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Documentation · head to head

Grammarly vs Scalar

Grammarly logo

Grammarly

Documentation

Great writing, simplified

From
Free
Rated
-
Full reviewWebsite
Scalar logo

Scalar

Documentation

Open source API reference renderer and request client generated entirely from an OpenAPI document

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Grammarly occasional false positives and grammatically incorrect suggestions that can introduce errors; Scalar it documents only what an OpenAPI document can express, so guides, authentication walkthroughs and conceptual pages need a second tool and a second navigation.
  • They diverge on capability: Grammarly covers Grammar checking, Scalar covers OpenAPI driven reference.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Grammarly and Scalar actually diverge.

Attributes where Grammarly and Scalar differ
AttributeGrammarlyScalar
Pricing modelUnknownOpen source, no licence fee
PlatformsWeb, macOS, Windows, iOS, AndroidWeb, macOS, Windows, Linux
Founded2009Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Documentation).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Grammarly

  • Grammar checking
  • Spelling correction
  • Punctuation
  • Clarity suggestions
  • Engagement feedback
  • Delivery insights
  • Plagiarism checker
  • Citation generator

Only in Scalar

  • OpenAPI driven reference
  • Embedded API client
  • Generated code samples
  • Framework adapters
  • Themeable renderer
  • Self hostable
  • Spec validation

What people use each for

The jobs each tool is most often brought in to do.

Grammarly

  • Email writingnot Scalar
  • Document editingnot Scalar
  • Academic writingnot Scalar
  • Business communicationnot Scalar
  • Content creationnot Scalar

Scalar

  • Replacing default Swagger UI on a public API without moving to a hosted documentation vendornot Grammarly
  • A framework that already emits an OpenAPI document and needs a reference page mounted on a routenot Grammarly
  • An internal API portal that must run inside a private network with no external callsnot Grammarly
  • A team that wants readers to make authenticated test calls without leaving the reference pagenot Grammarly

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Grammarly

  • Occasional false positives and grammatically incorrect suggestions that can introduce errors
  • Privacy concerns about sending text to Grammarly's servers for analysis
  • AI capabilities sometimes produce hallucinations and fabricated citations that appear grammatically correct

Scalar

  • It documents only what an OpenAPI document can express, so guides, authentication walkthroughs and conceptual pages need a second tool and a second navigation.
  • The output is only as good as the spec, so an API with thin descriptions and missing examples produces a thin reference and the tool cannot compensate.
  • Deep visual customisation goes beyond the theme variables quickly, and matching an existing brand often means overriding styles against internal class names that can change.
  • Running the embedded client against a production API invites readers to send real requests, which means rate limits, test accounts and CORS configuration become your problem.
  • The open source renderer and the hosted platform advance at different rates, so a feature seen in a demo is not necessarily in the package you self host.

Pricing, plan by plan

Grammarly

Free
  • FreeFree
    • Basic grammar and spelling checks
    • Tone visibility
    • 100 AI prompts per month
  • Pro$12/month
    • Sentence rewrites
    • Tone adjustment
    • Plagiarism and AI detection

Scalar

Free
  • Open source rendererFree
    • MIT licence, no fee for the renderer
    • Embedded request client
    • Framework adapters

Which should you pick?

Choose Grammarly if

  • You need grammar checking.
  • You want to start without paying.
  • You work on Web, macOS, Windows, iOS, Android.
  • You also want spelling correction.
Grammarly review

Choose Scalar if

  • You need openapi driven reference.
  • You want to start without paying.
  • You work on Web, macOS, Windows, Linux.
  • You also want embedded api client.
Scalar review

Questions people ask

Is Grammarly or Scalar better?
Neither clearly leads. Grammarly starts at Free and Scalar at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Grammarly or Scalar?
Grammarly starts at Free and Scalar at Free.
Does Grammarly or Scalar run on more platforms?
Grammarly runs on Web, macOS, Windows, iOS, Android. Scalar runs on Web, macOS, Windows, Linux.
Can I use Grammarly for free?
Both have a free tier, so you can try either at no cost before committing.
What is Grammarly best used for?
Grammarly is most often used for email writing, document editing, academic writing, business communication. Of those, email writing and document editing are not what Scalar is typically brought in for.
What can Grammarly do that Scalar cannot?
Grammarly covers Grammar checking, Spelling correction, Punctuation, Clarity suggestions. Scalar covers OpenAPI driven reference, Embedded API client, Generated code samples, Framework adapters.

Answered from the vendors’ own pages

Grammarly: Does Grammarly have a free version?

Yes, Grammarly offers a free tier with basic spelling, grammar, and punctuation checks, tone visibility, and 100 AI prompts per month. The Pro plan ($12/month annual) adds sentence rewriting, plagiarism detection, and 2,000 AI prompts.

Source
Scalar: Can I use it without paying anything?

Yes. The renderer is open source and self hostable. The hosted platform is a separate paid product.

Grammarly: What platforms does Grammarly work with?

Grammarly works across 1 million+ apps including Google Docs, Microsoft Word, Outlook, Slack, Gmail, and web browsers. It also integrates with productivity tools like Asana, Jira, Monday.com, Confluence, and HubSpot.

Source
Scalar: Does it replace a full documentation site?

No. It covers API reference. Guides and concepts need a general documentation generator alongside it.

Grammarly: Can I use Grammarly offline?

Grammarly requires an internet connection to function, though the browser extension works with some offline text areas. For offline use, the desktop app and browser extensions sync when reconnected.

Source
Scalar: Will my reference go out of date?

Only if your OpenAPI document does. The reference is generated, so there is no second copy to forget.

Grammarly: What is included in the Enterprise plan?

The Enterprise plan includes unlimited team members, dedicated support, custom roles and permissions, data loss prevention, bring-your-own-key encryption, and unlimited AI prompts. Pricing is custom and available by contacting sales.

Source
Scalar: Does the embedded client send real requests?

Yes, from the reader browser. Plan for CORS, rate limits and a sandbox environment before publishing.

Scalar: What if my API has no OpenAPI document?

Then this is the wrong tool. Producing an accurate spec is the prerequisite, not an optional step.

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