When you build a computer use agent, cost is not an afterthought. Every API call, every prediction, every step of a task run adds up. You need to know exactly what you pay for and how much each operation costs. The Coasty computer use API is transparent. Below is a complete breakdown of every endpoint, its purpose, and its price, so you can budget automatically and scale with confidence.
Vision endpoints: predict and ground
The vision endpoints let you send a base64 screenshot to the model with instructions and get actions back. You can also map visual descriptions to x,y coordinates. These are billed per call.
curl https://coasty.ai/v1/predict \
-H 'X-API-Key: $COASTY_API_KEY' \
-H 'Content-Type: application/json' \
-d '{
"screenshot": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==",
"instruction": "Click the button labeled Submit",
"cua_version": "v3"
}'POST /v1/predict costs $0.05 per call.
Session-based vision: predict with stateful trajectory
Use sessions to keep a trajectory in memory. You create a session, then send predictions with a lower per-call price. This is useful when you need to remember past actions across frames.
import os, base64, requests, json
def predict_with_session():
api_key = os.environ.get('COASTY_API_KEY')
headers = {'X-API-Key': api_key, 'Content-Type': 'application/json'}
# 1. Create a session
resp = requests.post('https://coasty.ai/v1/sessions', headers=headers, json={})
session = resp.json()
session_id = session['id']
# 2. Predict within the session
payload = {
'screenshot': 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==',
'instruction': 'Click the button labeled Submit',
'cua_version': 'v3'
}
resp = requests.post(f'https://coasty.ai/v1/sessions/{session_id}/predict', headers=headers, json=payload)
return resp.json()
result = predict_with_session()
print(json.dumps(result, indent=2))POST /v1/sessions costs $0.10 and POST /v1/sessions/{id}/predict costs $0.04 per call.
Grounding: map screenshots to element coordinates
POST /v1/ground maps a screenshot and an element description to x,y coordinates. This is billed $0.03 per call and helps you find interactive targets reliably.
curl https://coasty.ai/v1/ground \
-H 'X-API-Key: $COASTY_API_KEY' \
-H 'Content-Type: application/json' \
-d '{
"screenshot": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg==",
"description": "The submit button"
}'POST /v1/ground costs $0.03 per call.
Task Runs: the server drives an agent to completion
Task Runs let you offload an entire task to an agent. You POST /v1/runs with machine_id, task, cua_version, instructions, system_prompt, max_steps, deadline_seconds, and on_awaiting_human. You are billed $0.05 per agent step. You can poll or stream events.
curl https://coasty.ai/v1/runs \
-H 'X-API-Key: $COASTY_API_KEY' \
-H 'Content-Type: application/json' \
-d '{
"machine_id": "vm-123",
"task": "Open Chrome and navigate to example.com",
"cua_version": "v4",
"max_steps": 30,
"deadline_seconds": 300,
"on_awaiting_human": "pause",
"webhook_url": "https://your-domain.com/webhook"
}'Task Run states and HTTP endpoints
Task Runs have states: queued, running, awaiting_human, succeeded, failed, cancelled, timed_out. You can list, get, cancel, and resume runs. These operations are free.
# List runs
curl https://coasty.ai/v1/runs -H 'X-API-Key: $COASTY_API_KEY'
# Get a specific run
curl https://coasty.ai/v1/runs/abc123 -H 'X-API-Key: $COASTY_API_KEY'
# Cancel a run
curl -X POST https://coasty.ai/v1/runs/abc123/cancel \
-H 'X-API-Key: $COASTY_API_KEY'
# Resume a run
curl -X POST https://coasty.ai/v1/runs/abc123/resume \
-H 'X-API-Key: $COASTY_API_KEY'Workflows: versioned JSON DSL of runs
Workflows let you encode a sequence of steps as a versioned JSON DSL. You can POST /v1/workflows, /v1/workflows/{id}/runs, or inline /v1/workflows/runs. Steps include task, assert, if, loop, parallel, human_approval, retry, succeed, fail, with conditions, variables, budget_cents, max_iterations, and deadline_seconds. Task steps are billed $0.05 each.
import os, json, requests
def create_workflow():
api_key = os.environ.get('COASTY_API_KEY')
headers = {'X-API-Key': api_key, 'Content-Type': 'application/json'}
workflow = {
"name": "example-workflow",
"version": "1.0",
"steps": [
{
"type": "task",
"task": "Open Chrome and navigate to example.com"
},
{
"type": "assert",
"condition": {
"field": "title",
"operator": "contains",
"value": "Example Domain"
}
},
{
"type": "succeed"
}
],
"budget_cents": 100,
"max_iterations": 10,
"deadline_seconds": 300
}
resp = requests.post('https://coasty.ai/v1/workflows', headers=headers, json=workflow)
return resp.json()
workflow = create_workflow()
print(json.dumps(workflow, indent=2))Machines: provision cloud VMs for real desktops
POST /v1/machines provisions a cloud VM you can start, stop, and snapshot. The agent can drive real desktops, browsers, and terminals, not just API calls. This operation is free.
curl https://coasty.ai/v1/machines \
-H 'X-API-Key: $COASTY_API_KEY' \
-H 'Content-Type: application/json' \
-d '{
"name": "my-agent-vm",
"os": "linux",
"size": "small"
}'Billing and configuration
Billing uses a prepaid USD wallet where 1 credit equals $0.01. Webhooks are HMAC signed with header Coasty-Signature: t=unix,v1=hex. Keys are scoped and read from COASTY_API_KEY environment variable. Idempotency-Key provides replay safety only for the 18 documented reserve-and-replay operations when present on the original request.
Where computer use beats brittle automation
Traditional automation relies on fragile selectors and API mocks. A computer use agent sees the screen, understands context, and acts like a human. It handles layout changes, dynamic content, and UI variations without hard-coded selectors. This makes it far more resilient and easier to maintain at scale.
With transparent pricing for every endpoint you can model costs into your software from day one. Build reliable computer use agents, automate complex workflows, and scale without surprises. Get your key at https://coasty.ai/developers and start coding with confidence.
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