Firefox vs SeaMonkey (2026): which should you pick?
As of Nov 13, 2026, we pick Firefox: it is third in our ranking of browsers, and it grades higher too, 3.8 against 3.0.
Checked Oct 5, 2026 and Nov 13, 2026 · graded Oct 10, 2026 and Nov 13, 2026 by ToolGPA
Firefox grades higher on features and platforms. They get the same grade on value for money, the free plan and ease of use.
Price, platforms and features side by side. The table says where each price was read and when.
Firefox
Free, open-source browser from Mozilla with tracker blocking built in
Free
SeaMonkey
All-in-one internet suite with browser, mail, chat and HTML editor
Free
Which one is for you
Pick Firefox if
- Fits if you want trackers blocked from day one without touching a setting
- Works for people who hop between Windows, Mac, Linux and a phone
Look elsewhere if
- Skip it if you want the VPN on your phone, as the built-in one is desktop only for now
- Tight if you'd keep the VPN on all day, since it's capped at 50 GB a month and covers the browser only
- Pricey if you want a whole-device VPN, as Mozilla's separate service is $9.99 a month or $59.88 a year
- Watch out: the homepage shows ads to fund development until you switch them off
- Not for you if you're on Windows 8.1 or macOS 10.14 or older, which need Firefox ESR
Pick SeaMonkey if
- Fits if you want browser, mail and IRC in one desktop program
- Makes sense if you read newsgroups or edit HTML pages by hand
Look elsewhere if
- Skip it if you want a phone version, as the site offers no iOS or Android edition
- Not for you if you use an Apple silicon Mac, since only an x64 macOS build is listed
- Watch out: the current release listed is 2.53.24, built on the Gecko engine
- Too heavy if you only want to browse, since mail, chat and editor come along
How we grade them
| 3.8GPAFirefoxExcellent | 3.0GPASeaMonkeyVery good | |
|---|---|---|
| Value for money | AFree, with no paid tier at all. Mozilla sells a separate VPN service at $59.88 a year, but the browser is whole without it and nothing in it is held back for payers. | AFree, with donations and sponsors accepted and no paid plan, so it undercuts this category's $7 cheapest quarter. |
| Free plan and trial | AFree outright, with tracker blocking, end-to-end encrypted sync, the PDF editor, translation, and a VPN for 50 GB a month on the desktop. The Mozilla account sync needs is free, and the homepage ads can be switched off. | AThe whole suite for Windows, macOS and Linux downloads at no charge, in 20-plus languages. |
| Features | AIt covers the job on its own Gecko engine rather than Chromium. Known trackers blocked by default, each site's cookies kept apart, tab groups and vertical tabs, a sidebar where you pick ChatGPT, Gemini, Claude or Copilot, reader mode, PDF filling and signing, translation done on your machine. | CBrowser, mail and news, feeds, IRC and an HTML editor in one program, built on Gecko. The browser itself is the same size of job as any other. |
| Ease of use | B4.65 from about 218,000 App Store ratings, below the 4.8 at the top of this category. Nothing needs configuring: blocking is on from the start and the shield in the address bar shows what it caught. | BNo rating on record. It is a program you install and start using, though a suite has more parts than a lone browser. |
| Platforms and integrations | AAll five: Windows, Mac, Linux, Android and iPhone, with bookmarks, history, passwords and tabs synced end-to-end encrypted, and Send Tab to throw a page at another device. Only the built-in VPN is missing from the phone apps. | CWindows x64 and x86, macOS x64 and Linux x64 and x86 builds, with no Android or iOS edition. |
| Best for | a free browser that isn't built on Chromium | an all-in-one browser, mail and chat suite |
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: Firefox and SeaMonkey. How we grade
Price against what you get
Firefox has no paid plan and scores 3.7 out of 4 on features, ease of use and platforms. SeaMonkey has no paid plan and scores 2.3.
Firefox scores higher for the same starting price. Of the other browsers on the chart, none scores higher than Firefox for less, and none scores higher than SeaMonkey 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
- Firefox is end-to-end encrypted, according to its own site.
- Firefox also covers password manager.
- SeaMonkey also covers email client and rSS reader.
In commonFree planWindowsmacOSLinuxOpen sourceWeb browser
At a glance
| Firefox | SeaMonkey | |
|---|---|---|
| Pricing | Free | Free |
| Starts at | Free | Free |
| Free plan | The browser is free with no paid tier. The built-in VPN is free for up to 50 GB of browser traffic per month, and sync uses a free Mozilla account. | SeaMonkey is free; the site accepts donations and sponsors and lists no paid plan. |
| Free trial | None listed | None listed |
| macOS | ||
| Windows | ||
| Linux | ||
| iOS | ||
| Android | ||
| Made by | Mozilla Corporation | SeaMonkey Association |
| Price read from | firefox.com | seamonkey-project.org |
| Checked | Oct 5, 2026 | Nov 13, 2026 |
Worth knowing
Firefox
- The built-in VPN is capped at 50 GB per month and protects browser traffic only. Mozilla's paid VPN service costs $59.88 per year or $9.99 per month, plus tax.
- Firefox shows optional ads on its homepage to fund development. They can be turned off.
- The built-in VPN has not reached Firefox for Android or iOS; Mozilla's roadmap lists VPN on mobile as upcoming work.
- Windows 8.1 and below and macOS 10.14 and below are no longer supported by the standard release; they need Firefox ESR.
SeaMonkey
- The listed macOS build is x64 only; no ARM-specific macOS build is shown.
- It is run by a community council, and the about page says it describes the only full internet suite still developed.
- The current release listed is 2.53.24, built on the Gecko engine.
- The site offers no iOS or Android edition.
Key features
Firefox
- Tracking and cookie protection
- Enhanced Tracking Protection blocks known trackers by default, and Total Cookie Protection keeps each site's cookies separate. The shield icon in the address bar shows what was blocked.
- Built-in VPN
- A VPN toggle in the desktop toolbar routes browser traffic through a proxy server to hide the IP address, free for up to 50 GB per month. It covers the browser only, not other apps on the device.
- Tab groups, vertical tabs and sidebar
- Tabs can be grouped and color coded or stacked vertically, and a customizable sidebar gives one-click access to bookmarks, history, synced tabs and other tools.
- AI chatbots in the sidebar
- The sidebar can host a third-party assistant such as ChatGPT, Gemini, Copilot, Claude or Mistral Chat. AI features are optional and can be turned off entirely.
- Sync with a Mozilla account
- Bookmarks, history, saved passwords and open tabs sync across desktop and mobile with end-to-end encryption, and Send Tab pushes a page from one device to another.
- Reader mode, PDF editor and translation
- Reader mode strips clutter from articles, a built-in editor fills, signs and annotates PDFs, and pages are translated in the browser without sharing the data with anyone else.
SeaMonkey
- Browser
- An Internet browser built on Gecko, the same code behind Thunderbird and the base of Firefox.
- Email and newsgroups
- A built-in mail and newsgroup client, plus feed reading, per the site's one-line description.
- IRC chat
- Chat is included in the same application as the browser and mail.
- HTML editor and web development tools
- An HTML editor and web development tools are part of the suite.
- Multiple languages and platforms
- The download table lists Windows x64 and x86, macOS x64, and Linux x64 and x86 builds in many languages.
Plans
Firefox
Free$0
The full browser on Windows, macOS, Linux, Android and iOS, including tracker blocking, sync and, on desktop, the built-in VPN up to 50 GB a month.
SeaMonkey
Free$0
The full suite for Windows, macOS and Linux, in 20-plus languages.
Common questions
Which is cheaper, Firefox or SeaMonkey?
As of Nov 13, 2026, both Firefox and SeaMonkey are free to use.
Which has a free plan, Firefox or SeaMonkey?
As of Nov 13, 2026, both Firefox and SeaMonkey have a free plan.
Which platforms do Firefox and SeaMonkey run on?
As of Nov 13, 2026, only Firefox lists iOS and Android apps. Both list macOS, Windows and Linux apps. A platform missing from a listing is one its maker's pages did not mention.
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.