Coasty Computer Use API Pricing: Every Endpoint, Every Cent
Lisa Chen||5 min
⌘+K
You want an agent that sees a UI, clicks the right button, and types into inputs exactly like a human. Coasty gives you a computer use API that does this on real browsers, desktops, and terminals. You pay per step, per token, and per session. No blind API calls. No brittle selectors. Each endpoint has a precise price so you can budget a computer use agent without guessing.
Billing basics
- ●A prepaid USD wallet where 1 credit is $0.01.
- ●Write operations accept an Idempotency-Key header to make retries safe.
- ●Webhooks are HMAC signed with header Coasty-Signature: t=unix,v1=hex.
- ●Scopes gate access to specific resources like machines or workflows.
- ●Rate limits return 429 when you exceed quotas.
- ●Insufficient credits return 402 INSUFFICIENT_CREDITS.
- ●Invalid or missing key returns 401.
- ●Missing scope returns 403 INSUFFICIENT_SCOPE.
Vision endpoints
- ●POST /v1/predict costs $0.05 per call.
- ●Request: base64 screenshot, instruction, cua_version.
- ●Response: actions, status (loop until status is done).
- ●POST /v1/ground costs $0.03 per call.
- ●Maps a screenshot + element description to x,y coordinates.
- ●POST /v1/parse is free.
- ●Turns pyautogui code into structured actions.
Stateful sessions
- ●POST /v1/sessions costs $0.10 to create.
- ●Request: machine_id, task, cua_version, optional instructions.
- ●Response: session id, memory for trajectory.
- ●POST /v1/sessions/{id}/predict costs $0.04 per call.
- ●Uses session memory for context across steps.
bash
curl https://coasty.ai/v1/predict \
-H 'X-API-Key: $COASTY_API_KEY' \
-H 'Content-Type: application/json' \
-d '{
"screenshot": "$(base64 -w 0 screenshot.png)",
"instruction": "Click the submit button and type a message.",
"cua_version": "v3"
}'Task runs
- ●POST /v1/runs incurs $0.05 per agent step.
- ●Request fields: machine_id, task, cua_version (v3 or v4), instructions, system_prompt, max_steps, deadline_seconds, on_awaiting_human, webhook_url.
- ●Response: run id, initial status (queued, running, awaiting_human, succeeded, failed, cancelled, timed_out).
- ●GET /v1/runs lists runs.
- ●GET /v1/runs/{id} gets a run.
- ●POST /v1/runs/{id}/cancel aborts a run.
- ●POST /v1/runs/{id}/resume resumes a paused run.
- ●GET /v1/runs/{id}/events streams Server-Sent Events (reconnect with Last-Event-ID).
One credit = $0.01. All write operations support Idempotency-Key.
Workflows
- ●POST /v1/workflows creates a versioned JSON DSL of runs.
- ●POST /v1/workflows/{id}/runs triggers a workflow run.
- ●POST /v1/workflows/runs starts an ad-hoc inline workflow.
- ●Step types: task, assert, if, loop, parallel, human_approval, retry, succeed, fail.
- ●Conditions are structured objects.
- ●Variables use double braces: inputs.x and 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.
- ●You can start, stop, and snapshot a machine.
- ●The agent drives real desktops, browsers, and terminals, not just API calls.
Where this beats brittle automation
- ●Vision reads the actual UI, adapting to layout changes.
- ●No fragile CSS selectors or XPath that break on minor diffs.
- ●Real browsers and desktops mean you can automate any web app or desktop tool.
- ●Stateful sessions remember context across steps.
- ●Workflows let you orchestrate multi-step flows with guards and conditions.
- ●You pay per step and per session, not by full automation suite.
Now you know every endpoint and the exact cents you spend. Build a computer use agent that sees the screen, clicks like a human, and handles real apps. Get your API key at https://coasty.ai/developers and start building.