---
title: "Custom User Agent (UA) Strings"
slug: "custom-user-agent-ua-strings"
updated: 2025-12-02T16:42:39Z
published: 2025-12-02T16:42:39Z
canonical: "help.silentpush.com/custom-user-agent-ua-strings"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.silentpush.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom User Agent (UA) Strings

You can emulate specific viewer behaviors by automatically generating a User-Agent (UA) string based on your Platform, OS, and Browser selections. The UA tells the target site “who” is visiting (e.g., a Chrome user on Windows), which can reveal conditional content, such as mobile redirects or region-locked threats.

For full control, use the **Custom** option in User Agent Parameters. This overrides defaults with your own string, ideal for testing legacy browsers, bots, or evasion scenarios.

![](https://cdn.document360.io/8e5460b3-9d96-4b01-8bb3-6591a4af3a8c/Images/Documentation/Screenshot%202025-11-13%20at%201.26.20%E2%80%AFPM.png)

1. In **Advanced Scan**, enter your URL (e.g., [https://silentpush.com)](https://silentpush.com))
2. Set **Region** (e.g., North America, uses residential proxy for realism).
3. Under **User Agent Parameters**:
  - Select Platform (e.g., Desktop) or click **Custom**.
  - In User Agent, enter a string (e.g., for mobile testing) and click **Scan**.

### UA Structure Basics

A good UA starts with Mozilla/5.0 (compatibility flag), followed by platform/OS details, then browser specifics. Keep it realistic to avoid detection; invalid syntax (e.g., mismatched versions) may trigger bot blocks or errors.

#### Example UAs

| Category | Device/OS/Browser | Example UA String |
| --- | --- | --- |
| **Desktop** | Windows/Chrome 139 | Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36 |
| **Desktop** | macOS/Firefox 131 | Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:131.0) Gecko/20100101 Firefox/131.0 |
| **Desktop** | Windows/Edge 142 | Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36 Edg/142.0.0.0 |
| **Desktop** | macOS/Safari 18 | Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Safari/605.1.15 |
| **Mobile** | Android/Chrome 139 | Mozilla/5.0 (Linux; Android 10; SM-G975F) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Mobile Safari/537.36 |
| **Mobile** | iOS/Safari 18 | Mozilla/5.0 (iPhone; CPU iPhone OS 18_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0 Mobile/15E148 Safari/604.1 |
| **Other** | Linux/Crawler Bot | Mozilla/5.0 (compatible; SilentPushBot/1.0; +https://silentpush.com/bot) |

> Advanced scans reflect the selected parameters, allowing you to see how a URL appears under different conditions. For guidance on analyzing scan results, see [Work with Live Scan Data](https://help.silentpush.com/docs/working-with-live-scan-data).