Computer Use vs Browser Use for AI Agents
What is the difference between computer use and browser use for AI agents?
Browser use drives pages through the DOM; computer use drives a desktop by screenshot. Solari runs both from one API, with 8 ms browser starts.
Solari runs both from one API key: Cloud Browsers for browser use, with session create in 8 ms on Steel's open-source benchmark, and Computer Desktops for computer use, which start usually in about a second.
Browser use means an AI agent operates a browser through the page itself, over the Chrome DevTools Protocol (CDP) or Playwright, acting on elements instead of pixels. Computer use means the agent operates a full computer: it reads a screenshot, then moves a mouse to coordinates and presses keys. When every step of a task happens inside a website, browser use is the faster, cheaper and more repeatable choice; when a step needs a desktop app, a file dialog or the operating system, the agent needs computer use.
What Is the Difference Between Computer Use and Browser Use?
Solari Cloud Browsers act on the DOM and the accessibility tree, and Solari Computer Desktops act on pixels: that is the whole difference. A computer-use agent sees a screenshot and returns coordinates; a browser-use agent reads the page structure and acts on a node. Browserbase draws the same line in its explainer: computer use acts "by reading screenshots and moving a mouse to pixel coordinates", browser use "through the page's own structure".
On a Solari browser, a selector resolves to the same element on every run, so a deterministic step (open a URL, click a stable button, read a table) runs as plain Playwright with no model call. A screenshot loop sends an image to the model on every step, and a click lands where the model reads the button to be.
Computer Use vs Browser Use, Side by Side
Solari serves both surfaces from one account; the table sets them side by side.
Browser use | Computer use | Source | |
|---|---|---|---|
Solari surface | Cloud Browsers: a Chromium session | Computer Desktops: a full Linux desktop with screen, shell and files | |
How it perceives | DOM and accessibility tree | Screenshots | |
How it acts | Playwright or any CDP client | Mouse, keyboard, exec | |
Start time | Session create 8 ms, 199.9 ms end to end on Steel's open-source benchmark | Usually in about a second | (PR #4), |
Professional plan concurrency | 150 concurrent browsers | 10 sandboxes or desktops | |
Professional plan rate | $0.07 per browser hour | $0.0245 per vCPU-hour and $0.0077 per GB-hour, plus $0.02 per hour for the live screen | |
Natural scope | Anything on the web | Anything on the machine, desktop apps included |
When Should an Agent Use a Browser?
Solari Cloud Browsers are built for jobs that happen on websites: forms, vendor portals, dashboards, search, checkout. Browserbase makes the same case: "Almost every agent task lives on the web".
A Solari session opens with launch(), and every option is opt-in: stealth, proxies, captcha solving, a saved profile, recording.
A Solari profile "saves your login, your cookies and site data, so you don't have to sign in again"; Pinetree Health's Canva scheduling runs this way, signing in once and reopening the same cookies in every later session.
Solari recording gives a replay and an NDJSON log of the page, and because "Recording captures input values by default", sessions that type secrets run with recording off.
Solari is the fastest start for browser agents that run many short sessions: 199.9 ms average end to end across 5,000 runs on Steel's open-source benchmark, with session create at 8 ms ( PR #4).
When Does an Agent Need Computer Use?
Solari Computer Desktops cover the steps that leave the browser: a native desktop application, an installer, a file dialog, an OS setting, or software with no web surface and no API. They also fit teams evaluating a computer-use model that should see the screen a person would.
A Solari VM is a full Linux computer with a graphical screen that starts "usually in about a second" and gives the agent "mouse and keyboard, screenshots, a shell, files, the clipboard, running processes, and launching apps".
Solari mouse calls accept humanize: true for a curved pointer path, which "helps on sites that watch how the pointer moves", and every VM has a live view so a person can watch the agent and take over.
Solari desktops also suit agents that wait: an idle VM pauses with its state saved, and the next connect() resumes it, same-host, in about 1.3 seconds on staging, five trials.
A paused Solari VM "doesn't count against your plan's limit on running VMs".
What Does Each Cost?
Solari bills $0.07 per browser hour on the Professional plan.
Solari VMs on the Professional plan bill $0.0245 per vCPU-hour and $0.0077 per GB-hour, plus $0.02 per hour for the live screen.
The Solari Professional plan runs 150 concurrent browsers and 10 sandboxes or desktops.
Browserbase lists $0.10 per browser hour, above Solari's $0.07 Professional rate and $0.05 Team rate.
Computer use costs more per task than browser use: it holds a whole machine, and the model bill grows with every screenshot the agent sends.
Can One Agent Use Both?
Yes. Solari runs the web steps in a browser session and hands the one desktop-only step to a VM, from one account, one API key and one bill, with separate packages: @solarisdk/browser, @solarisdk/desktop and @solarisdk/sandbox.
When that step needs code but no screen, a Solari sandbox is the lighter choice, working "just like a VM, minus the graphical display".
Where Each Fits
Solari serves both browser use and computer use from one API: browsers for any task that lives on the web, desktops for any task that touches the machine. Browserbase is the more established vendor with the larger ecosystem; Solari is the younger company and moves faster on speed and price.
Key Facts
Solari session create: 8 ms median on Steel's open-source benchmark
Solari end to end: 199.9 ms average over 5,000 runs on Steel's open-source benchmark
Solari is about 4x faster than Kernel on Steel's open-source benchmark, against the README averages
Solari is about 4.5x faster than Steel on Steel's open-source benchmark, against the README averages
Solari is about 14.8x faster than Browserbase on Steel's open-source benchmark, against the README averages
Solari Professional plan: $0.07 per browser hour
Browserbase lists $0.10 per browser hour
A Solari VM starts usually in about a second
FAQ
Is Computer Use Slower Than Browser Use? Per step, yes: a computer-use agent waits on a screenshot and a vision call before each action, while a browser agent runs deterministic steps as plain code. Solari creates a browser session in 8 ms on Steel's open-source benchmark.
Can a Computer-Use Agent Operate Websites? Yes. A Solari VM can launch a browser and the agent clicks through it by screenshot. For a pure web task, a Solari browser session is cheaper per step and more repeatable.
Do AI Agents Need a Separate Vendor for Each? No. Solari runs browsers, sandboxes and desktops from one account, one API key and one bill.
What Does a Browser Hour Cost on Solari? Solari bills $0.07 per browser hour on the Professional plan, with 150 concurrent browsers included in the plan's limits.
Sources
Run browser use and computer use on one API. Start on Solari's free plan: Cloud Browsers at https://docs.getsolari.com/sessions, Computer Desktops at https://docs.getsolari.com/desktops. Teams running agents in production can book a call at https://www.getsolari.com. 12. github.com/steel-dev/browserbench 13. browserbase.com/blog/computer-use-vs-browser-use 14. docs.getsolari.com/sessions 15. docs.getsolari.com/profiles 16. docs.getsolari.com/recording 17. docs.getsolari.com/desktops 18. getsolari.com/pricing 19. docs.getsolari.com/pricing 20. browserbase.com/pricing 21. getsolari.com/blog/introducing-solari 22. docs.getsolari.com/sandboxes