What is a User-Agent string?
An HTTP User-Agent string is a request header sent by web browsers, mobile apps, and automated crawlers to web servers. It communicates the client's software application, operating system version, rendering engine (Blink, WebKit, Gecko), and device type.
Because user-agent strings contain complex historical compatibility tokens (e.g. Mozilla/5.0 and like Gecko), EasyExtract normalizes these strings into clean structured attributes.
How to parse User-Agent strings and extract device information
- Paste User-Agent headers. Paste one or hundreds of User-Agent strings into the text box, or click 'Use My Current User-Agent'.
- Click Parse User-Agents. The local parser evaluates regular expression signatures to identify browsers, operating systems, engines, and bots.
- Inspect structured device metrics. Review the decoded properties including browser version, OS release, device form-factor, and crawler status.
- Download CSV or JSON. Export the parsed dataset as a clean CSV table for log auditing or a JSON array for analytics ingestion.
What attributes are extracted?
- Browser Name & Version — Chrome, Safari, Firefox, Edge, Opera, Samsung Internet.
- Operating System — Windows (10/11/7), macOS, iOS, iPadOS, Android, Linux, ChromeOS.
- Device Form Factor — Desktop, Mobile, Tablet, Smart TV, Bot / Crawler.
- Rendering Engine — Blink, WebKit, Gecko, Trident.
- Search Engine & AI Bots — Googlebot, Bingbot, GPTBot, ClaudeBot, PerplexityBot, AhrefsBot.
Supported formats
Supports all RFC 7231 / RFC 9110 compliant User-Agent headers from desktop browsers, mobile devices, HTTP clients (cURL, Python Requests), and search engine spiders.
Privacy and log security
Processing happens entirely inside your browser tab. Sensitive internal access logs, user session IDs, and enterprise telemetry never leave your machine.
Known limitations
Client hints (Sec-CH-UA) are increasingly used by modern browsers to reduce fingerprinting; the tool extracts data from the standard User-Agent header string provided.
Common use cases
- Access Log Auditing — Parsing Nginx or Apache access logs to determine visitor device distributions.
- Bot & Scraper Detection — Identifying AI scrapers and search engine spiders accessing your web servers.
- Cross-Browser QA Testing — Verifying user-agent strings sent by automated Selenium or Cypress test suites.
User-Agent Parser vs Log Field Extractor
Use the User-Agent Parser when you want deep device and browser classification for UA strings. If you need to extract IP addresses, HTTP status codes, or timestamps from raw log lines, use our log field extractor.
Frequently asked questions
What does a User-Agent string tell you?
It tells you what browser, browser version, operating system, and rendering engine the visitor used, or whether the visitor was an automated search bot.
How do I detect bots and AI crawlers in User-Agent logs?
EasyExtract automatically matches signatures for Googlebot, Bingbot, GPTBot, ClaudeBot, and over a dozen other major crawlers.
Can I parse thousands of User-Agent strings at once?
Yes. Paste a list of up to 50,000 User-Agent strings and download the structured result as a CSV spreadsheet.
Why does my User-Agent say Mozilla/5.0 even when using Chrome?
Almost all modern browsers include 'Mozilla/5.0' for legacy compatibility with historical web servers.
Are my visitor logs uploaded to any server?
No. All parsing runs locally in your browser memory using JavaScript — nothing is ever transmitted across the network.