Browser3

A multi-profile antidetect Chromium browser for people and AI agents.

Create isolated browser profiles with persistent, internally consistent identities — designed for manual use, automation and long-running AI agents.

Persistent, internally consistent browser identities.

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One profile = one persistent browser identity.

For agent workflows: one agent = one persistent browser identity.

Each saved profile combines a deterministic identity configuration with its own Chromium user-data directory. Selecting that profile again reuses both; native Chromium code consumes the identity configuration without injected page scripts.

Why Browser3?

Benefit	What it means in Browser3
Persistent identities	A saved profile reuses its seed, generated configuration and Chromium user-data directory.
Multi-profile isolation	Each profile has separate cookies, history, storage, preferences and identity data.
Native Chromium integration	Fingerprint handling lives inside the packaged browser, not in injected JavaScript or CDP injection.
Internally consistent browser identities	Profile generation uses host measurements and coherence rules across UA/UA-CH, hardware buckets, display, locale, time zone and GPU/WebGL data.
Human + AI workflows	Profiles run as normal headful sessions. Scriptable profile selection and supported Playwright / CDP automation are available via opt-in controls.
Local-first architecture	Browser3-managed profiles, browsing data, measurements, caches, state and logs stay local. Browser3 adds no vendor telemetry.

Demo

The local TASK-005 v4 demo combines two separate owner-supplied Fingerprint signal views, the captured Pixelscan observation and a five-profile lifecycle card. The GIF is the compact preview; the MP4 is the full-quality version.

Open the MP4 v4 demo · Fingerprint reference 1 · Fingerprint reference 2

The Fingerprint section shows two owner-supplied sanitized screenshots as separate full-frame views using contain scaling. Concrete IP, geolocation, visitor, request and event identifiers are not visible. The owner-approved velocity row shows only the aggregate text “1 IP, 1 Linked ID in the past 24 hours”, not a concrete IP or Linked ID. The five-slot montage intentionally repeats one full-frame visual reference; it is not five independent fresh measurements. The measured five-profile lifecycle and external-service scope remain in the dated PUBLIC_VALIDATION.md.

Quick start

Download Browser3-<version>-windows-x64.zip from the latest official release. GitHub's automatically generated Source code (zip) and Source code (tar.gz) archives are not Browser3 installers. The signed public-source snapshot is Browser3-public-source-<version>.zip.

Extract the complete archive, keep runtime\ intact, open PowerShell or Command Prompt in the extracted directory, and run:

.\browser3

or using Python directly:

python launcher.py

On first run, Browser3 automatically measures host characteristics (once, about 15 seconds), generates default profiles, and starts the browser session.

To reopen profile 1 and return to the same saved identity:

.\browser3 --profile 1

Useful existing commands:

# Use the host network even when proxy.txt contains entries
.\browser3 --profile 1 --no-proxy

# Inspect the launch command without starting Chromium
.\browser3 --profile 1 --dry-run

# List all implemented options
.\browser3 --help

AI agents and automation

The launcher provides scriptable profile selection, profile locking, optional sticky proxy assignment and headful Chromium launch. It also supports opt-in CDP automation (via --control cdp or the local Session API) for Playwright, Puppeteer and AI agents, while default launches keep CDP disabled so normal sessions stay completely CDP-free.

See the CLI & automation reference for implemented controls and their current status.

Benchmarks

A sanitized five-profile validation report is included in this source layer. On Browser3 149.0.7827.201 it recorded selected same-profile signals as stable in 15/15 reload comparisons, 5/5 close/reopen comparisons and 5/5 new browser-process comparisons. The private isolation comparison found 5/5 distinct profile signatures in each lifecycle phase.

Fingerprint.com tampering-model averages ranged from 0.0283 to 0.0335 across the three five-profile phases, compared with the historical per-machine average of 0.1053. The virtual-machine model ranged from 0.0580 to 0.0600, compared with 0.0466 historically. VPN is not part of the required release gate. These are observations from one host and network context, not guarantees of future detector results or anti-bot bypasses.

See the public validation report for the method, native reference, external cross-checks, screenshot and known limitations. In particular, the recorded GPU combinations do not support a public host-coherence claim. Browser3 does not claim to be “undetectable”.

How it works

1. Public source — MPL-2.0 Python orchestration, host probing, profile-generation policy, proxy helpers, GPU catalog and release documentation.
2. Private native layer — the fingerprint engine and Chromium integration patches, distributed in object form under the binary license. The public snapshot cannot build the executable.
3. Profile data — seeded JSON configurations and separate Chromium user-data directories below %LOCALAPPDATA%\Browser3.
4. Chromium runtime — the patched runtime below runtime\; the launcher supplies the chosen configuration and user-data directory, and native code applies available values.

Python handles orchestration and policy; fingerprint handling remains inside Chromium. See Public and private boundary for the exact split.

Requirements and limitations

Component	Requirement
Operating system	Windows 10 version 1809 (build 17763) or newer, x64
Python	Python 3.7 or newer, available as python in PATH
Graphics	A physical GPU with working hardware acceleration
Display scaling	Any Windows scaling level; 125% and 150% are supported

• No installer or standalone Browser3 CLI is claimed today.
• Profiles are generated for the current machine. Moving them to different hardware is unsupported because hardware claims may no longer match.
• Browser3 PE files are not Authenticode-signed. Verify the signed checksum manifest; do not disable SmartScreen or antivirus protection.
• Widevine is not included. DRM-protected streaming services may not work, and Windows N/KN may require the Microsoft Media Feature Pack for H.264/AAC playback.
• The current release gate was completed without a proxy. Proxy and multi-geo operation were not part of that release's tested GO.
• Proxy geolocation, when used, calls the free unencrypted ip-api.com HTTP endpoint through the configured proxy.
• The demo is a visual supplement; validation is limited to the scope documented in PUBLIC_VALIDATION.md.
• Fingerprint and network-risk results depend on the host, proxy/IP reputation and changing detector behavior. Browser3 does not guarantee bypasses or scores.

Documentation

• CLI & automation reference
• Frequently asked questions
• Release notes
• Public and private boundary
• Privacy
• Support
• Security policy
• Contributing
• Acceptable Use Policy

Use Browser3 only on systems and accounts you own or are authorized to test. Use GitHub Issues for reproducible bugs or feedback; report vulnerabilities through SECURITY.md.