Google Lens Modes

lns_mode is a parameter that classifies Google Lens queries into text, un (unimodal), or mu (multimodal).

Google Lens has quietly become one of the most advanced visual search tools in the world. Behind the scenes, it works by constructing detailed, context-rich search queries that include a growing set of parameters. One of the newest additions to this query structure is lns_mode, introduced on May 14, 2024 by Google engineer Jason Hu.

This article breaks down what lns_mode is, how it fits into the broader Google Lens ecosystem, and why it matters – especially as Lens evolves into a key component of Google’s new AI Mode.

What Is lns_mode?

The lns_mode parameter is a query string field appended to URLs generated during Lens-powered searches. It serves as a high-level indicator of the type of search being executed. Based on Chromium source files, the known values are:

• text – text-only search (e.g., OCR text selection)
• un – unimodal image-only search
• mu – multimodal search (text + image)

This field complements others like q (query), gsc=1, masfc=c, and hl (locale).

Why Was lns_mode Added?

Two key reasons:

1. Routing: Lens requests are increasingly complex. The backend must differentiate between modes to deliver the right results and UI.
2. AI Mode support: In April 2025, Google announced that Lens multimodal queries were integrated into AI Mode using Gemini. lns_mode=mu enables this functionality.

Read the official blog post about AI Mode

Example URLs

https://www.google.com/search?q=apples&lns_mode=text&gsc=1&masfc=c&hl=en-US

https://www.google.com/search?q=&lns_mode=un&gsc=1&masfc=c&hl=en-US

https://www.google.com/search?q=green+apples&lns_mode=mu&gsc=1&masfc=c&hl=en-US&vsrid=...

How Is It Used?

Inside Chromium, lns_mode is added in the Lens Overlay URL builder logic. Functions like BuildTextOnlySearchURL() and BuildLensSearchURL() select the mode dynamically based on the presence of OCR text, screenshots, or user-selected regions.

Search Parameters

Below is a breakdown of the most common query parameters used in Google Lens search URLs:

Parameter	Description	Example Value
q	The text search query (OCR result, user input, etc.).	green+apples
lns_mode	Specifies the Lens mode: text = text-only un = unimodal (image-only) mu = multimodal (image + text)	text
gsc	Marks the request as a Lens Search Companion query.	1
masfc	Indicates the query came from an ambient (contextual) source.	c
hl	User language/locale.	en-US
mactx	Encoded metadata about the current page (title and URL), serialized as a Base64URL string.	Base64-encoded context
gsessionid	Session identifier for grouping multiple queries.	1234567890abcdef
vsrid	Encoded request ID identifying the Lens request; includes UUID and sequence data.	Base64-encoded ID
udm	UI mode flag used internally by Google: 26 = unimodal 24 = multimodal	24

These parameters are assembled automatically by Chrome and Lens-backed apps when performing visual search, with each field enabling a richer, more context-aware response from Google’s backend systems.