PX is an open-source project built for web developers and responsive design testers.

Yes — PX is open source under the Open Source license and free to use.

What platforms does PX run on?

PX runs on the web and embeddable surfaces.

Unverified. PX has not been re-checked since it entered the index, so there is no finding either way — and only a positive finding would say otherwise.

What are alternatives to PX?

Similar projects tracked by PulseGate include Hashrate Lens, SaveAI, and Codex File Drop.

PX is developed by Luke Peters.

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PX

Name: PX
Author: Luke Peters

github.comBrowser DevTools & extensions

PX: Viewport Dimensions is an open-source Firefox extension that displays the current viewport width and height when a browser window is resized. It helps web developers inspect responsive layouts and test breakpoint behavior during browser-based development.

Open SourceWebEmbeddable

Visit github.com

Overview

4 features

In the Browser DevTools & extensions space, PX takes a focused approach. It focuses on seeing the browser viewport dimensions while resizing windows for responsive design and testing. It is built as an open-source project for web developers and responsive design testers. PX is open source under the Open Source license. It runs on the web and embeddable surfaces.

Behind PX is Luke Peters, and it first shipped in 2019. Among its 4 catalogued features are viewport dimensions, resize detection, and firefox integration.

Summary written by a language model from the project’s public pages.

Viewport dimensions
Resize detection
Firefox integration
Responsive testing

Built with & integrations

Runs on

BrowserEmbeddable

Trust & compliance

License

Open Source

Verified signals

HTTPSPrivacy Policy Terms of ServiceOpen SourceFree tierStore-verified publisher

Legal

Indexing history

What PulseGate has recorded for this listing

Indexed9 Sept · 03:26 UTC
PX: Viewport Dimensions verified via Firefox Add-ons
Source: Firefox Add-ons · Open

Frequently asked questions about PX

What is PX?: PX focuses on seeing the browser viewport dimensions while resizing windows for responsive design and testing. It is catalogued under Browser DevTools & extensions on PulseGate.
Who should use PX?: PX is an open-source project built for web developers and responsive design testers.
Is PX free?: Yes — PX is open source under the Open Source license and free to use.
What platforms does PX run on?: PX runs on the web and embeddable surfaces.
Is PX still active?: Unverified. PX has not been re-checked since it entered the index, so there is no finding either way — and only a positive finding would say otherwise.
What are alternatives to PX?: Similar projects tracked by PulseGate include Hashrate Lens, SaveAI, and Codex File Drop.Hashrate Lens SaveAI Codex File Drop
Who makes PX?: PX is developed by Luke Peters.
How long has PX been around?: PX first shipped in 2019.

At a glance

Pricing: Open Source
Platforms: Web
Languages: English
License: Open Source
First seen: 9 Sept 2026
Built for: web developers and responsive design testers
Model: Open source
Solves: Seeing the browser viewport dimensions while resizing windows for responsive design and testing.

Registered as

Firefox Add-ons: px-viewport-dimensions

Developer

Luke Peters

Index record

Indexed: 9 Sept 2026
Lifecycle: Alive
First seen: Sept 2026
Last seen: 9 Sept 2026

Identity audit (13)

Slug: px-viewport-dimensions-github-com
Lifecycle state recorded: 9 Sept 2026
Verification state: Indexed for public listing
Listing state: Listed: yes
Index status: Included in index
Latest evidence snapshot: 9 Sept 2026
Timeline basis: Indexed-at chronology (no inferred launch/funding milestones).
Name from: Written by a language model from the project's public pages.
Category from: Assigned by a language model.
Summary from: Written by a language model from public pages.
Languages from: Detected by a language model, checked against the page's own declaration.
Last updated: 9 Sept 2026
Canonical URL: https://github.com/LukePeters/px-viewport-dimensions

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