browser extensions / content tools
best content quality checker extensions — 2026.
readability grade alone does not tell you if your post is structurally complete. here is an honest comparison of the best ways to score content quality directly in the browser — without copy-pasting to another tool.
why content quality scoring matters
- readability grade is not enough — short, readable sentences still fail if the post has no subheadings, no images, or a missing internal link structure. a full quality score covers all six axes, not just prose difficulty.
- most editors skip the checklist — by publish time, writers are fatigued and miss structural issues that are easy to catch mechanically: H2 count, alt-text coverage, link density relative to word count.
- copy-pasting breaks your flow — opening Hemingway App, pasting 1,200 words, then switching back to your CMS mid-draft adds friction. a browser extension runs on the page you are already on.
- SEO audits are keyword-first, not quality-first — Yoast and RankMath score for keyword density. rankd scores for content quality regardless of keyword strategy — useful for any post before you add SEO metadata.
the six quality axes rankd scores.
each axis contributes to a composite 0–100 score. all six run locally in your browser on the current page.
Flesch-Kincaid grade level, average sentence length, and passive-voice density.
H1/H2/H3 hierarchy, paragraph density, and logical heading distribution.
word count relative to typical coverage depth for the content type.
internal and external link density relative to content length.
image count and alt-text coverage for accessibility and search discovery.
title length, clarity, and front-loaded keyword position.
the tools compared.
one extension, two standalone tools, and the manual approach.
composite 0–100 content quality score across six axes — runs on the page you are already viewing, no copy-paste needed.
- six-axis quality score: readability, structure, length, links, images, title
- composite 0–100 with ranked improvement suggestions
- scores live pages and draft previews in real time
- nothing sent to any server — scores locally in your browser
- chrome + firefox + edge — no account required
paste your text into a standalone web editor or desktop app to get a reading grade level and a list of highlighted problem sentences.
- sentence-level readability and grade highlighting
- adverb, passive-voice, and complexity highlighting
- requires copy-pasting text out of your CMS
- no link, image, structure, or heading scoring
- no composite score — visual highlighting only
- not a browser extension — no live page scoring
grammar, spelling, and tone assistant with a browser extension — focuses on prose correctness and style, not structural content quality.
- spelling, grammar, and punctuation correction
- tone and clarity suggestions inline
- no content quality score (0–100 composite)
- no heading structure, link density, or image scoring
- account required — free tier is limited
- full features require paid subscription ($12–$15/mo)
feature comparison.
| feature | rankd (free) | Hemingway App | Grammarly | manual checklist |
|---|---|---|---|---|
| composite 0–100 quality score | ✓ yes | ✗ no | ✗ no | ✗ no |
| works in the browser on live pages | ✓ yes | ✗ separate app / tab | ~ inline edits only | ✗ no |
| readability scoring | ✓ Flesch-Kincaid + sentence grade | ✓ grade level | ~ clarity suggestions | ✗ manual |
| heading structure scoring | ✓ H1/H2/H3 hierarchy | ✗ no | ✗ no | ~ manual |
| link density scoring | ✓ internal + external | ✗ no | ✗ no | ~ manual count |
| image + alt-text scoring | ✓ count + alt coverage | ✗ no | ✗ no | ~ manual |
| grammar and spell-check | ✗ not its job | ~ sentence-level flags | ✓ yes | ✗ manual |
| ranked improvement suggestions | ✓ yes — by impact | ~ highlights only | ~ inline suggestions | ✗ no |
| no account required | ✓ yes | ✓ yes (web) | ✗ account required | ✓ n/a |
| available on Firefox + Edge | ✓ yes | ✗ not an extension | ✓ yes | ✓ any browser |
| price | free | free (web) / $19.99 (desktop) | free tier / $12–$15/mo Pro | free (your time) |
verdict by use case.
blog + content writers
rankd
you want a single number that tells you if the post is structurally complete before you hit publish — word count, headings, links, alt text — not just whether the sentences are short.
prose polish and grammar
Grammarly
if the goal is catching spelling errors, awkward phrasing, and grammar mistakes inline as you type, Grammarly is the right tool. it does not score structural quality but it excels at prose correctness.
readability-first editing
Hemingway App
if you want to simplify complex paragraphs and hit a specific grade level, Hemingway's sentence-level highlighting is useful. paste your draft in, fix the red sentences, done. no extension needed.
frequently asked questions.
-
Is there a Chrome extension that scores content quality?
Yes. rankd by vøiddo is a free Chrome, Firefox, and Edge extension that scores any blog post or web content 0–100 across six axes: readability, structure, length, links, images, and title. It runs directly in your browser on any page — no account, no sign-up, no copy-pasting to an external tool.
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How is rankd different from Hemingway App?
Hemingway App is a standalone web editor or desktop application — you copy your text into it to get a readability grade. rankd is a browser extension: it scores the page you are already viewing, including live data like link count, image alt coverage, and heading structure, not just the prose. rankd also produces a composite 0–100 score with six separate axis scores and ranked improvement suggestions, while Hemingway focuses primarily on sentence-level readability.
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How is rankd different from Grammarly?
Grammarly is a grammar and style assistant — it corrects spelling, punctuation, and tone. rankd is a content quality scorer — it does not edit your writing, it scores the structural and readability properties of your published or draft content: word count, heading distribution, link density, image alt text, and readability grade. Grammarly requires an account and subscription for full features; rankd is free with no account required.
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What does rankd actually score?
rankd scores content across six axes, each contributing to a composite 0–100 quality score: readability (Flesch-Kincaid grade level, sentence complexity), structure (H1/H2/H3 distribution, paragraphing), length (word count relative to content type), links (internal and external link density), images (count and alt-text coverage), and title (length, keyword position, clarity).
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Is rankd free?
Yes. The rankd browser extension is completely free. There is no paywall on core scoring and no account required. A rankd web account at rankd.voiddo.com unlocks additional quota for the WordPress plugin and API, but the browser extension scores any page independently and for free.
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Does rankd work on Firefox and Edge?
Yes. rankd is available on Chrome (Chrome Web Store), Firefox (Mozilla Add-ons), and Edge (Microsoft Edge Add-ons). It works on all three major desktop browsers.
install rankd free — score any page in 10 seconds.
composite 0–100 content quality score. six axes. no account, no copy-paste, no cost.
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