Coasty AI – API for Computer-Use Agents

TL;DR

TL;DR: Coasty (YC S26) provides a $0.05 per call API for running AI agents that control a real browser or desktop, with 1,000+ native integrations and a $99 flat-rate unlimited plan.

Source and Accuracy Notes

⚠️ This section is MANDATORY. All links must be verified from actual source, not guessed.

• Project page: coasty.ai ← verified via direct visit
• Docs: coasty.ai/docs ← verified via direct visit
• HN launch thread: news.ycombinator.com/item?id=48922706 ← 44 points, YC S26
• Pricing: verified from schema JSON on coasty.ai/pricing

What Is Coasty?

Coasty is a Y Combinator S26 startup building computer-use agents — AI agents that operate a real browser or desktop the way a human would. Instead of relying on APIs, Coasty agents can click, type, and navigate inside any web or desktop application that has a GUI.

The product has two sides:

1. API — $0.05 per /v1/predict call, with OpenAPI 3.1 spec and free sandbox keys. Targets developers building agents that need to work inside legacy software without APIs.
2. Consumer app — natural-language interface for end users to automate workflows across desktop software.

From the HN launch thread:

“Developers send Coasty a natural-language task either through our consumer app or through our API, select a machine or browser environment, and any relevant credentials or files. The agent then operates the target software like a human would.”

Integrations

Coasty ships with 1,000+ native app integrations out of the box:

• Email: Gmail, Outlook
• Communication: Slack, Teams
• CRM: Salesforce, HubSpot
• Project management: Linear, Asana, Jira
• Development: GitHub, GitLab, Stripe
• And 990+ more

Pricing

| Plan | Price | Credits/mo | |------|-------|------------| | Starter | $19/mo | 200 | | Plus | $50/mo | 600 | | Unlimited | $99/mo | Unlimited | | Boost (one-time) | $19 | 150 credits | | Power Boost (one-time) | $49 | 500 credits |

The Unlimited plan at $99 flat is the notable differentiator — no per-call billing, no credit caps, just 2 machines, 10 schedules, and 5 concurrent agents.

API Reference

Base URL: https://api.coasty.ai

Predict endpoint

POST /v1/predict
Authorization: Bearer <your-api-key>
Content-Type: application/json

{
  "task": "Send a Slack message to #engineering saying deployment is done",
  "environment": "browser",
  "integrations": ["slack"]
}

Environments

• browser — headless browser with full DOM access
• desktop — remote Windows/macOS machine with GUI automation

Setup

1. Get an API key

Sign up at coasty.ai and grab your API key from the dashboard. Free sandbox keys are available.

2. Install the SDK (optional)

npm install @coastyai/sdk

3. Make your first prediction

curl -X POST https://api.coasty.ai/v1/predict \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "task": "Go to github.com and search for Coasty AI",
    "environment": "browser"
  }'

Security Notes

• API keys are scoped per workspace; rotate from the dashboard
• Credentials for integrated apps (OAuth tokens, API keys) are stored encrypted at rest
• Browser and desktop environments run in isolated sandboxes
• SOC 2 compliance is listed on the pricing page as coming soon

FAQ

Q: How is this different from Playwright or Selenium? A: Playwright and Selenium are programmatic browser control libraries — you write the steps manually. Coasty takes a natural-language task and figures out the steps itself, using an AI agent that operates the browser like a human.

Q: What happens if the agent gets stuck? A: The API supports timeout and max-step parameters. The Unlimited plan includes 5 concurrent agents so you can run retries in parallel.

Q: Is there a self-hosted option? A: Not currently. Coasty runs the agent infrastructure on their side. Desktop agents require the Coasty desktop app to be installed on the target machine.

Q: What is OSWorld and why does it matter? A: OSWorld is a benchmark for computer-use agents. Coasty claims 85.60% on OSWorld, which is the score cited on their product page. Higher is better on this benchmark.

Conclusion

Coasty fills the gap for developers who need AI agents to work inside software that has no API — legacy desktop apps, internal tools, and web apps without developer access. The $0.05 per predict pricing is low enough for experimentation, and the $99 unlimited plan makes production workloads predictable.

If you are building agents that need to operate real applications end-to-end, Coasty is worth evaluating. Free sandbox keys are available at coasty.ai.