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Documentation · head to head

Grammarly vs Outline

Grammarly logo

Grammarly

Documentation

Great writing, simplified

From
Free
Rated
-
Full reviewWebsite
Outline logo

Outline

Documentation

Team knowledge base under the Business Source Licence, self-hostable or vendor hosted

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; Outline the Business Source Licence is not an open source licence, so anyone planning to host Outline for clients, resell it or embed it in a commercial service is prohibited until the per-release change date passes, and this is regularly discovered only at legal review.
  • They diverge on capability: Grammarly covers Grammar checking, Outline covers Structured collections.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Grammarly and Outline actually diverge.

Attributes where Grammarly and Outline differ
AttributeGrammarlyOutline
Pricing modelUnknownFree to self-host, per user per month when hosted by the vendor
PlatformsWeb, macOS, Windows, iOS, AndroidWeb, Self-hosted, Docker, iOS, Android
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 Outline

  • Structured collections
  • Block editor
  • Search
  • Backlinks and mentions
  • Templates
  • API and webhooks
  • Single sign-on
  • Self-hosting

What people use each for

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

Grammarly

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

Outline

  • Running an internal wiki on your own infrastructure when documentation cannot leave a specific jurisdictionnot Grammarly
  • Replacing a general-purpose workspace tool with something narrower where search speed and writing flow matter mostnot Grammarly
  • Keeping engineering decision records and postmortems in templated documents that link to each other automaticallynot Grammarly
  • Giving a company already standardised on Google or Okta a wiki that inherits identity and group membership directlynot 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

Outline

  • The Business Source Licence is not an open source licence, so anyone planning to host Outline for clients, resell it or embed it in a commercial service is prohibited until the per-release change date passes, and this is regularly discovered only at legal review.
  • There is no local password authentication, so self-hosting requires an identity provider to be in place first, which turns a small internal wiki into a project with a dependency on Google, Okta, Entra or a Keycloak instance somebody has to run.
  • Self-hosting needs Postgres, Redis and S3-compatible object storage together, so the operational footprint is larger than the single database most internal wikis require.
  • The hosted plans offer no customer-selectable hosting region, so buyers with data residency obligations are pushed to self-hosting even when they would have paid to avoid running servers.
  • It is built for internal knowledge rather than public documentation, with no versioned documentation sets, no static output and limited public publishing, so it will not serve as a product documentation site.
  • Because it is a single-vendor project rather than a foundation-governed one, a future licence or pricing change applies to new releases and the only defence is staying on an older version.

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

Outline

Free
  • Self-hostedFree
    • Source available under the Business Source Licence
    • No licence fee for use inside your own organisation
    • Requires Postgres, Redis and S3-compatible storage
  • Team (hosted)$undefined/month
    • Charged per user per month
    • Hosted and maintained by the vendor
    • Single sign-on through Google, Slack or Microsoft
  • Enterprise (hosted)$undefined/month
    • SAML single sign-on and provisioning
    • Administrative controls and audit visibility
    • Negotiated terms and support

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 Outline if

  • You need structured collections.
  • You want to start without paying.
  • You work on Web, Self-hosted, Docker, iOS, Android.
  • You also want block editor.
Outline review

Questions people ask

Is Grammarly or Outline better?
Neither clearly leads. Grammarly starts at Free and Outline at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Grammarly or Outline?
Grammarly starts at Free and Outline at Free.
Does Grammarly or Outline run on more platforms?
Grammarly runs on Web, macOS, Windows, iOS, Android. Outline runs on Web, Self-hosted, Docker, iOS, Android.
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 Outline is typically brought in for.
What can Grammarly do that Outline cannot?
Grammarly covers Grammar checking, Spelling correction, Punctuation, Clarity suggestions. Outline covers Structured collections, Block editor, Search, Backlinks and mentions.

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
Outline: Is Outline open source?

No, not in the OSI sense. It is source available under the Business Source Licence, which permits internal use and self-hosting but not offering it as a service to others, with each release converting to an open source licence after its change date.

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
Outline: Can I run it for free?

Yes, for your own organisation. Self-hosting carries no licence fee, only the cost of running Postgres, Redis, object storage and an identity provider.

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
Outline: Can I choose where the hosted version stores data?

No. The hosted plans do not offer a region choice, so residency requirements mean self-hosting.

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
Outline: Does it work for public product documentation?

Poorly. It has no versioned documentation sets or static site output, so it is best kept for internal knowledge.

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