Proofly
FreePrivate AI proofreading that runs entirely on-device with Chrome's built-in Gemini Nano.
By Tanmay Verma, Founder · Last verified 03 Jul 2026
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Added 6d ago
69/100MonitorIn short
Proofly — Private AI proofreading that runs entirely on-device with Chrome's built-in Gemini Nano. Best for Privacy-conscious writers who distrust cloud-based tools, Students needing offline proofreading for essays and assignments, Professionals writing sensitive emails or documents on the web. Free to use.
Is Proofly actually worth it?
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Editorial Verdict
Best for
Privacy-conscious writers who distrust cloud-based toolsStudents needing offline proofreading for essays and assignmentsProfessionals writing sensitive emails or documents on the webChrome users who want a lightweight, no-account grammar checker
Not ideal for
Users needing style suggestions, tone analysis, or rewriting capabilitiesWriters on browsers other than Chrome (no Firefox, Edge, Safari support)Users with older Chrome versions (<141) or devices lacking on-device AI supportTeams requiring collaborative proofreading or shared settings
Proofly delivers exactly what it promises: private, local proofreading with no data leaks. It's perfect for Chrome users who prioritize privacy over feature depth, but its limited scope means it won't replace multi-feature assistants like Grammarly.
Compare with: Proofly vs Kagi, Proofly vs Saner, Proofly vs YouMind
Last verified: July 2026
What independent users actually report about Proofly
We ran a structured research pass across product reviews, community discussions, and post-purchase forum threads to surface the patterns vendors won't publish themselves. Below: the recurring strengths, the hidden costs people mention most, and the cohort that consistently regrets adopting this tool.
5 mentions across 2 sources (Hacker News, Product Hunt).
20% positive80% critical
Recurring strengths
- +100% local processing ensures maximum privacy — no data sent.
- +Free and open-source, allowing community audit and customization.
- +Works offline after initial model download, useful for travel.
- +Focused on a single task: proofreading without bloat.
- +Native-feeling UI with popover corrections and sidebar.
Recurring frustrations
- −No community feedback exists to validate its accuracy or reliability.
- −Name collision with another product causes confusion in search.
- −Requires Chrome 141+ — a very recent version limits users.
- −Only spelling, grammar, punctuation — no style or tone analysis.
- −Model download size and impact on device performance unknown.
Patterns worth knowing
Lack of community discussion about proofreading features
Seen on Hacker News, Product Hunt
Product Hunt listing describes a different tool altogether
Seen on Product Hunt
Privacy and offline functionality are highlighted as key differentiators
Seen on Hacker News
Learning curve
beginnerProductive in ~A few hours
Hidden costs people mention
- • No hidden costs; tool is free and open-source.
Viability Score
69/100
MonitorHow likely is Proofly to still be operational in 12 months? Based on 4 signals — momentum (how recently it shipped), wrapper dependency, revenue model, and web presence.
momentum
55
funding runway
40
website health
90
wrapper dependency
100
Last calculated: July 2026
How we score →Key Features
- On-device AI proofreading using Chrome's built-in Gemini Nano
- Real-time underlining of spelling, grammar, punctuation, and capitalization errors
- Native-feeling popover corrections
- Dedicated sidebar for reviewing all issues at once
- Works on input fields, textareas, and contenteditable elements
- Customizable toggle for specific correction types
- Manual trigger mode with configurable keyboard shortcut
- Auto-correct mode
- Zero data transmission – 100% local processing
- No account required, no tracking, no telemetry
- Lightweight and non-invasive UI
- Open-source code
- Works completely offline after initial model download
About Proofly
FreeBeginner-friendlyNo APIPlugin
Proofly is a free, open-source Chrome extension that leverages Chrome's built-in Gemini Nano AI model to provide industry-class proofreading without sending any text to the cloud. It underlines spelling, grammar, punctuation, and capitalization errors as you type, and offers fixes via native-feeling popovers or a dedicated sidebar. All processing happens locally on your device, ensuring complete privacy and offline functionality after the initial model download. Designed for privacy-conscious writers, students, and professionals, Proofly integrates with input fields, textareas, and contenteditable elements across the web. It offers a lightweight, non-invasive UI that respects your focus and page layout. Users can customize which correction types to check, toggle auto-correct or manual trigger modes, and use a configurable keyboard shortcut for on-demand proofreading. Unlike cloud-dependent alternatives like Grammarly, Proofly sends zero data over the network, requires no account, and implements no tracking or telemetry. Its open-source nature (version 0.6.0, updated May 8, 2026) invites community audit and contribution. However, it requires Chrome 141+ and a device capable of running on-device AI models. Proofly is ideal for anyone who values privacy above all else and needs reliable proofreading for emails, messages, documents, and forms. It is not a full-featured writing assistant—it focuses solely on proofreading (spelling, grammar, punctuation) and does not offer style suggestions, tone analysis, or rewriting capabilities.
Behind the Verdict
Proofly nails its core mission: private proofreading. If you're someone who writes sensitive emails or documents and distrusts cloud-based alternatives, this is a no-brainer installation. The fact that it runs entirely on-device via Gemini Nano means zero data ever leaves your machine—and it works offline. No account, no tracking, no telemetry. But Proofly's scope is intentionally narrow. It catches spelling, grammar, punctuation, and capitalization errors, but that's it. There are no tone suggestions, style improvements, or rewriting capabilities. If you need a full-fledged writing assistant, this isn't it. Also, it's Chrome-only and requires version 141+ with on-device AI support, which excludes older devices and other browsers. In practice, we'd use Proofly as a privacy-first companion for everyday writing tasks. It integrates seamlessly and stays out of your way. However, for polished, publication-ready copy, you might still want a more feature-rich tool like Sapling or Grammarly—just be aware of the privacy trade-off. Where it bites: no collaborative features, no cloud sync for custom dictionaries, and the initial model download can be finicky on some hardware. But for a free, open-source tool, it's an impressive demonstration of what on-device AI can do.
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Use Cases
- Proofread emails before sending to ensure professional communication
- Check grammar and spelling in online forms, comments, and social media posts
- Review academic writing in Google Docs or other web-based editors
- Catch errors in sensitive documents without risking data exposure to the cloud
- Use offline when traveling or in areas with unreliable internet
Models Under the Hood
gemini-nano
Limitations
- Proofly requires Chrome 141+ and a device with on-device AI capability.
- It is limited to proofreading (spelling, grammar, punctuation, capitalization) and does not offer rewriting, style suggestions, or tone analysis.
- No API or integrations with other tools are available.
12-month cost
Project the real annual outlay, including the implied monthly cost when only an annual tier is published.
Annual total
Free
Over 12 months
Effective monthly
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Vendor list price only. Add-on usage, seat overages, and contract minimums are surfaced under Hidden costs & gotchas.
Resources & Guides
Frequently Asked Questions
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Common stack mates teams adopt alongside Proofly, with the specific reason each pairing earns its keep.
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