What Is My Browser

Introduction:

Every web request includes a User-Agent string that quietly advertises the visitor’s browser, operating-system, rendering engine and sometimes device model. Developers rely on this identifier to diagnose compatibility issues, deliver polyfills and gather analytics, yet modern strings are long, irregular, and often obfuscated.

This tool parses the raw string entirely in your browser, extracts meaningful tokens, and merges them with live properties such as platform, language and screen resolution. You can copy the results as CSV or JSON, or download them for incident reports and regression testing.

Paste the fragment into a diagnostics dashboard or share the exported file with QA to reproduce edge-case bugs on the exact client profile — remember that spoofed headers may produce misleading output.

Technical Details:

Foundational Principles

User-Agent strings follow no universal grammar; vendors append version tokens, platform hints and localization codes in varying orders. A parsing library tokenises the string, then applies heuristic maps maintained by its community to infer browser family, major version, rendering engine and operating-system lineage. The tool freezes the result object to guarantee immutability and prevent accidental mutation during reactive updates.

Supplementary properties, such as navigator.platform and window.screen, come directly from the runtime environment, ensuring that spoofed or truncated strings still yield useful diagnostics.

Formula Overview

Variables & Parameters

Scoring & Categorisation

• Desktop – no device.type token or explicit “desktop”.
• Mobile – type equals “mobile” or “tablet”.
• Legacy browser – major version < 60 for Chromium-based or < 80 for Gecko-based engines.
• High-density screen – width ≥ 1920 px and device-pixel-ratio ≥ 2.

Representative Calculations

Edge Cases & Assumptions

• Empty navigator.userAgent returns “Unknown” fields handled.
• Custom user-agents longer than 512 chars are truncated for display.
• Out-of-order version tokens may misclassify minor releases.
• Embedded browsers (e.g., in messaging apps) inherit host engine data.

Performance & Stability

The parsing step runs in O(n) with n equal to the header length. Numeric precision is irrelevant, but string allocations are capped by freezing the result object. All processing is client-side, so no network latency or privacy risk is introduced.

Step-by-Step Guide:

Follow this quick sequence to harvest a complete browser fingerprint for debugging or support tickets.

1. Load the page; the Info tab auto-populates.
2. Review key fields such as Browser, Engine and Operating System.
3. Click Copy CSV to place a spreadsheet-ready table on your clipboard.
4. Switch to JSON for the raw structured output, then choose Download JSON if you need an attachment.
5. Always confirm that the reported string matches expectations on devices with custom security software.

FAQ:

Glossary:

User-Agent

Header string identifying the client software.

Rendering Engine

Core component that interprets HTML, CSS and scripts.

Immutability

State that cannot be altered after creation.

Heuristic

Problem-solving technique based on practical discovery.

Polyfill

Code that back-ports missing browser features.