Coasty currently biases toward slower, verified execution to avoid mistakes in sensitive workflows, charging by runtime and workflow volume with separate pricing for dedicated environments.

We’re starting with healthcare operations and invite feedback from anyone who’s built or used browser agents, RPA, or desktop automation. Tell us which parts of the API you’d like more control over, which failure modes have been hardest, and any weird automation glitches you’ve encountered. We’ll be answering questions all day.