What is Browserbase and why do AI agents need it?

Browserbase is a managed headless Chrome infrastructure service founded in 2023, with a $300M Series B valuation (2025) and over 50 million browser sessions processed in 2025. AI agents need real browsers because modern websites are JavaScript-heavy SPAs (React, Next.js, Vue) that return empty HTML to simple HTTP requests -- the content renders dynamically after page load. AI agent frameworks like Browser Use, Stagehand, LangChain, and Playwright MCP all require a Chrome runtime to execute actions (click, type, scroll) and observe results (DOM, screenshots). Running Chrome locally is resource-intensive (500MB+ RAM per session, complex driver management, crash recovery), so Browserbase provides Chrome-as-a-service: a CDP WebSocket endpoint your agent connects to, with Chrome running in Browserbase's cloud. This eliminates the DevOps burden of Chrome infrastructure while providing built-in stealth, session recording, and regional deployments (US-East, US-West, EU-West).

Why combine Browserbase with Coronium mobile proxies instead of using Browserbase alone?

Browserbase's default egress IPs come from their cloud infrastructure -- Google Cloud and AWS ranges that anti-bot systems identify via ASN lookup as datacenter origin. On targets protected by Cloudflare, DataDome, Akamai, or PerimeterX, default Browserbase traffic scores 60-75% success. Adding Coronium mobile proxies via the BYOP (Bring Your Own Proxy) feature routes traffic through CGNAT-backed carrier IPs (T-Mobile, AT&T, Vodafone, Jio) which have the highest trust scores in anti-bot reputation systems. The combination of Browserbase's authentic Chrome fingerprints (TLS, HTTP/2, Canvas, WebGL) at the browser layer and Coronium's CGNAT-backed mobile IPs at the network layer addresses the two detection axes that matter most. Result: 90-95% success rates on LinkedIn, Amazon, Google, booking sites, and financial portals that reject default Browserbase traffic.

How do I configure Coronium mobile proxies with Browserbase in Node.js?

Install @browserbasehq/sdk and playwright-core via npm. Import Browserbase and initialize with your API key. Call bb.sessions.create() with a proxies array containing your Coronium endpoint: proxies: [{ type: "external", server: "http://mobile-ip.coronium.io:port", username: "your_user", password: "your_pass" }]. Include stealth: true and region: "us-east-1" (match to proxy country). The API returns a connectUrl. Pass it to playwright.chromium.connectOverCDP(connectUrl) to get a browser instance. Create a context and page as usual -- all traffic routes through the Coronium proxy automatically. For keepAlive sessions, set keepAlive: true to preserve state across multiple API calls. Handle reconnection with try/catch around CDP operations and implement exponential backoff on WebSocket disconnects.

How do I configure Coronium proxies with Browserbase in Python?

Install the browserbase Python SDK (pip install browserbase) and playwright (pip install playwright). Import Browserbase and create a client: bb = Browserbase(api_key="your_api_key"). Create a session: session = bb.sessions.create(project_id="proj_id", proxies=[{"type": "external", "server": "http://mobile-ip.coronium.io:port", "username": "your_user", "password": "your_pass"}], stealth=True, region="us-east-1"). Use playwright.sync_api to connect: with sync_playwright() as p: browser = p.chromium.connect_over_cdp(session.connect_url). Create context and page, then navigate normally. All traffic flows through the Coronium proxy. For async agents using async_playwright(), connect with await p.chromium.connect_over_cdp(session.connect_url). Both sync and async patterns work identically with Coronium.

How do I integrate Browserbase + Coronium with Browser Use framework?

Browser Use is an LLM-driven browser automation framework with 50K+ GitHub stars. Install via pip install browser-use. Create a Browserbase session with Coronium proxy config as shown above, obtain the connect_url, then pass it to Browser Use via the Browser class: from browser_use import Browser, Agent. browser = Browser(cdp_url=session.connect_url). agent = Agent(task="Find the price of AirPods Pro on Amazon and return the number.", llm=ChatOpenAI(model="gpt-4"), browser=browser). Run with await agent.run(). Browser Use's LLM plans actions, Browserbase executes them in managed Chrome, and Coronium routes network traffic through CGNAT mobile IPs. The same pattern works with Claude (via langchain_anthropic), Gemini (via langchain_google_genai), and local models (via langchain_ollama).

What is the correct Browserbase region for my Coronium proxy country?

Match Browserbase region to Coronium proxy country for minimum latency and consistent geolocation signals. For US Coronium proxies (T-Mobile, AT&T, Verizon), use region: "us-east-1" (Virginia) or "us-west-2" (Oregon) depending on proxy state -- East Coast proxies with us-east-1, West Coast with us-west-2. For European Coronium proxies (UK, Germany, France, Spain, Netherlands, Italy), use region: "eu-west-1" (Ireland). Mismatches create detectable latency patterns: a Browserbase US-East session through a German proxy has 80-120ms Virginia-to-Frankfurt RTT that real German mobile users don't experience. Anti-bot systems analyze these timing anomalies. For agents targeting multiple geographies, create parallel Browserbase sessions per region rather than routing cross-region. Browserbase session creation is under 2 seconds, so per-region sessions are not a performance bottleneck.

Does Browserbase's stealth mode replace the need for mobile proxies?

No -- Browserbase stealth mode and mobile proxies address different detection layers. Stealth mode patches browser-level indicators: navigator.webdriver, window.chrome, Canvas/WebGL fingerprints, plugin lists, and CDP artifacts. This fixes the "is this a real Chrome?" signal. Mobile proxies fix the "is this a real user?" signal through IP reputation. Anti-bot systems like Cloudflare, DataDome, and Akamai score requests on both axes independently. A stealth browser from a flagged datacenter IP still scores low because of IP reputation. A real browser without stealth from a mobile IP still scores low because of browser fingerprint leaks. You need both: Browserbase stealth + Coronium mobile. On Cloudflare Turnstile specifically, stealth alone passes ~60% of the time, mobile IP alone passes ~70%, combined stealth + mobile passes 90-95%. The two are multiplicative, not redundant.

What are Browserbase pricing tiers and how does Coronium cost compare?

Browserbase has three pricing tiers as of April 2026: Free tier (1,000 sessions/month, limited features, no SLA), Startup tier ($39/month base + usage-based overage), and Scale tier (custom pricing for enterprise workloads with SLA and dedicated support). Session-minute pricing applies on top of base fees. Coronium mobile proxies are priced per dedicated device with unlimited bandwidth starting from $27/month. There are no per-GB charges, no session limits, and no surprise overages -- you pay a fixed monthly rate per mobile device. For a typical AI agent workload processing 100,000 pages/month, combined costs are approximately $39 (Browserbase Startup) + $27-100 (Coronium, 1-4 devices) = $66-139/month, significantly cheaper than per-GB residential proxies at the same traffic level ($200-500+/month) and with higher success rates on protected targets.

How do I debug when AI agents fail on Browserbase + Coronium?

Browserbase provides full session recording including DOM snapshots, network requests, console logs, and video replay. Access recordings via the Browserbase dashboard or the sessions.retrieve() API. When agents fail, replay the session to see exactly what the agent saw: was the page blocked by Cloudflare? Did a CAPTCHA appear? Did a target element change selectors? Combine with Coronium's per-device connection logs to diagnose the failure layer. Failures fall into three categories: (1) Agent reasoning errors (LLM picked wrong action) -- fix in the prompt or LLM choice, (2) Browser errors (element not found, timeout) -- fix with better selectors or longer waits, (3) Network errors (403, 429, Cloudflare block) -- fix with different Coronium proxy or better rotation strategy. The session recording shows which category you're in. For production agents, tag sessions with userMetadata: { agent_run_id, proxy_device, target } for filterable analytics across thousands of runs.

Can I use Browserbase + Coronium for scraping vs just AI agents?

Yes -- Browserbase + Coronium works for any browser automation task, not just LLM-driven agents. Traditional web scraping with Playwright or Puppeteer benefits from the same combination: managed Chrome infrastructure eliminates DevOps overhead, CGNAT mobile IPs bypass anti-bot detection. The main difference is cost-effectiveness: for high-volume static scraping where you're making millions of requests, a self-hosted Scrapy cluster with Coronium proxies is cheaper because you're not paying per session-minute. For moderate-volume, high-difficulty scraping (LinkedIn profiles, Amazon products, Google SERPs) where session count is in the thousands rather than millions, Browserbase + Coronium is cheaper than self-hosting because you avoid the infrastructure cost. The crossover point is roughly 500K-1M page requests/month. Below that, Browserbase + Coronium wins on total cost of ownership. Above that, self-hosted Scrapy + Coronium proxies wins.

What are the advantages of Stagehand over raw Playwright + Browserbase?

Stagehand is Browserbase's own TypeScript/Python SDK that adds three LLM-powered methods on top of Playwright: act() takes a natural language instruction ("click the sign-in button") and resolves it to a Playwright action. extract() takes a schema and returns typed structured data from the current page. observe() returns a list of actionable elements the agent can interact with. The advantage over raw Playwright is resilience to DOM changes -- if Amazon changes their "Add to Cart" button selector tomorrow, act("add the product to the cart") still works because Stagehand uses vision + LLM to find the element. Raw Playwright scripts break on every DOM change. For agentic workflows, Stagehand reduces code by 50-70% and reduces maintenance burden dramatically. The trade-off is LLM cost per action (~$0.001-0.01 per act() call) and 1-3 seconds latency per LLM-resolved action. For production agents, Stagehand + Browserbase + Coronium is the recommended stack.

How do I rotate Coronium mobile IPs across Browserbase sessions?

Coronium provides two rotation mechanisms: (1) API-triggered rotation -- call the Coronium rotation endpoint (https://api.coronium.io/rotate/{device_id}) to force a new carrier-assigned IP. Typical rotation completes in 5-15 seconds. (2) Time-based rotation -- configure auto-rotation intervals (5, 10, 30 minutes) in the Coronium dashboard. For Browserbase integration, trigger rotation between sessions rather than mid-session, since the Browserbase CDP connection caches the proxy IP at session creation. Pattern: create a Browserbase session with Coronium proxy, run agent task, terminate session, call Coronium rotation API, create new session with fresh IP, repeat. For concurrent agent workloads, use multiple Coronium devices in parallel rather than rotating a single device. Each device maintains its own carrier-assigned IP, so N devices provide N concurrent fresh IPs. Pool device assignments across your session pool with a round-robin allocator.

Does Browserbase + Coronium work with MCP (Model Context Protocol)?

Yes -- MCP's Playwright server accepts any CDP WebSocket URL, including Browserbase endpoints. Configure the MCP server with your Browserbase connect URL, and the MCP browser tools (navigate, click, extract, screenshot) execute in Browserbase with Coronium proxy routing. In Claude Desktop, add the Playwright MCP to claude_desktop_config.json with the Browserbase URL as the connection target. For Anthropic's Agent SDK, use the mcp_servers parameter to register the Playwright server. The agent's tool calls translate to CDP commands against Browserbase. This pattern works with Claude (Anthropic), GPT (via MCP bridge), and Gemini (via MCP support in Gemini 2.5+). MCP is the standardized agent tool protocol across providers, so Browserbase + Coronium + MCP gives you a provider-agnostic agentic browser stack. Session recordings and Coronium device logs provide the same debugging surface as raw SDK integrations.

What happens if my Coronium proxy rotates mid-Browserbase session?

If a Coronium mobile IP rotates while a Browserbase session is active (for example, carrier NAT timeout, tower handoff, or scheduled rotation), the CDP WebSocket connection remains open because it terminates at the Browserbase proxy layer, not the Coronium proxy layer. However, subsequent browser requests will use the new IP. Target sites may detect the IP change within a session as suspicious (session cookies established from IP A, next request from IP B). Best practices: (1) Set Coronium rotation interval longer than your agent's task duration -- 30-minute rotation for 20-minute tasks. (2) Create short-lived Browserbase sessions (one per agent task) rather than long-lived keepAlive sessions when using rotating mobile IPs. (3) If you need long-lived sessions, use Coronium's "sticky session" mode which maintains the same IP for up to 60 minutes. (4) Monitor for 403/429 responses after rotation events and implement session recreation logic.

AI Agent Infrastructure -- Updated April 2026

Browserbase Proxy Setup Guide

Browserbase processed 50M+ browser sessions in 2025 and raised a $40M Series B at a $300M valuation. It's the infrastructure layer behind Browser Use, Stagehand, and most serious AI agent frameworks. Combine it with Coronium mobile proxies via BYOP to achieve 90-95% success rates on Cloudflare-protected targets.

This guide covers step-by-step integration with Node.js and Python code examples, Browser Use framework integration, session configuration (stealth, regions, proxy rotation), and troubleshooting for auth failures, DNS leaks, and region mismatches.

Fact-checked: Statistics cite Browserbase funding announcements, session count disclosures, and API documentation (April 2026)

Managed Chrome

AI Agent Ready

Node.js + Python

Stealth Mode

BYOP Integration

3 Regions

50M+

Browser sessions processed (Browserbase, 2025)

$300M

Browserbase Series B valuation (2025)

1K/mo

Free tier sessions on Browserbase

95%+

Mobile proxy success on AI agent tasks

What this guide covers:

Browserbase infrastructure overview

Coronium BYOP integration (Node.js + Python)

Session config: stealth, regions, keepAlive

Browser Use framework integration

Troubleshooting auth, DNS, region issues

Pricing comparison with alternatives

Table of Contents

10 Sections

Navigate This Guide

End-to-end reference for integrating Coronium mobile proxies with Browserbase, from setup to production debugging.

1. What is Browserbase?

2. Why Browserbase + Coronium

3. Setup Step-by-Step

4. Session Configuration

5. Browser Use Integration

6. Common Issues & Fixes

7. Pricing Comparison

8. Frequently Asked Questions

9. Coronium Pricing

10. Related Resources

Reading time: ~18 minutes. Includes working Node.js and Python code you can paste into your agent project.

AI frameworks

Issues + fixes

FAQ answers

Infrastructure Overview

What is Browserbase?

Browserbase is a managed headless Chrome infrastructure company founded in 2023. It provides Chrome-as-a-service for AI agents and browser automation, eliminating the DevOps burden of running Chrome at scale.

Company Snapshot (April 2026)

Based on public funding and product announcements

Founded: 2023
Valuation: $300M (Series B, $40M raised in 2025)
Sessions processed: 50M+ browser sessions in 2025
Headquarters: San Francisco, California
Protocol support: Playwright, Puppeteer, Selenium (CDP)
Regions: US-East (Virginia), US-West (Oregon), EU-West (Ireland)
SDKs: Node.js (@browserbasehq/sdk), Python (browserbase)

Why AI Agents Use Browserbase

The Chrome infrastructure problem solved

AI agents need a real browser to interact with modern websites. Over 60% of the web is JavaScript-heavy SPAs (React, Next.js, Vue) that return empty HTML to HTTP-only requests. Running Chrome locally is resource-intensive: 500MB+ RAM per session, complex driver management, crash recovery, binary updates, and session cleanup.

Browserbase abstracts all of this. Your agent gets a CDP WebSocket URL. Chrome runs in Browserbase's cloud. Sessions spin up in under 2 seconds, scale to thousands of concurrent browsers, and terminate automatically when idle. It's the S3-for-Chrome of AI agent infrastructure -- used by Browser Use, Stagehand, and most production AI agent frameworks.

Managed Headless Chrome

Fully-managed Chrome infrastructure running in isolated cloud containers. No local browser binaries, no driver management, no Docker images. Sessions spin up in under 2 seconds and auto-terminate when idle, scaling to thousands of concurrent browsers without provisioning servers.

Protocol Compatibility

Exposes the Chrome DevTools Protocol (CDP) endpoint over WebSocket. Any Playwright, Puppeteer, or Selenium script that connects via CDP works without code changes. Browserbase is a drop-in replacement for local Chromium in CI pipelines and AI agent frameworks.

Stealth Browser Mode

Built-in anti-detection features including navigator.webdriver patching, Canvas/WebGL fingerprint randomization, realistic hardware concurrency, and CDP artifact suppression. Stealth mode is enabled with a single flag at session creation.

Bring Your Own Proxy (BYOP)

Native support for external proxy endpoints via the proxies array in the session creation API. Accepts HTTP and SOCKS5, supports authentication, and routes all browser traffic through your chosen IP. Essential for Coronium mobile proxy integration.

Regional Deployments

Sessions available in US-East (Virginia), US-West (Oregon), and EU-West (Ireland). Match your Browserbase region to your Coronium mobile proxy region to minimize latency and avoid DNS-based geolocation inconsistencies.

Session Recording & Replay

Every session is recorded with full DOM snapshots, network requests, and console logs. Replay failed agent runs in the Browserbase dashboard to debug interaction sequences. Invaluable when AI agents make unexpected decisions mid-task.

AI Agent Ecosystem Adoption

As of April 2026, Browserbase is the default or recommended runtime for Browser Use (50K+ GitHub stars), Stagehand (Browserbase\'s own SDK), Anthropic\'s Claude Computer Use reference implementations, OpenAI\'s Operator infrastructure patterns, LangChain\'s PlayWrightBrowserToolkit, and most Playwright-based MCP servers. If you are building AI agents that need to interact with web UIs, you are almost certainly going to run into Browserbase.

The Combo

Browserbase + Coronium: Why This Combo Works

Browserbase solves the Chrome infrastructure problem. Coronium solves the IP trust problem. Together, they give AI agents the two properties anti-bot systems score on: authentic browser fingerprints and trusted network origin.

CGNAT Trust + Managed Chrome

Browserbase provides authentic Chrome TLS and HTTP/2 fingerprints at the browser layer. Coronium provides CGNAT-backed mobile IPs at the network layer. The combination delivers the two detection axes that matter most: network reputation and browser authenticity.

No Infrastructure to Manage

Browserbase handles Chrome, memory limits, session cleanup, and crash recovery. Coronium handles mobile modem farms, carrier rotation, and IP freshness. Your code only handles business logic -- no Docker, no Kubernetes, no SIM card maintenance.

Scales with Agent Load

Browserbase scales from 1 session to 1,000 concurrent sessions automatically. Coronium mobile proxies handle elastic traffic with unlimited bandwidth per device. The combined stack scales with your AI agent workload without capacity planning.

Session Recording for Agent Debugging

When AI agents fail, Browserbase's session replay shows exactly what the agent saw. Combined with Coronium's per-device connection logs, you can diagnose whether failures originated at the agent reasoning layer, browser layer, or network layer.

Higher Success on Hard Targets

LLM agents often target Google, LinkedIn, Amazon, and booking sites protected by Cloudflare, DataDome, and Akamai. Browserbase stealth mode alone scores 60-75% on these; adding Coronium mobile IPs pushes success rates to 90-95% by fixing the IP reputation signal.

Predictable Pricing at Scale

Browserbase pricing is per session-minute. Coronium pricing is per dedicated device with unlimited bandwidth. Neither has per-GB charges or surprise overage fees, making total cost predictable for agent operations running 24/7.

The Two Detection Axes Anti-Bot Systems Score

Cloudflare, DataDome, Akamai, and PerimeterX all combine these two independent signals

Axis 1: Browser Authenticity

Does this request come from a real Chrome? Signals include TLS fingerprint (JA3/JA4), HTTP/2 SETTINGS frames, Canvas/WebGL rendering output, navigator.webdriver flag, plugin list, and hardware concurrency values.

Browserbase solves this: managed Chrome with stealth patches produces authentic signals.

Axis 2: Network Trust

Does this request come from a trusted network origin? Signals include ASN (datacenter vs ISP vs carrier), IP reputation (historical behavior), geolocation consistency, and CGNAT shared-address patterns.

Coronium solves this: CGNAT-backed mobile IPs from real carriers (T-Mobile, Vodafone, Jio).

Success Rate Math

Local Chrome + Datacenter IP

30-45%

Browserbase only

60-75%

Browserbase + Residential

75-85%

Browserbase + Coronium Mobile

90-95%

* Measured on Cloudflare Turnstile and DataDome-protected targets. Success rates compound multiplicatively -- browser stealth + network trust is the winning combination.

Integration Guide

Setup Step-by-Step: Node.js and Python

Paste-ready code to integrate Coronium mobile proxies with Browserbase via the BYOP (Bring Your Own Proxy) feature. Works with any Playwright or Puppeteer-based agent framework.

Prerequisites

From Browserbase:

Browserbase account (free tier or paid)
API key (from dashboard Settings)
Project ID (from dashboard)

From Coronium:

Mobile proxy device (from $27/month)
Endpoint: mobile-ip-XX.coronium.io:port
Username and password (from dashboard)

Node.js: Browserbase + Coronium Integration

Creates a Browserbase session with Coronium mobile proxy routing, connects via Playwright CDP, and navigates to a target

// Install dependencies

// npm install @browserbasehq/sdk playwright-core

import Browserbase from '@browserbasehq/sdk';

import { chromium } from 'playwright-core';

const bb = new Browserbase({

apiKey: process.env.BROWSERBASE_API_KEY,

});

async function runAgent() {

// 1. Create Browserbase session with Coronium mobile proxy

const session = await bb.sessions.create({

projectId: process.env.BROWSERBASE_PROJECT_ID,

proxies: [{

type: 'external',

server: 'http://mobile-ip-us.coronium.io:PORT',

username: process.env.CORONIUM_USERNAME,

password: process.env.CORONIUM_PASSWORD,

}],

browserSettings: {

stealth: true,

fingerprint: {

locale: 'en-US',

timezone: 'America/New_York',

}

region: 'us-east-1',

keepAlive: false,

});

// 2. Connect Playwright to Browserbase via CDP

const browser = await chromium.connectOverCDP(session.connectUrl);

const context = browser.contexts()[0];

const page = await context.newPage();

// 3. Traffic now routes through Coronium mobile IP

await page.goto('https://example.com', { timeout: 60000 });

const title = await page.title();

console.log('Page title:', title);

// 4. Clean up

await browser.close();

}

runAgent().catch(console.error);

Key points: The proxies array with type: "external" activates BYOP mode. Browserbase routes all page traffic through your Coronium endpoint. stealth: true enables automation indicator patches. region: "us-east-1" should match your proxy country (US mobile IP + Virginia region for lowest latency).

Python: Browserbase + Coronium Integration

Equivalent Python implementation using the browserbase SDK and playwright.sync_api

# Install dependencies

# pip install browserbase playwright

# playwright install chromium

import os

from browserbase import Browserbase

from playwright.sync_api import sync_playwright

bb = Browserbase(api_key=os.environ["BROWSERBASE_API_KEY"])

def run_agent():

# 1. Create Browserbase session with Coronium proxy

session = bb.sessions.create(

project_id=os.environ["BROWSERBASE_PROJECT_ID"],

proxies=[{

"type": "external",

"server": "http://mobile-ip-us.coronium.io:PORT",

"username": os.environ["CORONIUM_USERNAME"],

"password": os.environ["CORONIUM_PASSWORD"],

}],

browser_settings={

"stealth": True,

"fingerprint": {

"locale": "en-US",

"timezone": "America/New_York",

}

region="us-east-1",

keep_alive=False,

)

# 2. Connect Playwright to Browserbase via CDP

with sync_playwright() as p:

browser = p.chromium.connect_over_cdp(session.connect_url)

context = browser.contexts[0]

page = context.new_page()

# 3. Traffic routes through Coronium mobile IP

page.goto("https://example.com", timeout=60000)

print("Page title:", page.title())

browser.close()

if __name__ == "__main__":

run_agent()

Async version: Use async_playwright() and await p.chromium.connect_over_cdp(session.connect_url). Browser Use and Stagehand use async patterns by default.

.env File Template

Store all credentials in environment variables. Never hardcode API keys or proxy credentials in source code.

# Browserbase

BROWSERBASE_API_KEY=bb_live_xxxxxxxxxxxxx

BROWSERBASE_PROJECT_ID=proj_xxxxxxxxxxxxx

# Coronium Mobile Proxy

CORONIUM_USERNAME=your_username

CORONIUM_PASSWORD=your_password

CORONIUM_ENDPOINT=mobile-ip-us.coronium.io:PORT

Session Config

Session Configuration: Stealth, Regions, Rotation

Browserbase session creation accepts a rich config object. These are the options that matter most for Coronium mobile proxy integration and AI agent workflows.

stealth: true

Enables Browserbase's full stealth suite -- navigator.webdriver patched, Canvas/WebGL fingerprint randomization, CDP artifact suppression, realistic navigator.plugins values. Should be enabled for every agent run targeting protected sites.

proxies: [Coronium config]

Array of proxy endpoints. Each entry contains type (external), server (your Coronium endpoint), username, and password. Browserbase routes all page traffic including WebSockets, XHR, and subresources through this proxy.

region: "us-east-1"

Datacenter region for the Chrome session. Options: us-east-1 (Virginia), us-west-2 (Oregon), eu-west-1 (Ireland). Match region to your Coronium proxy country for minimum latency and consistent geolocation signals.

keepAlive: true

Keeps the session alive across multiple API calls. Useful for agent loops that need to preserve cookies, localStorage, and browser state between LLM reasoning steps. Automatically terminates after 30 minutes of inactivity.

fingerprint: { ... }

Advanced fingerprint customization including locale, timezone, screen resolution, and user agent. Set these to match the expected profile of your Coronium mobile IP country -- US mobile IP + en-US locale + America/New_York timezone.

userMetadata: { ... }

Tags attached to the session for dashboard filtering. Use to label sessions by agent run ID, proxy device, or target site. Enables bulk analysis of agent performance across proxy configurations.

Region Matching: Browserbase + Coronium

Match Browserbase region to Coronium proxy country for minimum latency and consistent geolocation signals

Coronium Proxy Country	Browserbase Region	Suggested Locale	Suggested Timezone	Latency
United States (East Coast)	us-east-1	en-US	America/New_York	<20ms
United States (West Coast)	us-west-2	en-US	America/Los_Angeles	<20ms
United Kingdom	eu-west-1	en-GB	Europe/London	<30ms
Germany	eu-west-1	de-DE	Europe/Berlin	<30ms
France	eu-west-1	fr-FR	Europe/Paris	<30ms
Spain	eu-west-1	es-ES	Europe/Madrid	<30ms
Netherlands	eu-west-1	nl-NL	Europe/Amsterdam	<30ms
Italy	eu-west-1	it-IT	Europe/Rome	<30ms

* Latency is Browserbase-to-Coronium round-trip time. Cross-region routing (e.g., EU proxy with US Browserbase region) adds 80-150ms and creates detectable timing anomalies.

Proxy Rotation Strategies

One task, one session

Create Browserbase session per agent task. Terminate after. Trigger Coronium rotation between tasks. Best for independent tasks.

Long-lived agent loop

Use keepAlive: true + Coronium sticky session (60 min). Rotate on schedule, not per-task. Best for multi-step workflows.

Concurrent agent fleet

N agents = N Coronium devices + N parallel Browserbase sessions. Round-robin device allocation. No shared state.

High-failure target

Rotate Coronium IP on every 403/429. Immediate session recreation with fresh proxy. Track per-IP success rate.

Stealth Configuration Best Practices

Always set stealth: true

Browserbase stealth patches navigator.webdriver, Canvas, WebGL, plugins. Free feature. No reason to disable.

Match fingerprint.locale to proxy country

en-US for US proxy, de-DE for German, etc. Locale-country mismatch is an instant red flag.

Match fingerprint.timezone to proxy country

America/New_York for US East, Europe/Berlin for Germany. JavaScript can read Intl timezone.

Use userMetadata for tagging

Tag sessions with agent_run_id, target_site, proxy_device for filterable analytics.

Enable dnsOverHttps when available

Prevents DNS leak where browser resolves DNS locally outside the proxy.

AI Agent Frameworks

Integration with Browser Use and AI Agent Frameworks

Browserbase + Coronium plugs into every major AI agent framework via the CDP WebSocket endpoint. Here are the six frameworks where this integration is most common.

Browser Use

50K+ GitHub stars -- Python

LLM-driven browser automation framework from Magnus Muller and the Browser Use team. Takes a natural language task and generates browser actions step-by-step. Widely adopted for autonomous web agents. Supports GPT-4, Claude 4.6, and Gemini models for action planning.

Integration: Browser Use connects to Browserbase via the CDP WebSocket endpoint. The agent loop runs locally while browser execution happens in Browserbase. Proxy routing is inherited from the Browserbase session config.

Best for: Autonomous web agents, form-filling bots, research agents, e-commerce checkout automation

Stagehand

Browserbase-maintained -- TypeScript, Python

Browserbase's own AI browser automation SDK. Extends Playwright with three LLM-powered methods: act() for natural language actions, extract() for structured data extraction, and observe() for element discovery. Optimized for Browserbase's infrastructure.

Integration: Native Browserbase integration -- Stagehand creates sessions automatically and accepts a proxies config at initialization. Inherits all BYOP capabilities including Coronium mobile proxy routing.

Best for: Agentic workflows needing both deterministic code and LLM-driven steps, production AI products

LangChain + Playwright

90K+ GitHub stars (LangChain) -- Python, JavaScript

LangChain's built-in PlayWrightBrowserToolkit wraps Playwright in LangChain tools. Agents built with LangGraph or LangChain agents can navigate, click, extract, and screenshot through the toolkit. Runs against local Chromium or remote CDP endpoints.

Integration: Point LangChain's playwright.chromium.connect_over_cdp() at a Browserbase session URL. Session-level proxy config is applied automatically.

Best for: Multi-step agent workflows, tool-using LLM chains, agent memory integration

Playwright MCP

Anthropic MCP standard -- TypeScript, Python

Model Context Protocol servers expose Playwright as tools for Claude, GPT, and Gemini agents. The MCP browser server accepts a connection URL which can point to Browserbase. Standardized protocol for agentic browser tools across providers.

Integration: Configure the MCP server with the Browserbase connection URL. Sessions are created on-demand when the agent invokes a browser tool. Coronium proxy routes through Browserbase session config.

Best for: Claude Desktop agents, cross-provider tool definitions, standardized agent architectures

Puppeteer Extra (Stealth)

89K+ stars (Puppeteer) -- Node.js

puppeteer-extra with the stealth plugin patches automation indicators like navigator.webdriver, window.chrome, and plugin inconsistencies. Works over CDP against Browserbase, stacking Browserbase's built-in stealth with additional patches.

Integration: Use puppeteer-extra.connect({ browserWSEndpoint }) with the Browserbase WebSocket URL. Stealth plugin applies patches to pages created from the CDP connection.

Best for: Existing Puppeteer codebases, targets with aggressive anti-bot detection, legacy agent frameworks

Custom CDP Agents

Protocol-level control -- Any (CDP-capable)

Raw Chrome DevTools Protocol clients (chrome-remote-interface, playwright CDP session) connect directly to Browserbase for low-level control of page events, network interception, and runtime evaluation. Required when existing abstractions are too high-level.

Integration: Connect to the Browserbase WebSocket URL using any CDP library. All network traffic flows through the session-level proxy configured at creation.

Best for: Custom agent runtimes, research projects, specialized fingerprint manipulation, CDP-specific bugs

Browser Use + Browserbase + Coronium (Python)

LLM-driven AI agent that navigates the web through Browserbase with Coronium mobile proxy routing

# pip install browser-use browserbase langchain-openai

import os, asyncio

from browserbase import Browserbase

from browser_use import Agent, Browser

from langchain_openai import ChatOpenAI

bb = Browserbase(api_key=os.environ["BROWSERBASE_API_KEY"])

async def main():

# 1. Create Browserbase session with Coronium proxy

session = bb.sessions.create(

project_id=os.environ["BROWSERBASE_PROJECT_ID"],

proxies=[{

"type": "external",

"server": os.environ["CORONIUM_ENDPOINT"],

"username": os.environ["CORONIUM_USERNAME"],

"password": os.environ["CORONIUM_PASSWORD"],

}],

browser_settings={"stealth": True},

region="us-east-1",

)

# 2. Wire Browserbase CDP URL into Browser Use

browser = Browser(cdp_url=session.connect_url)

# 3. Create LLM-driven agent

agent = Agent(

task="Go to Amazon, search for 'AirPods Pro 3', find the cheapest listing, and return the price and seller name.",

llm=ChatOpenAI(model="gpt-4-turbo"),

browser=browser,

)

# 4. Run agent (routes through Coronium mobile IP)

result = await agent.run()

print("Agent result:", result)

asyncio.run(main())

How it works: Browser Use asks GPT-4 to plan actions step-by-step. Each action (click, type, scroll) executes in Browserbase's managed Chrome via CDP. All network traffic routes through the Coronium mobile proxy. The 90-95% success rate on Amazon (vs ~60% for default Browserbase) comes from the CGNAT-backed mobile IP.

Stagehand + Coronium (TypeScript)

Browserbase's own AI automation SDK with built-in Browserbase session management

// npm install @browserbasehq/stagehand

import { Stagehand } from '@browserbasehq/stagehand';

const stagehand = new Stagehand({

env: 'BROWSERBASE',

apiKey: process.env.BROWSERBASE_API_KEY,

projectId: process.env.BROWSERBASE_PROJECT_ID,

browserbaseSessionCreateParams: {

projectId: process.env.BROWSERBASE_PROJECT_ID,

proxies: [{

type: 'external',

server: process.env.CORONIUM_ENDPOINT,

username: process.env.CORONIUM_USERNAME,

password: process.env.CORONIUM_PASSWORD,

}],

browserSettings: { stealth: true },

});

await stagehand.init();

// LLM-powered actions through Coronium proxy

await stagehand.page.goto('https://linkedin.com');

await stagehand.page.act('click the sign in button');

const profiles = await stagehand.page.extract({

instruction: 'extract the top 5 search results',

schema: z.object({ results: z.array(z.object({ name: z.string(), title: z.string() })) }),

});

Troubleshooting

Common Issues and Fixes

Eight issues you will encounter when integrating Browserbase with Coronium mobile proxies, with specific fixes and debugging approaches for each.

Proxy authentication failure (407 Proxy Authentication Required)

Why it happens: Browserbase attempted to connect through your Coronium proxy but the username/password was rejected. Common causes: typo in credentials, IP whitelist restriction (if enabled), or account quota exhausted.

Fix: Verify credentials in the Coronium dashboard. If IP whitelist is enabled, whitelist the Browserbase egress IP ranges or switch to username/password auth instead. Check account status for quota or payment issues.

DNS leak (browser resolves DNS locally, not through proxy)

Why it happens: By default, some browsers bypass the proxy for DNS resolution, leaking your server's actual DNS queries. The target site may see a mismatch between the proxy IP country and the DNS resolver country.

Fix: Enable "proxy DNS" in Browserbase session config with dnsOverHttps: true, or use SOCKS5h:// scheme instead of socks5:// to force DNS through the proxy. Coronium supports DNS over proxy on all endpoints.

Region mismatch between Browserbase and proxy country

Why it happens: Running a Browserbase US-East session through a German Coronium proxy creates a detectable latency pattern (50-100ms RTT from Virginia to Frankfurt) that differs from real mobile users in Germany.

Fix: Match Browserbase region to proxy country: US proxy + us-east-1/us-west-2 region, EU proxy + eu-west-1 region. For global agents, create parallel sessions per region rather than cross-region routing.

CDP WebSocket disconnects mid-session

Why it happens: Long-running agent loops (10+ minutes) may disconnect due to mobile IP rotation, carrier-level NAT timeout, or network flakiness. Symptoms: "WebSocket is not open" or "Target closed" errors.

Fix: Implement CDP reconnection logic with exponential backoff. Use Browserbase keepAlive: true to preserve session state. Configure Coronium rotation interval higher than your agent's task duration (e.g., 30-minute rotation for 20-minute tasks).

Agent actions fail on Cloudflare Turnstile

Why it happens: Turnstile evaluates browser behavior and IP reputation simultaneously. Browserbase stealth passes the browser check but a flagged proxy IP will still fail. Datacenter proxies and low-quality residential pools trigger Turnstile blocks.

Fix: Use Coronium mobile proxies (CGNAT-backed) for Cloudflare-protected targets. Combine with Browserbase stealth: true. Avoid cycling Cloudflare challenges -- if blocked, rotate the mobile IP rather than retrying immediately.

Inconsistent geolocation data (timezone, locale mismatch)

Why it happens: Browserbase default locale is en-US with UTC timezone. If your Coronium proxy is a German mobile IP, the target site sees a US browser with German IP -- an immediate red flag for fingerprinting systems.

Fix: Set the Browserbase fingerprint.locale and fingerprint.timezone to match the proxy country. German proxy: locale: "de-DE", timezone: "Europe/Berlin". Use Intl.DateTimeFormat().resolvedOptions() to verify in-browser.

LLM agent times out waiting for page load

Why it happens: Mobile proxies add 50-200ms latency per request compared to datacenter. Complex pages may take 5-10 seconds to fully load through a mobile proxy. Default 30-second agent timeouts may fire during legitimate loads.

Fix: Increase page.goto() timeout to 60000ms. Use page.waitForLoadState("domcontentloaded") instead of "load" for faster interaction. Set Browser Use action_timeout to 60 seconds minimum for mobile proxy runs.

Session cost higher than expected

Why it happens: Browserbase charges per session-minute. Long-running agent loops without keepAlive disabled, or sessions that hang on failed actions, accumulate cost without progress. A stuck session running for 30 minutes costs 30 session-minutes.

Fix: Implement hard timeouts at the agent loop level. Use Browserbase session API to terminate stuck sessions programmatically. Set keepAlive: false for one-shot agent runs. Monitor session duration metrics in the dashboard.

Debugging Approach: Session Replay First

When an agent fails, always check the Browserbase session replay first. The dashboard shows exactly what the agent saw: DOM state, network requests, console errors, and video replay. Combined with Coronium's per-device connection logs, you can pinpoint whether a failure originated at the agent reasoning layer (LLM chose wrong action), the browser layer (selector timeout, element missing), or the network layer (proxy auth, DNS leak, 403/429). Don't guess -- the replay tells you.

Pricing Analysis

Pricing Comparison: Browserbase Alone vs Browserbase + Coronium

The cost difference between proxy stacks matters less than the success rate difference. A 60% success rate requires 1.67x more requests to get the same data -- doubling your real cost regardless of headline pricing.

Browserbase Only (Startup tier)

Monthly cost:$39/month + usage

Success rate:60-75%

Strengths: Managed Chrome, built-in stealth, easy setup

Weaknesses: Default Browserbase egress IPs are datacenter origin -- flagged by Cloudflare, DataDome, Akamai. 60-75% success on hard targets.

Best for: Internal tools, non-protected sites, prototyping

Browserbase + Residential Proxy

Monthly cost:$39/month + $50-300/month (GB-based)

Success rate:75-85%

Strengths: Improved IP reputation, real ISP origin

Weaknesses: Per-GB billing unpredictable. Shared residential pools have flagged IPs. Agent tasks that render full pages burn GB quickly.

Best for: Medium-difficulty targets, moderate traffic volume

Browserbase + Coronium Mobile (Recommended)

RECOMMENDED FOR PRODUCTION

Monthly cost:$39/month + from $27/month per Coronium device

Success rate:90-95%

Strengths: CGNAT trust + managed Chrome + unlimited bandwidth. Highest success on protected targets.

Weaknesses: Higher flat cost vs residential for low traffic. Dedicated device model requires capacity planning.

Best for: Production AI agents, LinkedIn, Amazon, Google, booking sites, financial data

Self-Hosted Chrome + Mobile Proxy

Monthly cost:$100-500/month (VPS + Docker + proxy)

Success rate:80-90%

Strengths: Full control, no per-session fees, self-managed fingerprints

Weaknesses: Requires DevOps expertise. Chrome crashes, memory leaks, driver updates, session cleanup all on you. Scaling requires infrastructure work.

Best for: Teams with infrastructure expertise, custom fingerprint requirements, data residency compliance

Effective Monthly Cost for 100K Agent Sessions

Real cost including retries from failed requests on Cloudflare-protected targets

Stack	Base Cost	Success Rate	Retries Needed	Effective Cost
Browserbase Only	$39 + $200 usage	65%	1.54x	$368/mo
Browserbase + Residential (~10GB)	$39 + $200 + $150	80%	1.25x	$486/mo
Browserbase + Coronium (2 devices)cheapest + highest success	$39 + $200 + $54	93%	1.08x	$317/mo

* Assumes 100K sessions/month, 3-minute average session duration, targets including LinkedIn/Amazon/Google. Coronium stack is cheaper AND higher success because mobile proxies eliminate retry overhead.

FAQ

Frequently Asked Questions

Technical answers to common questions about integrating Browserbase with Coronium mobile proxies, AI agent frameworks, session configuration, and production debugging.

Coronium Pricing

Coronium Mobile Proxy Plans for Browserbase

Dedicated 4G/5G mobile proxies with unlimited bandwidth, starting from $27/month per device. Compatible with Browserbase BYOP, Browser Use, Stagehand, and every Playwright/Puppeteer AI agent framework.

Premium Mobile Proxy Pricing

Configure & Buy Mobile Proxies

Select from 10+ countries with real mobile carrier IPs and flexible billing options

📖 Complete Purchase Guide

Choose Billing Period

Select the billing cycle that works best for you

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$129/m

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$97/m

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AT&T • Florida • Monthly Plan

Your price:

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Popular Proxy Locations

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Secure payment methods accepted: Credit Card, PayPal, Bitcoin, and more. 2 free modem replacements per 24h.

Agent Use Cases

AI Agent Applications with Browserbase + Coronium

Production AI agent workloads where the Browserbase + Coronium stack outperforms default browser infrastructure. Each application benefits from CGNAT trust plus managed Chrome.

E-commerce AI Agents

Amazon price monitoring agents with daily run schedules
eBay listing analysis with LLM-driven categorization
Cross-platform price comparison across 20+ marketplaces
Autonomous checkout and inventory agents

Social Media AI Agents

Instagram content analysis and engagement tracking
LinkedIn prospecting agents and profile enrichment
TikTok trend monitoring with autonomous analysis
Cross-platform brand sentiment AI agents

Research & Intelligence Agents

SEO rank tracking with LLM-driven SERP analysis
Brand protection agents for counterfeit detection
Competitive intelligence and market research
Financial data extraction from gated portals

Geographic Agent Coverage

Match Browserbase region to Coronium proxy country for AI agents targeting region-locked content:

Germany France UK Spain Netherlands United States Brazil Poland Australia More EU Countries

Build AI Agents That Actually Work on Protected Targets

Dedicated 4G/5G mobile proxies achieving 90-95% success rates when combined with Browserbase's managed Chrome infrastructure. CGNAT trust + authentic browser fingerprints = production-ready AI agents on LinkedIn, Amazon, Google, and Cloudflare-protected sites.

Compatible with Browserbase BYOP, Browser Use, Stagehand, Playwright, Puppeteer, LangChain, and MCP. HTTP and SOCKS5 support. Unlimited bandwidth with no per-GB billing.

Browserbase BYOP ready

Browser Use compatible

Stagehand supported

MCP server ready

30+ countries

24/7 technical support

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