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Documentation · head to head

Scalar vs Starlight

Scalar logo

Scalar

Documentation

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

From
Free
Rated
-
Full reviewWebsite
Starlight logo

Starlight

Documentation

Documentation site framework built on Astro that ships no JavaScript to the reader by default

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: 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.; Starlight there is no editing interface, so every correction requires a git client, a Node install and a CI run, which puts documentation changes out of reach for anyone who does not already work in a repository.
  • They diverge on capability: Scalar covers OpenAPI driven reference, Starlight covers File based routing.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Scalar and Starlight actually diverge.

Attributes where Scalar and Starlight differ
AttributeScalarStarlight

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), platforms (Web, macOS, Windows, Linux), 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 Scalar

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

Only in Starlight

  • File based routing
  • Pagefind search
  • Internationalisation
  • Component overrides
  • Zero client JavaScript
  • Expressive Code blocks
  • Auto generated sidebar

What people use each for

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

Scalar

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

Starlight

  • A developer tool whose docs live in the same repository as the code and are reviewed in the same pull requestnot Scalar
  • A team that already runs Astro for its marketing site and wants one build pipeline for bothnot Scalar
  • Documentation that must be served from a CDN or an air gapped static host with no search backendnot Scalar
  • A multilingual open source project that needs per locale content trees and untranslated page fallbacknot Scalar

Where each one falls short

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

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.

Starlight

  • There is no editing interface, so every correction requires a git client, a Node install and a CI run, which puts documentation changes out of reach for anyone who does not already work in a repository.
  • Starlight versions track Astro versions, so an Astro major release becomes a documentation site migration on someone else timeline rather than yours.
  • Pagefind builds the whole search index at compile time, so build duration and index size grow with page count and large documentation sets pay for it on every deploy.
  • There is no analytics, no feedback widget and no page level rating built in, so measuring which pages fail readers means wiring a third party script yourself.
  • Component overrides are limited to the slots the theme exposes, and anything outside those slots means forking the theme and inheriting the merge burden on every upgrade.

Pricing, plan by plan

Scalar

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

Starlight

Free
  • Open sourceFree
    • MIT licence
    • All features included
    • Self hosted on any static host

Which should you pick?

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

Choose Starlight if

  • You need file based routing.
  • You want to start without paying.
  • You work on Web, macOS, Windows, Linux.
  • You also want pagefind search.
Starlight review

Questions people ask

Is Scalar or Starlight better?
Neither clearly leads. Scalar starts at Free and Starlight at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Scalar or Starlight?
Scalar starts at Free and Starlight at Free.
Does Scalar or Starlight run on more platforms?
Both run on Web, macOS, Windows, Linux, so platform support will not decide this one for you.
Can I use Scalar for free?
Both have a free tier, so you can try either at no cost before committing.
What is Scalar best used for?
Scalar is most often used for replacing default swagger ui on a public api without moving to a hosted documentation vendor, a framework that already emits an openapi document and needs a reference page mounted on a route, an internal api portal that must run inside a private network with no external calls, a team that wants readers to make authenticated test calls without leaving the reference page. Of those, replacing default swagger ui on a public api without moving to a hosted documentation vendor and a framework that already emits an openapi document and needs a reference page mounted on a route are not what Starlight is typically brought in for.
What can Scalar do that Starlight cannot?
Scalar covers OpenAPI driven reference, Embedded API client, Generated code samples, Framework adapters. Starlight covers File based routing, Pagefind search, Internationalisation, Component overrides.

Answered from the vendors’ own pages

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.

Starlight: Can a non technical writer publish a page without help?

No. There is no content management interface. Every change is a commit, a pull request and a build.

Scalar: Does it replace a full documentation site?

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

Starlight: Do I need to know Astro to use it?

Not for basic use. Markdown files and a config file are enough until you want custom components, at which point Astro knowledge becomes mandatory.

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.

Starlight: Is search included or do I pay for it?

Included and free. Pagefind builds a static index at compile time. Algolia DocSearch is optional if you want hosted search instead.

Scalar: Does the embedded client send real requests?

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

Starlight: What happens when Astro releases a major version?

Starlight follows it, and your site needs a migration. Read the upgrade guide before pinning a version for a long lived project.

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.

Starlight: Can I self host with no external services?

Yes. The output is static HTML, CSS and a search index. Nothing calls out at runtime unless you add it.

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