Open-Source Browser Automation vs a Managed Multi-Account Browser (2026)

Most automation starts the same way. Someone installs Selenium, Playwright or Puppeteer, writes a script that signs in to a dashboard and exports a report, and it works. Then the job grows. There are ten client accounts instead of one. A teammate needs to look at a session the script left open. Each account needs its own proxy. Cookies need to survive between runs.

At that point the question changes from "which library do I use?" to "who looks after the browser around it?" This post compares two ways to answer that: plain open-source automation, and a managed multi-account browser that your existing scripts attach to.

Everything here assumes automation of your own workflows, in accounts you or your clients own, within each site's terms and robots rules. Neither option changes what a site permits.

Quick Verdict

TL;DR: Plain Selenium, Playwright or Puppeteer is the right choice for one account, a few accounts, one-off jobs and prototypes. It is free, flexible and well documented. A managed multi-account browser earns its place when you run many separate logged-in accounts, need sessions to persist, assign a proxy per account, or want teammates to share profiles. Because scripts attach over CDP, you do not rewrite your workflow when you move; you change how the browser is launched.

The Open-Source Libraries

Selenium

The oldest and widest option, with bindings for most languages. It drives real browsers through WebDriver, and it can attach to an already-running Chromium through a debugger address.

Good at: broad language support, a huge body of examples, cross-browser testing. Less good at: speed and ergonomics next to newer tools, and it leaves browser state management to you.

Playwright

A modern library with auto-waiting, solid tracing and first-class support for several browser engines. It can launch its own browser or attach to a running one with connectOverCDP.

Good at: reliable tests and scripted flows, strong tooling, multiple languages. Less good at: long-lived account state. Persistent contexts exist, but you manage the directories, proxies and cleanup yourself.

Puppeteer

A Node library that drives Chromium over CDP. It launches its own browser or connects to one through a WebSocket endpoint.

Good at: Chromium-centred scripting, screenshots and PDFs, a simple API. Less good at: the same account-state bookkeeping, because each launch is a fresh browser unless you build persistence around it.

What You Build Yourself with Libraries Alone

When you automate many accounts with a library on its own, these become your responsibility:

• Profile storage. Where each account's cookies and local storage live, how they are named, and how they are backed up.
• Proxy assignment. Which account uses which proxy, and keeping that pairing stable.
• Identity settings. Timezone, locale, screen size and the rest, kept consistent per account from one run to the next. "The rest" is a long list, from audio, font and hardware signals to battery, sensor and pointer APIs.
• Concurrency. Making sure two workers never open the same account at once.
• Sharing. Letting a teammate open a session without sharing credentials in a chat message.
• Upkeep. Keeping browser binaries and drivers current as upstream releases ship.

None of this is hard in isolation. Together it becomes a small internal product that somebody has to maintain.

What a Managed Multi-Account Browser Adds

JustBrowser is a multi-account browser for teams. It is built on a custom Chromium engine with native C++ integration rather than as an extension, and it is kept current with upstream Chromium, so a profile's settings come from the engine itself rather than from scripts layered on top. (For how sites read a browser below the page, see our JA4 and TLS fingerprints explainer.)

• Profiles as separate browsers. Each profile has its own cookies, storage, proxy and identity parameters (40+, covering canvas, WebGL, audio, fonts, screen, timezone, navigator and hardware), so accounts you are allowed to hold stay separate.
• Per-profile proxies. HTTP, HTTPS or SOCKS5 per profile. Bring your own or buy a proxy plan in the app.
• Team sharing. Invite teammates for free and share profiles with them. A team seat can run the profiles shared with it; it has no cloud sync of its own profiles, no REST API and no AI features.
• Cloud sync. Profiles can sync between machines.
• REST API and CDP. Start and stop profiles over a local REST API and attach Playwright, Puppeteer or Selenium to the returned cdp_url.
• Headless launch for scripted setups.

It runs on Windows x64 and macOS (Apple Silicon). There is no Linux build and no mobile app, which matters if your automation currently runs on Linux servers.

Feature Comparison

Other multi-account browsers, such as Multilogin, GoLogin and AdsPower, cover similar ground; compare their published pricing and platform support against your needs. Our REST API comparison for developers looks at the API side.

Where Plain Libraries Are the Right Call

One account or a few. If you manage a handful of accounts, a persistent context per account in Playwright may be all you need.

Prototyping. Build the first version of a script with the library alone. Move to a managed browser only if account management becomes the bottleneck.

Linux and CI. Test suites and server-side jobs on Linux cannot use a Windows or macOS desktop browser. Stay with the libraries there.

One-off jobs. An afternoon export does not justify adopting a new tool. Write the script and be done.

Cross-browser testing. If you need Firefox and WebKit coverage, Playwright's built-in engines are the point.

Where a Managed Browser Pays Off

Many accounts, kept apart

An agency working in dozens of client accounts needs each client's sessions separate and reliably restored. Profiles do this by design. The same applies to storefronts you operate on several marketplaces, or QA profiles for different locales and timezones (our ad verification workflow walks through one such setup).

Teams sharing sessions

When a script leaves a session open, a colleague can pick it up from a shared profile instead of re-authenticating. Roles and sharing keep that organised, and seats cost nothing.

Less glue code

Profile directories, proxy wiring and cleanup scripts are the unglamorous part of multi-account automation. Moving them into the product leaves your scripts focused on the workflow itself.

Predictable upkeep

An engine kept current with upstream Chromium means one fewer thing to track. The subscription is a flat $9.99 a month (or $99.99 a year, about 17% below twelve monthly payments), with unlimited profiles. The trial is 7 days, card required, and you are not charged if you cancel inside the week.

Switching Without Rewriting

Your workflow code can stay as it is. Only the launch step changes. Start the profile through the REST API (send {"headless": false} for a visible window, since the API starts headless by default), then attach:

import { chromium } from 'playwright';

const JB_API_TOKEN = process.env.JB_API_TOKEN; // from the app's API/AI tab
const res = await fetch('http://127.0.0.1:36542/api/v1/profiles/PROFILE_ID/start', {
  method: 'POST',
  headers: { 'Authorization': `Bearer ${JB_API_TOKEN}`, 'Content-Type': 'application/json' },
  body: JSON.stringify({ headless: false })
});
const { data: { cdp_url } } = await res.json();

const browser = await chromium.connectOverCDP(cdp_url);
const context = browser.contexts()[0]; // the profile's own context
const page = context.pages()[0] ?? await context.newPage();
// ...your existing workflow...

await fetch('http://127.0.0.1:36542/api/v1/profiles/PROFILE_ID/stop', {
  method: 'POST',
  headers: { 'Authorization': `Bearer ${JB_API_TOKEN}` }
});

Use contexts()[0] rather than creating a new context, which would sit outside the profile. And remember that browser.close() only disconnects; the stop call ends the session. For Selenium, pin ChromeDriver to the engine's current major version, or Selenium Manager may fetch a driver for your machine's own Chrome and the attach fails. The Playwright and Puppeteer walkthrough covers the REST API flow in more detail.

The Hybrid Approach

Plenty of teams use both. Linux CI and one-off jobs stay on the plain libraries. Long-lived, multi-account desktop workflows run through profiles. Because the script code is the same library either way, keeping both costs little.

Recommendation

Start with the library. Install Playwright, Puppeteer or Selenium and see whether it covers your workflow.

Move to a managed browser when:

• you run many separate logged-in accounts
• sessions need to persist and be restored reliably
• each account needs its own proxy
• several people need to share sessions
• the glue code around profiles is taking more time than the workflow

The 7-day trial includes unlimited profiles and the REST API. Point one of your existing scripts at a profile and see how much code you can delete.

Frequently Asked Questions

Can plain Selenium, Playwright or Puppeteer handle my workflow?

Often, yes. If your workflow runs against one account, or a handful, and a fresh browser each run is fine, the open-source libraries are free, well documented and enough. They start to feel thin when you need many separate logged-in accounts, persistent sessions, per-account proxies or teammates sharing the same sessions.

What does a multi-account browser add on top of an automation library?

It manages the browser itself. Each profile is its own browser with its own cookies, storage, proxy and identity parameters, kept between sessions, and your Playwright, Puppeteer or Selenium script attaches to it over CDP. You keep writing the workflow in the library you already use.

When should I move from open-source tooling to a managed browser?

When the time spent building and maintaining profile storage, proxy assignment, session persistence and sharing starts to exceed the subscription cost, or when several people need to work in the same sessions. For a one-off job or a single account, stay with the library.

How do I connect my existing script to JustBrowser?

Start a profile through the local REST API, which returns a cdp_url. Attach with Playwright's connectOverCDP, Puppeteer's connect, or Selenium's debugger address, use the first context, and stop the profile through the API when you are done.

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Try JustBrowser

A multi-account browser for teams, built on a custom Chromium engine with native C++ integration, not an extension. 40+ identity parameters, local REST API and CDP for Playwright, Puppeteer and Selenium. Windows x64 and macOS (Apple Silicon). 7-day free trial, card required — then $9.99/month or $99.99/year, unlimited profiles, free team seats.

Get started → · How it differs from Multilogin / GoLogin / AdsPower