Sec-CH-UA-Model

The HTTP Sec-CH-UA-Model request header provides the device model name for mobile devices on which the browser is running.

Baseline: Limited availability

Supported in Chromium-based browsers (Chrome, Edge, Opera). webstatus.dev

Table of Contents

Usage

The Sec-CH-UA-Model header is part of the User-Agent Client Hints infrastructure. Mobile browsers send this hint to inform servers about the specific device model. Servers use the model name to tailor content, apply device-specific optimizations, or log analytics about which hardware models access a service.

This header is a high-entropy hint. Browsers only send high-entropy hints after the server explicitly requests them via Accept-CH. The default behavior omits this header to preserve privacy. Servers needing device model information must opt in by listing Sec-CH-UA-Model in the Accept-CH response header.

Since Chrome's User-Agent reduction, the mobile UA string freezes the device model to the literal K token. Server-side code previously parsing the model from the User-Agent string must now request Sec-CH-UA-Model through Accept-CH to receive actual device information.

Mobile web applications commonly request Sec-CH-UA-Model to detect devices with known hardware limitations or capabilities. A streaming video service receiving "Pixel 7" knows the device supports modern codecs and high-resolution playback. A mapping application receiving "SM-S918B" (Samsung Galaxy S23 Ultra) knows the device has GPS and a high-density display.

Desktop browsers typically send an empty string for this header. Desktop computers do not have standardized model names the way mobile devices do. The header becomes meaningful only on phones and tablets.

The header is sent only over secure connections (HTTPS). The value is a quoted string matching the device marketing name or internal model identifier.

Values

Device model string

The value is a quoted string containing the device model name. Common formats include marketing names like "Pixel 7", "SM-S911B", or internal model codes like "SM-S918B" (Samsung), "CPH2451" (OnePlus). Desktop browsers send an empty string "".

Example

A mobile site requests device model information to optimize image delivery. The server sends Accept-CH requesting model details. A phone running Chrome responds with its model name. The server uses this to determine screen resolution and memory constraints.

Sec-CH-UA-Model: "Pixel 7"

A streaming service checks the device model to select video quality presets. A mid-range Android phone reports its model code. The service applies bitrate limits appropriate for the device's video decoding capabilities.

Sec-CH-UA-Model: "SM-S918B"

A desktop browser responds with an empty model string. The server interprets this as a non-mobile platform and serves the full desktop experience without device-specific adaptations.

Sec-CH-UA-Model: ""

Takeaway

The Sec-CH-UA-Model header tells the server the specific mobile device model running the browser, enabling servers to optimize content and features based on known hardware capabilities.

See also

Last updated: March 6, 2026