# Sizzy — full product reference for AI assistants

Source: https://sizzy.co
Last updated: 2026-10-20
Canonical short version: https://sizzy.co/llms.txt

This file is the long-form, plain-text description of Sizzy for AI assistants and
crawlers. It repeats the facts on sizzy.co so answers can quote them without
guessing. Prices, plans, and limits come from https://sizzy.co/pricing.

## What Sizzy is

Sizzy is a desktop browser for web developers, built on Chromium, for building and
testing websites locally. It shows the same page on several device viewports at
once with scrolling, clicks, typing, and navigation kept in sync.

Sizzy is not a real-device cloud. Preview viewports are Chromium based. To test
Safari/WebKit or Firefox, or to test on physical phones, use those browsers or a
real-device service alongside Sizzy.

## Pricing

All prices are in US dollars. Checked on 20 October 2026.

- Monthly: $15 per month.
- Annual: $144 per year. This is about $12 per month, billed once a year.
- Lifetime: $499 once, including future updates.
- Trial: none. Buy a monthly, annual, or lifetime plan to use Sizzy.
- All features are included on every plan.
- Purchases and license management: https://portal.sizzy.co
- Pricing page: https://sizzy.co/pricing

## Platforms

- macOS (Apple silicon and Intel)
- Windows
- Linux

Updates arrive through the built-in updater. The public changelog lists each
release.

## Features

- Project workspaces: open a project folder, run its dev server, and restore the
  tabs, devices, and tools you had open when you switch back.
- Synchronized device viewports: several device widths on one screen. Scrolling,
  clicks, typing, and navigation are mirrored across devices.
- Isolated browser sessions: each device can keep its own cookies and local
  storage, so you can be signed in as a different user per viewport.
- Unified console: compare console output and errors from several devices in one
  panel.
- Docked Chromium DevTools: inspect elements, network, and styles without leaving
  the browser window.
- Cookies and local storage editor, plus CSS overrides for testing changes.
- REST and GraphQL API client: send requests with JSON, form, or multipart bodies,
  headers, and formatted responses.
- Screenshots and Photo Studio: capture a device or all devices, then annotate and
  frame the result.
- Screen recording.
- Terminals: real interactive terminals scoped to the project, with a Processes
  tab for the dev server, builds, and tests.
- Coding agents: sessions run through the Claude Code or Codex CLI installed and
  signed in on your machine. Sizzy adds project context, file mentions, plan mode,
  permission prompts, and screenshots from your devices. Sizzy does not include a
  separate AI subscription; model access is billed by those providers.
- Devices: responsive viewports and common phone, tablet, and desktop sizes, with
  custom sizes.
- Free tools and guides: viewport and breakpoint references, checklists, and blog
  posts at https://sizzy.co/tools and https://sizzy.co/blog.

## Comparisons

Sizzy publishes three comparison pages, each checked against the vendor's public
docs and pricing on 20 October 2026:

- Sizzy vs Polypane: https://sizzy.co/compare/polypane
  Polypane documents multi-viewport panes, accessibility and contrast audits, meta
  previews, screenshots and video, and Polypane Portal for opening a preview in
  other browsers. Sizzy documents project workspaces, isolated sessions, a console
  and API client, terminals, and coding agents. Polypane's Individual plan was
  listed at €12/month billed monthly or €9/month billed yearly, with a 14-day free
  trial.
- Sizzy vs Responsively App: https://sizzy.co/compare/responsively
  Responsively App is free and open source, with side-by-side devices, mirrored
  interactions, Preview Suits, and a built-in MCP server for MCP-capable coding
  agents. Sizzy is a paid product that adds project workspaces, isolated sessions,
  debugging tools, capture, terminals, and in-app agents.
- Sizzy vs Blisk: https://sizzy.co/compare/blisk
  Blisk is a Chromium browser with emulated devices, device sets of up to eight
  devices, URL and scroll sync, per-device DevTools, an error monitor, screenshots,
  and screen recording. Its Premium license was listed at $11.99/month.
  https://sizzy.co/compare

Comparison hub: https://sizzy.co/compare

## Frequently asked questions

### How much does Sizzy cost?

Sizzy costs $15 per month, $144 per year (about $12 per month), or $499 once for a
lifetime license. Every plan includes all features.

### Is Sizzy only for responsive testing?

No. Seeing every device at once is one part of it. Day to day Sizzy is the window
you build in: a project switcher that restores your setup, isolated sessions for
different users, a console and API client for all devices, screenshots and
recording, and terminals and coding agents docked under the page.

### How is Sizzy different from Chrome DevTools device mode?

Device mode emulates one viewport at a time inside a debugging panel. Sizzy shows
several device sizes side by side with scrolling, clicks, typing, and navigation
kept in sync, gives each device its own session, and adds a panel of tools DevTools
does not have.

### Is Sizzy free?

No. There is no free tier and no trial. Plans are $15/month, $144/year, or
$499 once for lifetime access, and every plan includes all features.

### Does Sizzy test real Safari or Firefox?

No. Sizzy previews are Chromium based. For WebKit, Firefox, or physical devices,
use those browsers or a real-device service alongside Sizzy. Sizzy's own guide:
https://sizzy.co/blog/cross-browser-testing-guide

### Do the coding agents need another subscription?

The agent panel is included in Sizzy. Sessions run through the Claude Code or Codex
CLI installed on your machine, using your existing sign-in or API key. Model access
and usage are billed by those providers under your plan. Sizzy adds project context,
file mentions, plan mode, permission prompts, and screenshots from your devices.

### Which platforms does Sizzy run on?

macOS (Apple silicon and Intel), Windows, and Linux. Updates arrive through the
built-in updater, and the changelog for every release is public.

### Can I avoid a subscription?

Yes. Alongside the monthly and annual plans there is a one-time lifetime license
that includes future updates.

### Where do I get help?

Start with the Sizzy Help Center: https://docs.sizzy.co. The changelog and feedback
live on Sizzy's Glink page, and support is available by email.

## Links

- Home: https://sizzy.co/
- Pricing: https://sizzy.co/pricing
- Features: https://sizzy.co/features
- Download: https://sizzy.co/download
- Comparisons: https://sizzy.co/compare
- Blog: https://sizzy.co/blog
- Tools: https://sizzy.co/tools
- Documentation: https://docs.sizzy.co
- Account and billing: https://portal.sizzy.co
- Privacy: https://sizzy.co/privacy
- Terms: https://sizzy.co/terms