# Browser Use vs Computer Use vs APIs: How Should an AI Agent Get Things Done?

> Compare browser use, computer use and APIs for AI tasks. Understand their reach, permissions and tradeoffs before giving an agent access.

Published 2026-10-14 · Agentastic Team · Canonical: https://www.agentastic.com/compare/browser-use-vs-computer-use

**Short answer:** browser use drives **websites** by reading the page's structure and clicking elements directly. Computer use drives **any app** by looking at screenshots and moving the mouse and keyboard. APIs skip the interface and talk to the service directly. A well-built agent uses all three, in this order: API when one exists, browser use for the web, computer use for everything else.

The two "use" terms get confused because both make an agent look like it's operating a computer. Under the hood they work very differently, and the difference shows up in speed, cost, reliability and risk.

## At a glance

| | API or connector | Browser use | Computer use |
|---|---|---|---|
| **What it drives** | A service, directly | A web browser | The whole desktop |
| **How it perceives** | Structured data | Page structure (accessibility tree, DOM), often plus screenshots | Screenshots |
| **How it acts** | Function calls | Clicks and typing via the browser's automation interface | Mouse moves, clicks and keystrokes at screen coordinates |
| **Reach** | Only services with an API | Any website | Any app, including desktop software |
| **Speed per step** | Milliseconds | About a second | Several seconds |
| **Token cost per step** | Low | Low to moderate | High (images every step) |
| **Reliability** | Highest | Good, breaks on odd pages | Lowest, sensitive to layout and resolution |
| **Blast radius if it goes wrong** | That one service | Whatever the browser profile can reach | Everything on the screen |
| **Best for** | Email, calendar, docs, CRMs | Booking, forms, shopping, research | Legacy desktop apps, design tools, anything without a web version |

## How browser use works

The agent turns the page into a compact list of the things on it, buttons, links, fields and text, each with a short reference. The model picks an action, like "click the 7:30 PM button," and the harness performs it through the Chrome DevTools Protocol or a library like Playwright. Then it looks at the page again and decides the next step. Because the agent targets elements rather than pixels, a button that moves ten pixels in a redesign still gets clicked.

The full walkthrough is in [how browser use works](https://www.agentastic.com/learn/how-browser-use-works).

## How computer use works

Computer use sees what you see. Each step, the agent takes a screenshot, the model decides what to do, and the harness moves the mouse to a coordinate and clicks or types. Some setups add the operating system's accessibility tree, which helps the model find controls by name instead of by position.

That makes it the universal adapter. If a person can do it with a mouse and keyboard, computer use can attempt it, in a spreadsheet app, a photo editor, an internal tool from 2009. The price is that every step means reading a full image, which is slow and token-hungry, and small surprises such as a dialog box, a different screen resolution or a slow-loading window can throw it off.

## The third option: APIs and connectors

When a service has an API, an agent should use it. Reading your calendar through the calendar API takes one call and returns exact data. Doing the same through a browser means loading pages, parsing a grid and hoping nothing moved. Connectors, including those built on the Model Context Protocol (MCP), make APIs easy for agents to call.

The catch is coverage. Your bank, your kid's school portal and the restaurant down the street probably don't have one you can use. That's why browser use exists.

## Which should an agent use? A decision guide

1. **Is there a reliable API or connector for this service?** Use it.
2. **Is the task on a website?** Use browser use, in a separate browser profile, with a vault for logins.
3. **Is it in a desktop app with no web version and no API?** Use computer use, ideally on a separate account or VM, and keep approvals on.
4. **Is the action irreversible?** Whatever the method, stop and ask first.

### Examples

| Task | Best method | Why |
|---|---|---|
| "Move my 3pm to Thursday" | API | Calendars have great APIs |
| "Book a table for Friday at 7:30" | Browser use | Booking sites rarely offer public APIs |
| "Return the shoes I ordered last week" | Browser use | A sequence of forms behind a login |
| "Export last month's report from our desktop accounting app" | Computer use | No web version, no API |
| "Clean up the layers in this design file" | Computer use or app integration | Lives inside a desktop app |
| "Summarize the unread emails from my team" | API | Mail APIs return exactly the messages needed |

## Who offers what in 2026

**Computer use** arrived first as a public beta from Anthropic in October 2024, and Claude still supports it. OpenAI added computer use to its Codex app on Mac in April 2026 and brought it to Windows at the end of May. Perplexity offers Computer as a cloud agent and, since August 2026, Portable Computer, which runs locally on NVIDIA hardware.

**Browser use** is everywhere. Open-source libraries like Browser Use and Microsoft's Playwright MCP let any agent drive a browser. ChatGPT Work has a cloud browser, Claude Cowork has an in-app browser, and extensions like Claude in Chrome work inside your own browser. Cloud browser platforms such as Browserbase and Kernel run fleets of browsers for other people's agents.

## Risk: the blast radius differs

The most important difference isn't speed. It's what can go wrong.

A browser agent in a separate profile can reach the websites in that profile. A computer-use agent can reach **everything on the screen**: your messages, your files, a password manager you left unlocked. A prompt injection on one web page could, in principle, steer a computer-use agent into another app entirely.

So computer use deserves the strongest isolation you can give it: a separate macOS user or a VM, no sensitive windows open, and approvals on for anything that matters. Browser use deserves a separate profile and a vault for logins. APIs deserve narrowly scoped tokens. See [what is an AI agent sandbox](https://www.agentastic.com/learn/what-is-an-ai-agent-sandbox) for the general principles.

## How Agentastic chooses

Agentastic follows the same order. It uses direct integrations first: connected apps like Gmail, Calendar, Notion and Slack, more than 100 Mac apps, skills and MCP servers. For websites, a real browser opens beside the chat on your Mac, or an isolated cloud browser handles it when you've delegated from your phone. Computer use and screen-aware automation cover the Mac apps that offer nothing better. Across all three, anything that commits you waits for your press.

## Sources

- MacStories, [OpenAI Unveils Codex "Superapp" Update with Computer Use, Automations, Built-In Browser, and More](https://www.macstories.net/news/openai-unveils-codex-superapp-update-with-computer-use-automations-built-in-browser-and-more/) (April 16, 2026). Windows support for Codex computer use was reported by Thurrott and PCWorld (May 29 and June 2, 2026).
- heise online, [Perplexity brings AI agent with "Portable Computer" to local Nvidia hardware](https://www.heise.de/en/news/Perplexity-brings-AI-agent-with-Portable-Computer-to-local-Nvidia-hardware-11426452.html) (Aug. 26, 2026)
- MacStories, [Anthropic Introduces an In-App Browser for Claude Cowork](https://www.macstories.net/news/anthropic-introduces-an-in-app-browser-for-claude-cowork/) (Aug. 27, 2026)
- [Chrome DevTools Protocol](https://chromedevtools.github.io/devtools-protocol/), [Playwright MCP](https://github.com/microsoft/playwright-mcp), [Browser Use](https://github.com/browser-use/browser-use)

## Frequently asked questions

### What is the difference between browser use and computer use?

Browser use lets an AI agent operate a web browser, usually by reading the page's structure and clicking elements through the browser's automation interface. Computer use lets an agent operate a whole computer by looking at screenshots and controlling the mouse and keyboard, so it can use desktop apps as well as websites. Browser use is faster and more precise on the web. Computer use reaches everything else.

### Is computer use better than browser use?

Not generally. Computer use is more general because it works with any app, but it is slower, uses more tokens per step because it reads images, and is easier to confuse. For websites, browser use is usually more reliable. Use computer use for desktop software that has no API and no web version.

### When should an AI agent use an API instead?

Whenever a good API or connector exists. API calls are fast, cheap, precise and easy to audit, and they don't break when a website redesigns. Agents should prefer APIs or MCP connectors, fall back to browser use for websites without one, and use computer use as the last resort.

### Which AI agents support computer use in 2026?

Anthropic's Claude has offered computer use since 2024. OpenAI's Codex added computer use on Mac in April 2026 and on Windows at the end of May. Perplexity offers Computer and, since August 2026, a local Portable Computer. Agentastic offers computer use alongside browser use and native app integrations on the Mac.

### Is computer use safe?

It carries more risk than browser use because the agent can reach anything on the screen, including apps and files unrelated to the task. Run it in a separate account or virtual machine when possible, keep approvals on for irreversible actions, and avoid leaving sensitive windows open while it works.