What does Viewport do?

Viewport focuses on identifying the browser viewport dimensions while resizing a window. It is catalogued under Browser DevTools & extensions on PulseGate.

Viewport is a consumer product built for web developers and designers.

Yes — Viewport is free to use.

What platforms does Viewport run on?

Viewport runs on the web and embeddable surfaces.

Is Viewport still active?

Unverified. Viewport 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 projects are similar to Viewport?

Similar projects tracked by PulseGate include Adjust Viewport Size, Resize Window & Viewport, and Viewport Resizer Plus.

Viewport is developed by Kameron.

When did Viewport launch?

Viewport first shipped in 2017.

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Viewport

Name: Viewport
Author: Kameron

mozilla.orgBrowser DevTools & extensions

Viewport is a Firefox browser extension that shows the current viewport dimensions as the browser window is resized. It helps web developers and designers check responsive layouts and breakpoint sizes during browser-based testing.

FreeWebEmbeddableCloud-managed

Visit mozilla.org

Overview

4 features

Viewport sits in PulseGate's Browser DevTools & extensions category. It focuses on identifying the browser viewport dimensions while resizing a window. Viewport is a consumer product aimed at web developers and designers. Viewport costs nothing to use. It runs on the web and embeddable surfaces.

Behind Viewport is Kameron, and it first shipped in 2017. Among its 4 catalogued features are viewport size display, resize detection, and firefox integration. The interface is available in 32 languages, including Czech, German, and Greek.

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

Viewport size display
Resize detection
Firefox integration
Responsive testing

Built with & integrations

Runs on

BrowserEmbeddableCloud-managed

Trust & compliance

Verified signals

HTTPSPrivacy Policy Terms of ServiceFree tierMulti-languageStore-verified publisher

Legal

Indexing history

What PulseGate has recorded for this listing

Indexed11 Sep · 09:32 UTC
Viewport verified via Firefox Add-ons
Source: Firefox Add-ons · Open

Frequently asked questions about Viewport

What does Viewport do?: Viewport focuses on identifying the browser viewport dimensions while resizing a window. It is catalogued under Browser DevTools & extensions on PulseGate.
Who is Viewport for?: Viewport is a consumer product built for web developers and designers.
Is Viewport free?: Yes — Viewport is free to use.
What platforms does Viewport run on?: Viewport runs on the web and embeddable surfaces.
Is Viewport still active?: Unverified. Viewport 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 projects are similar to Viewport?: Similar projects tracked by PulseGate include Adjust Viewport Size, Resize Window & Viewport, and Viewport Resizer Plus.Adjust Viewport Size Resize Window & Viewport Viewport Resizer Plus
Who makes Viewport?: Viewport is developed by Kameron.
When did Viewport launch?: Viewport first shipped in 2017.

At a glance

Pricing: Free
Platforms: Web
First seen: 11 Sept 2026
Built for: web developers and designers
Model: B2C
Solves: Identifying the browser viewport dimensions while resizing a window.

Registered as

Firefox Add-ons: viewport

Developer

Kameron

Index record

Indexed: 11 Sep 2026
Lifecycle: Alive
First seen: Sep 2026
Last seen: 11 Sep 2026

Identity audit (13)

Slug: viewport-mozilla-org
Lifecycle state recorded: 11 Sept 2026
Verification state: Indexed for public listing
Listing state: Listed: yes
Index status: Included in index
Latest evidence snapshot: 11 Sept 2026
Timeline basis: Indexed-at chronology (no inferred launch/funding milestones).
Name from: Derived from the project's own page and URL.
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: 11 Sept 2026
Canonical URL: https://addons.mozilla.org/en-US/firefox/addon/viewport

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