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APIs · head to head

Kong vs Sphinx

Kong logo

Kong

APIs

Cloud-native API gateway and service connectivity platform

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: Kong the Plus plan includes 1M API requests a month and charges $200 a month for each additional million; Sphinx reStructuredText is harder to write than Markdown and puts off contributors, though MyST now allows Markdown
  • They diverge on capability: Kong covers API Gateway, Sphinx covers Cross-references.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Kong and Sphinx actually diverge.

Attributes where Kong and Sphinx differ
AttributeKongSphinx
Pricing modelsubscriptionOpen source, no licence fee
PlatformsLinux, Docker, KubernetesLinux, macOS, Windows
CategoryAPIsDocumentation
Founded2010Unknown

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

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 Kong

  • API Gateway
  • Authentication & Authorization
  • Rate Limiting
  • Kubernetes
  • Consul
  • Eureka
  • PostgreSQL
  • Linux support

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.

Kong

  • API gateway management and routingnot Sphinx
  • API development and testingnot Sphinx
  • Enterprise API security and governancenot Sphinx

Sphinx

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

Where each one falls short

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

Kong

  • The Plus plan includes 1M API requests a month and charges $200 a month for each additional million
  • Plus is capped at 10M requests a month, so growth past that forces an Enterprise contract
  • Plus limits published APIs to 20 and includes one Developer Portal, with a second at $200 a month
  • SSO and audit logging are Enterprise only
  • Enterprise pricing is custom and billed annually

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

Kong

Free
  • Kong Konnect Free TrialFree
    • 30-day free trial
    • Full enterprise functionality
    • Unlimited gateways
  • Kong Konnect Plus$null/month
    • Per gateway pricing billed monthly
    • Up to 5 Serverless Gateways, 2 Hybrid, 2 Dedicated Cloud Gateways
    • 1M API requests included per month
  • Kong Insomnia EssentialsFree
    • Unlimited projects and CLI access
    • Up to 3 Git Sync users
    • 1,000 mock server requests per month
  • Kong Insomnia Pro$12/month
    • Unlimited users with Git Sync access
    • Unlimited organizations
    • RBAC

Sphinx

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

Which should you pick?

Choose Kong if

  • You need api gateway.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes.
  • You also want authentication & authorization.
Kong 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 Kong or Sphinx better?
Neither clearly leads. Kong 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, Kong or Sphinx?
Kong starts at Free and Sphinx at Free.
Does Kong or Sphinx run on more platforms?
Kong runs on Linux, Docker, Kubernetes. Sphinx runs on Linux, macOS, Windows.
Can I use Kong for free?
Both have a free tier, so you can try either at no cost before committing.
What is Kong best used for?
Kong is most often used for api gateway management and routing, api development and testing, enterprise api security and governance. Of those, api gateway management and routing and api development and testing are not what Sphinx is typically brought in for.
What can Kong do that Sphinx cannot?
Kong covers API Gateway, Authentication & Authorization, Rate Limiting, Kubernetes. Sphinx covers Cross-references, API autodoc, Multi-format output, Extension ecosystem.

Answered from the vendors’ own pages

Kong: Does Kong offer a free trial?

Yes, Kong Konnect offers a 30-day free trial with full enterprise functionality, unlimited gateways, and no credit card required.

Source
Sphinx: Is Sphinx free?

Yes, open source under the BSD licence.

Kong: How much does Kong Insomnia Pro cost?

Kong Insomnia Pro is $12 per user per month with 15% savings available for annual billing.

Source
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.

Kong: What are Kong Konnect Plus API request limits?

Kong Konnect Plus includes 1M API requests per month; additional requests cost $200 per 1M (maximum 10M per month).

Source
Sphinx: Why do large projects choose Sphinx?

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

Kong: What is included in Kong Insomnia Enterprise?

Kong Insomnia Enterprise is $45 per user per month with SSO, SCIM, vault integrations, unlimited mock server requests, and Konnect integration.

Source
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