Grammarly and its alternatives, sorted into the two jobs they actually do, fixing your writing versus generating new text, with an honest read on what each one can see.
Grammar tools vs AI sidebarsFree tiers comparedPrivacy & clone warnings
The short answer: for grammar and clarity, use Grammarly (most polished) or LanguageTool (open source, privacy-friendly). For generating and rewriting text, use an AI sidebar like Sider, Monica or Perplexity. They're different jobs, don't expect one tool to do both well. Whatever you pick, install only the verified publisher's version: "AI writing" is the most cloned category in the store.
Two categories most lists muddle together
"AI writing extension" lumps together two tools that work nothing alike, and choosing badly means paying for the wrong one. Keep them separate:
Grammar & clarity tools read what you've already written and fix it, spelling, grammar, tone, concision. Grammarly, LanguageTool, Wordtune. They work inline, underlining as you type.
Generative AI sidebars produce new text from a prompt, draft, summarise, answer, translate. Sider, Monica, Perplexity, Compose AI. They work in a side panel next to the page.
If you mostly need to stop sending typo-ridden emails, you want the first kind, and the second is overkill. If you want help drafting from scratch, the first kind won't do it.
The picks at a glance
Tool
Type
Best for
Free tier
Paid from
Privacy note
Grammarly
Grammar
Polished all-round checking
Generous
~$12/mo
Reads all sites
LanguageTool
Grammar
Open source, many languages
Good
~$5/mo
Self-host option
Wordtune
Grammar+
Rewriting & rephrasing
Limited
~$7/mo
Reads all sites
Sider
AI sidebar
Multi-model assistant
Limited daily
~$8/mo
Reads all sites
Monica
AI sidebar
All-in-one AI panel
Limited daily
~$8/mo
Reads all sites
Perplexity
AI sidebar
Sourced answers
Good
~$20/mo
Reads all sites
Compose AI
AI typing
Autocomplete everywhere
Limited
~$10/mo
Reads all sites
Prices as of June 2026 and change often. "Privacy note" reflects the breadth of access the extension requests, not an accusation, see the privacy section below.
How we chose
Each tool had to do a real job well, work under Manifest V3, come from an identifiable publisher, and offer a free tier that's actually usable rather than a teaser. We don't invent quality scores; we weigh what's verifiable, who makes it, what it can access, and what the free tier genuinely includes, and we flag the honest limitation on every pick.
Grammar & clarity tools
Grammarly Freemium
Best for: the most polished all-round checking · Free tier: grammar, spelling, basic clarity · Paid from: ~$12/mo · Works in: Gmail, Docs, LinkedIn, most fields
Still the category leader. Grammarly catches subtle tone and style issues the others miss, and its inline interface is the smoothest. The free tier handles the mistakes that actually embarrass you; Premium adds full-sentence rewrites, tone adjustment and plagiarism checks. The honest limitation: it pushes Premium upsells frequently, and its suggestions can flatten a distinctive voice if you accept them uncritically. Full Grammarly review.
LanguageTool Freemium
Best for: privacy-minded writers and multilingual work · Free tier: solid grammar/spelling, character limit per check · Paid from: ~$5/mo · Open source: yes, self-hostable
The thinking person's Grammarly alternative. LanguageTool is open source, supports more than 30 languages, and can be self-hosted so your text never leaves your own server, the strongest privacy story in this list. The free tier is genuinely useful for everyday checking. The honest limitation: its style and tone suggestions are less sophisticated than Grammarly's, and the free check has a length cap, so very long documents get chunked.
Wordtune Freemium
Best for: rewriting and rephrasing rather than just correcting · Free tier: limited daily rewrites · Paid from: ~$7/mo
Wordtune sits between the two categories: it corrects, but its real strength is offering several rewrites of a sentence so you can pick a clearer or more formal version. Useful for non-native writers and anyone polishing tone. The honest limitation: the free tier's daily rewrite cap is tight, and it's narrower than a full AI sidebar if you also want drafting and summarising.
Generative AI sidebars
Sider Freemium / Monica Freemium
Best for: a do-everything AI panel beside any page · Free tier: a handful of uses per day · Paid from: ~$8/mo
Sider and Monica are close cousins: both put a panel next to the page that can summarise an article, draft a reply, translate, or chat, often letting you switch between several underlying models. For getting AI help without leaving the tab, either works well. The honest limitation: the free tiers are deliberately thin (a few uses a day), and because they can act on whatever you're viewing, they request the broadest access of any tool here, more on that below.
Perplexity Freemium
Best for: answers you can trace to a source · Free tier: generous · Paid from: ~$20/mo
Perplexity's strength is sourced answers, it cites where its information comes from, which makes it more useful for research than a sidebar that just asserts. The extension brings that to any page. The honest limitation: it's an answer engine more than a writing tool, so for drafting and rewriting a dedicated sidebar like Sider fits better.
Compose AI Freemium
Best for: AI autocomplete as you type · Free tier: limited completions · Paid from: ~$10/mo
Compose AI adds Gmail-style predictive autocomplete to text fields across the web, finishing sentences and drafting short replies. Handy for high-volume email. The honest limitation: to autocomplete everywhere it needs to watch your typing on every site, the highest-trust ask for a relatively narrow feature.
The permissions and privacy reality
Here's what nearly every list omits: AI writing extensions are, by design, among the most invasive things you can install. To check or generate text wherever you write, they request "read and change all your data on all websites", and the generative ones often send the page content to a server to process it. That's not automatically sinister; it's how the feature works, and reputable providers handle it as their privacy policy states.
The danger is two-fold:
Confidential text. If you draft anything sensitive, work documents, legal text, client data, understand that a generative tool may transmit it. Check the provider's data-retention policy and your employer's rules. Grammarly and LanguageTool let you turn off processing on specific sites; LanguageTool's self-host option avoids the issue entirely.
Impersonator clones. "AI writing" is the single most spoofed category in the Chrome Web Store. Extensions calling themselves "ChatGPT for Chrome", "Free GPT Assistant" or similar are frequently clones with the real tool's icon and none of its accountability, in 2026 researchers documented a whole cluster of 32 fake AI-assistant add-ons posing as summarisers and Gmail helpers. The brand you trust (OpenAI, Anthropic, Perplexity) publishes under its own verified name; a generic "ChatGPT" extension from an unknown developer is the warning sign.
Before installing any AI writing extension: confirm the publisher is the real company (verified badge, real website), not a soundalike. The combination of all-sites access plus sending your text to a server is exactly the access you don't want in the wrong hands.
Not sure an AI extension is the real thing? Run it through our Extension Safety Checker first, and read the 7 red flags guide on spotting brand-impersonation clones. Free, no account.
Does it work on Firefox, Edge, Brave and Safari?
Grammarly and LanguageTool have the widest reach, with Firefox, Edge and Safari builds alongside Chrome; LanguageTool even offers a standalone and self-hosted setup. The Chromium browsers (Edge, Brave, Opera, Vivaldi) install all of these directly from the Chrome Web Store. The AI sidebars (Sider, Monica, Perplexity) generally cover Chrome, Edge and the Chromium family, with Firefox support varying by tool and thin Safari presence. As always, the safety logic carries across browsers, judge the publisher, not the badge.
Frequently Asked Questions
For grammar and clarity, LanguageTool, open source, usable free tier, the privacy-friendly pick. Grammarly's free tier is also strong if you want the most polished suggestions. For generative help, the free tiers of Sider, Monica or Perplexity give you a few daily uses to test before paying.
Grammarly requests access to read and change text on the sites you write on, inherent to checking your writing everywhere. It's an established company with enterprise deployments, so the access is used as described. The real risk is lookalike clones, install only the verified publisher's version, and check your employer's policy for confidential text.
Grammarly catches more subtle style and tone issues and has the slicker interface. LanguageTool is open source, supports more languages, can be self-hosted, and is better if data privacy matters. For pure error-catching both are strong; LanguageTool wins on transparency, Grammarly on polish.
Grammar and generative tools need to read the text in the fields they work on, and most request access across all sites. Reputable tools process this as described in their privacy policy; the danger is unknown or impersonator extensions with the same permission and no accountability. Treat the all-sites permission as a reason to vet the publisher, not an automatic red flag.
Grammarly, LanguageTool and Wordtune all work inside Gmail and most web text fields; Grammarly and LanguageTool also work in Google Docs. AI sidebars like Sider and Monica work alongside Docs and Gmail as a side panel rather than inline. Check each tool's current Docs support, as it changes.