Coasty Computer Use API Pricing: Every Endpoint, Every Cent

How it works

The Coasty computer use API models a human at a screen. The client sends a screenshot and instruction, the model returns an action, and the loop continues until the status is done. You can run this as a simple stateless loop or as a stateful session with trajectory memory. Every step is billed at the same rate, giving you predictable compute costs.

Vision endpoints

• ●/v1/predict - $0.05 per call. Sends a base64 screenshot + instruction + cua_version and returns actions + status. Use this for a simple loop: capture, predict, act until status is done.
• ●/v1/sessions - $0.10 to create a stateful session. Then use /v1/sessions/{id}/predict for each step at $0.04. This gives you trajectory memory across steps.
• ●/v1/ground - $0.03 per call. Takes a screenshot + element description and returns x,y coordinates for precise clicks or inputs.
• ●/v1/parse - Free. Transforms pyautogui code into structured actions. Great for converting existing scripts into computer use actions.

Task Runs

• ●POST /v1/runs - Creates a task run. Parameters include machine_id, task, cua_version (v3 default, v4 enables autonomous pass/fail verification), instructions (appended to the base prompt), system_prompt, max_steps, deadline_seconds, on_awaiting_human (pause/fail/cancel), and webhook_url.
• ●GET /v1/runs - Lists runs for a machine.
• ●GET /v1/runs/{id} - Retrieves a specific run status and details.
• ●POST /v1/runs/{id}/cancel - Stops an in-progress run.
• ●POST /v1/runs/{id}/resume - Resumes a paused run.
• ●GET /v1/runs/{id}/events - Streams Server-Sent Events for real-time progress, reconnect with Last-Event-ID.
• ●States: queued, running, awaiting_human, succeeded, failed, cancelled, timed_out.
• ●Billed $0.05 per agent step.

Workflows

• ●POST /v1/workflows - Uploads a versioned JSON DSL of runs with steps like task, assert, if, loop, parallel, human_approval, retry, succeed, fail.
• ●Conditions are structured objects. Variables use double-brace syntax like inputs.x or stepId.field.
• ●Hard guards: budget_cents, max_iterations, deadline_seconds.
• ●Task steps are billed $0.05 each.

Machines

• ●POST /v1/machines provisions a cloud VM that the agent can start, stop, and snapshot. The agent drives real desktops, browsers, and terminals, not just API calls.

Billing model

• ●A prepaid USD wallet where 1 credit equals $0.01.
• ●Webhooks are HMAC signed with header Coasty-Signature: t=unix,v1=hex.
• ●Idempotency-Key header makes writes safe to retry.
• ●Scopes gate keys.
• ●There is an MCP server so you can drive Coasty from Cursor, Claude Desktop, or other MCP clients.

Where this beats brittle automation

Traditional automation relies on selectors, IDs, and XPath that break when UIs change. The Coasty computer use API models a human at the screen: it sees the current screenshot and returns actions that work even when selectors disappear. This makes your agents resilient to UI redesigns, dynamic content, and web application updates.