Softwr

Documentation · head to head

Outline vs Sphinx

Outline logo

Outline

Documentation

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

From
Free
Rated
-
Full reviewWebsite
Sphinx logo

Sphinx

Documentation

Documentation generator built for large technical projects

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: 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.; Sphinx reStructuredText is harder to write than Markdown and puts off contributors, though MyST now allows Markdown
  • They diverge on capability: Outline covers Structured collections, Sphinx covers Cross-references.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Outline and Sphinx actually diverge.

Attributes where Outline and Sphinx differ
AttributeOutlineSphinx
Pricing modelFree to self-host, per user per month when hosted by the vendorOpen source, no licence fee
PlatformsWeb, Self-hosted, Docker, iOS, AndroidLinux, macOS, Windows

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 Outline

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

Only in Sphinx

  • Cross-references
  • API autodoc
  • Multi-format output
  • Extension ecosystem

What people use each for

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

Outline

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

Sphinx

  • Large technical documentation needing reliable cross-referencesnot Outline
  • Python projects generating API docs from docstringsnot Outline
  • Documentation that must ship as PDF as well as HTMLnot Outline

Where each one falls short

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

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.

Sphinx

  • reStructuredText is harder to write than Markdown and puts off contributors, though MyST now allows Markdown
  • Configuration is complex and the default output is dated-looking without theme work
  • Build times on large documentation sets are slow
  • Heavier than the problem for a small project that only needs a few pages

Pricing, plan by plan

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

Sphinx

Free
  • SphinxFree
    • Full functionality
    • Commercial use permitted
    • Community support

Which should you pick?

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

Choose Sphinx if

  • You need cross-references.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want api autodoc.
Sphinx review

Questions people ask

Is Outline or Sphinx better?
Neither clearly leads. Outline starts at Free and Sphinx at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Outline or Sphinx?
Outline starts at Free and Sphinx at Free.
Does Outline or Sphinx run on more platforms?
Outline runs on Web, Self-hosted, Docker, iOS, Android. Sphinx runs on Linux, macOS, Windows.
Can I use Outline for free?
Both have a free tier, so you can try either at no cost before committing.
What is Outline best used for?
Outline is most often used for running an internal wiki on your own infrastructure when documentation cannot leave a specific jurisdiction, replacing a general-purpose workspace tool with something narrower where search speed and writing flow matter most, keeping engineering decision records and postmortems in templated documents that link to each other automatically, giving a company already standardised on google or okta a wiki that inherits identity and group membership directly. Of those, running an internal wiki on your own infrastructure when documentation cannot leave a specific jurisdiction and replacing a general-purpose workspace tool with something narrower where search speed and writing flow matter most are not what Sphinx is typically brought in for.
What can Outline do that Sphinx cannot?
Outline covers Structured collections, Block editor, Search, Backlinks and mentions. Sphinx covers Cross-references, API autodoc, Multi-format output, Extension ecosystem.

Answered from the vendors’ own pages

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.

Sphinx: Is Sphinx free?

Yes, open source under the BSD licence.

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.

Sphinx: Do I have to write reStructuredText?

Not any more. The MyST extension allows Markdown, though reStructuredText remains the native format and most examples use it.

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.

Sphinx: Why do large projects choose Sphinx?

Automatic cross-referencing and API extraction from docstrings, which lighter generators do not provide.

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.

Share

Related pages

More on Outline

More on Sphinx

Keep looking

Other head to heads