Writing automation is hard. You map IDs, write selectors, and debug when UI changes. The Coasty computer use API changes that. It lets you describe a task in natural language and a model drives a real desktop, browser, or terminal like a human. You start with a prototype, then move to production using stateful sessions, workflows, and cloud machines.
How the API works
You send a task description and a cua_version. The server launches a machine, runs an agent, and returns events. The computer use API handles screen capture, action prediction, and execution. You pay per agent step, not per API call. Use the /v1/runs endpoint to start a task run. The server streams events via Server-Sent Events. When the run reaches a terminal state, you get the final outcome.
curl -X POST https://coasty.ai/v1/runs \
-H "X-API-Key: $COASTY_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"machine_id": "default",
"task": "open google.com and search for docker",
"cua_version": "v3",
"max_steps": 20,
"deadline_seconds": 300,
"on_awaiting_human": "pause"
}'Core fields and pricing
- machine_id: ID of the target machine.
- task: Natural language description of the work.
- cua_version: v3 for guided runs, v4 for autonomous with pass/fail verifier.
- max_steps: Maximum agent steps before timeout.
- deadline_seconds: Hard deadline for the run.
- on_awaiting_human: pause, fail, or cancel when UI needs input.
- Webhook URL: optional endpoint to receive status updates.
- Billing: $0.05 per agent step. No charge for API calls themselves.
Pay $0.05 per agent step, not per API call. Use stateful sessions and workflows to scale.
Where this beats brittle automation
Traditional automation relies on selectors, IDs, or XPath. If an element moves, your script breaks. The computer use API looks at the screen, understands the layout, and clicks or types based on visual context. This makes automation robust to UI changes. It also works on terminals and desktop apps where standard APIs are absent.
Start prototyping with /v1/runs. Add stateful sessions, workflows, and cloud machines for production. Build agents that do real work on real systems. Get your API key at https://coasty.ai/developers .
Want to see this in action?
View Case Studies