Coasty Computer Use API Pricing: Every Endpoint, Every Cent

Core pricing model

• ●1 credit = $0.01 USD. Every write operation charges credits from your prepaid wallet.
• ●Agent steps are billed at $0.05 per step. This applies to POST /v1/runs and POST /v1/workflows task steps.
• ●Vision actions cost $0.05 for a single predict call that returns actions from a screenshot.
• ●Stateful sessions cost $0.10 to create and $0.04 per predict call that uses trajectory memory.
• ●Grounding costs $0.03 per POST /v1/ground call that maps a screenshot and description to x,y coordinates.
• ●POST /v1/parse is free and converts pyautogui code into structured actions.
• ●Rate limits and insufficient credits return 429 and 402 errors respectively.
• ●Use X-API-Key or Authorization: Bearer headers for authentication.
• ●Webhook payloads are HMAC signed with header Coasty-Signature: t=unix,v1=hex.

Task Runs: your main agent driver

• ●POST /v1/runs starts a server-driven agent on a provisioned machine.
• ●Required fields: machine_id, task, cua_version (v3 or v4).
• ●cua_version v4 is autonomous with a pass/fail verifier.
• ●Optional fields: instructions (appended to the base prompt), system_prompt, max_steps, deadline_seconds, on_awaiting_human, webhook_url.
• ●Billed $0.05 per agent step.
• ●States: queued, running, awaiting_human, succeeded, failed, cancelled, timed_out.
• ●GET /v1/runs lists runs for a machine.
• ●GET /v1/runs/{id} returns a single run's details.
• ●POST /v1/runs/{id}/cancel stops a run.
• ●POST /v1/runs/{id}/resume resumes after cancellation.
• ●GET /v1/runs/{id}/events streams Server-Sent Events with Last-Event-ID support.

Workflows: versioned JSON DSL

• ●POST /v1/workflows creates a versioned workflow definition.
• ●POST /v1/workflows/{id}/runs starts a run of a workflow.
• ●POST /v1/workflows/runs executes an ad-hoc inline workflow.
• ●Step types: task, assert, if, loop, parallel, human_approval, retry, succeed, fail.
• ●Variables use double-brace syntax: {{inputs.x}} and stepId.field.
• ●Hard guards: budget_cents, max_iterations, deadline_seconds.
• ●Task steps are billed $0.05 each.

Vision and grounding

• ●POST /v1/predict takes a base64 screenshot, instruction, and cua_version.
• ●Returns actions and a status. Loop capture, predict, act until status is done.
• ●Cost: $0.05 per predict call.
• ●POST /v1/sessions creates a stateful session with trajectory memory.
• ●POST /v1/sessions/{id}/predict uses the session to retain context.
• ●Cost: $0.10 for session creation, $0.04 per predict call.
• ●POST /v1/ground maps a screenshot plus element description to x,y coordinates.
• ●Cost: $0.03 per grounding call.

Machines and billing

• ●POST /v1/machines provisions a cloud VM you can start, stop, and snapshot.
• ●Agents run on real desktops, browsers, and terminals via machine_id.
• ●Billing uses a prepaid USD wallet.
• ●Use Idempotency-Key header for safe retry on writes.
• ●Scopes gate API access per key.
• ●An MCP server lets you drive Coasty from Cursor, Claude Desktop, and compatible clients.

Where this beats brittle automation

Coasty agents see the screen and act like a human, not just match text or IDs. This means they adapt to layout changes, dynamic classes, and unknown elements. You do not need to maintain fragile selectors or brittle APIs. Your agents can click, scroll, fill forms, and navigate complex UIs on real browsers and desktops. This reduces maintenance and improves reliability for complex workflows.