Responsively App vs Sizzy (2026): which should you pick?
As of Nov 13, 2026, Responsively App grades higher than Sizzy: 3.0 against 1.6 out of 4.0.
Checked Nov 13, 2026 · graded Nov 13, 2026 by ToolGPA
Responsively App grades higher on value for money, the free plan and ease of use. They get the same grade on features and platforms.
Price, platforms and features side by side. The table says where each price was read and when.
Responsively App
Free open source browser that shows many device sizes at once
Which one is for you
Pick Responsively App if
- Fits if you build responsive sites and want to check many screens at once
- Works for front-end developers who want a free tool, not a subscription
Look elsewhere if
- Not for you if you want a daily browser, as it is a developer tool
- Skip it if you need Safari or Firefox engines, because it previews with Chromium
- Watch out: it runs on Mac, Windows and Linux only, with no mobile version
- Too light for debugging, as it has no extra tools listed beyond an inspector and screenshots
Pick Sizzy if
- Fits if you are a front-end developer who wants every device in one workspace
- Works for developers who run coding agents next to the preview
Look elsewhere if
- Skip it if you want to try before paying, as there is no free plan and no trial
- Pricey if you want a free option, as free tools like Responsively cover device previews
- Watch out: coding agents run through your own Claude Code or Codex CLI, billed by those providers
- Not for you if you want a phone app, as it is desktop only
How we grade them
| 3.0GPAResponsively AppVery good | 1.6GPASizzyWeak | |
|---|---|---|
| Value for money | AFree and open source, with no paid plans listed. | C$12 a month billed yearly, between the category's $10 middle and $19.99 dearer quarter. Lifetime is $499, over two years of a typical $10 a month. |
| Free plan and trial | AThe whole app is free, with no paid plans listed on its site or GitHub page. | FNo free plan and no free trial on the pricing page. |
| Features | CMany device views, mirrored interactions, device profiles and screenshots. It does that job fully, but it is a smaller job than a full developer toolset. | CDevices on one canvas, project workspaces, isolated sessions, a debug panel, screenshots and terminals. It is a developer tool, and the coding agents need separate CLIs. |
| Ease of use | BNo store rating on record. Install it, enter a URL and see the devices. | CNo store rating on record, and projects, sessions and agent CLIs take setting up. |
| Platforms and integrations | CDesktop only: macOS, Windows and Linux. No mobile app and no integrations listed. | CDesktop only: macOS, Windows and Linux, linking GitHub, Vercel, Coolify, Claude Code and Codex. |
| Best for | previewing a site on many screen sizes at once | a developer browser with synced device previews |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: Responsively App and Sizzy. How we grade
Price against what you get
Responsively App has no paid plan and scores 2.3 out of 4 on features, ease of use and platforms. Sizzy starts at $12 a month and scores 2.0.
Responsively App scores higher and starts $12 a month lower. Of the other browsers on the chart, none scores higher than Responsively App for less, and 31 score higher than Sizzy for less.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
Where they differ
- Responsively App is open source, according to its own site.
- Sizzy can be bought with a one-time purchase.
- Sizzy also covers screen recording.
At a glance
| Responsively App | Sizzy | |
|---|---|---|
| Pricing | Free | Paid |
| Starts at | Free | $12 per month, billed annually ($15 billed monthly) |
| Free plan | The whole app is free; its site and GitHub page list no paid plans. | None |
| Free trial | None listed | None listed |
| macOS | ||
| Windows | ||
| Linux | ||
| Made by | Responsively App | Kitze |
| Price read from | responsively.app | sizzy.co |
| Checked | Nov 13, 2026 | Nov 13, 2026 |
Worth knowing
Responsively App
- It is a developer tool, not a general-purpose daily browser.
- It is built on Electron, so it previews sites with Chromium rather than Safari or Firefox engines.
- It runs on Mac, Windows and Linux only, with no mobile version.
- A beta channel is offered next to the stable release.
Sizzy
- There is no free plan and no free trial on the pricing page.
- Coding agents run through the Claude Code or Codex CLI you install, and those providers bill model usage under your own plan.
- It is a desktop developer tool for macOS, Windows and Linux, with no mobile version.
- Checkout and licenses are handled on a separate portal site, and the page says regional pricing is shown at checkout.
Key features
Responsively App
- All devices at once
- Many device previews show side by side, so there is no need to resize the dev tools window.
- Mirrored interactions
- A click, scroll or navigation in one preview is repeated in all the others in real time.
- Preview Suites
- Favorite device combinations are saved as Preview Suites and switched between while testing.
- Device profiles
- A large collection of device profiles is built in, and custom devices can be added.
- Unified Inspector and screenshots
- One inspector covers every device, and full-page screenshots of all devices are taken in one click.
- Ordinary browser features
- Cookie, local storage and session storage management, bookmarks and the usual dev tools are included.
Sizzy
- Devices on one canvas
- Real device sizes and user agents sit side by side, and scrolling, clicks, typing and navigation stay in sync until sync is switched off.
- Project workspaces
- Each project keeps its URLs, devices, sessions, notes, snippets and terminals, plus its repo path, dev command and editor.
- Isolated sessions
- Cookies, cache and storage are kept separate per session, so you can test as an admin, a customer and a guest at once.
- Debugging panel
- One console for all devices, docked Chromium DevTools, storage and CSS editors, request headers and an API client.
- Screenshots and Photo Studio
- Capture one device or all of them, full page or framed, and record video or GIF of the canvas.
- Terminals and coding agents
- Run dev commands and hand tasks to the Claude Code or Codex CLI already on your machine.
Plans
Responsively App
Free$0
The full app, free and open source. The project takes sponsorships but sells no plans.
Sizzy
Monthly$15
per month, billed monthly
Every feature of Sizzy, billed monthly and cancelable at any time.
Annual$12
per month, billed annually ($15 billed monthly)
Every feature, billed $144 once a year; the page says this saves 20% against monthly.
Lifetime$499
one-time
One payment, with future updates included and every feature unlocked.
Ways to pay less
Responsively App
No public discounts listed.
Sizzy
- Annual discount
Annual billing saves 20%
The pricing page says the annual plan, $144 billed once a year, saves 20% compared with monthly billing.
- Lifetime license
Lifetime license
A $499 one-time payment includes future updates, as stated on the pricing page.
Common questions
Which is cheaper, Responsively App or Sizzy?
As of Nov 13, 2026, Responsively App is cheaper to start with: it is free, against $12 a month for Sizzy. Responsively App is free, and Sizzy starts at $12 per month, billed annually ($15 billed monthly).
Which has a free plan, Responsively App or Sizzy?
As of Nov 13, 2026, only Responsively App has a free plan. Sizzy does not.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.