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APIs · head to head

Kong Gateway vs Sphinx

Kong Gateway logo

Kong Gateway

APIs

Open-source and cloud API gateway for managing microservices traffic

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 Gateway the free open-source gateway lacks the analytics, portals, and support of the paid Konnect tiers.; Sphinx reStructuredText is harder to write than Markdown and puts off contributors, though MyST now allows Markdown
  • They diverge on capability: Kong Gateway covers API request routing, Sphinx covers Cross-references.
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Kong Gateway and Sphinx actually diverge.

Attributes where Kong Gateway and Sphinx differ
AttributeKong GatewaySphinx
Pricing modelfreemiumOpen source, no licence fee
Platformsweb, linux, apiLinux, macOS, Windows
CategoryAPIsDocumentation
Founded2017Unknown

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 Gateway

  • API request routing
  • Plugin ecosystem
  • Developer portals
  • AI Gateway
  • Analytics and observability
  • SSO and audit logs

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 Gateway

  • Routing and securing traffic across microservicesnot Sphinx
  • Publishing internal or external developer portalsnot Sphinx
  • Managing rate limits and authentication at the API edgenot Sphinx
  • Gateway-level routing to multiple LLM providersnot Sphinx

Sphinx

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

Where each one falls short

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

Kong Gateway

  • The free open-source gateway lacks the analytics, portals, and support of the paid Konnect tiers.
  • Plus tier caps API requests at 1M/month before incurring per-million overage charges.
  • Enterprise pricing is custom and not published, making budgeting harder without sales contact.
  • Configuration and plugin management can require significant operational expertise to run at scale.

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 Gateway

Free
  • Free TrialFree
    • 30-day enterprise functionality trial
    • Unlimited gateways
    • 30-day analytics retention
  • Plus$undefined/month
    • Up to 5 serverless, 2 hybrid, 2 dedicated cloud gateways
    • 1M API requests/month included
    • Up to 2 developer portals
  • Enterprise$undefined/month
    • Unlimited hybrid and dedicated cloud gateways
    • Unlimited developer portals
    • SSO and audit logs

Sphinx

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

Which should you pick?

Choose Kong Gateway if

  • You need api request routing.
  • You want to start without paying.
  • You work on web, linux, api.
  • You also want plugin ecosystem.
Kong Gateway 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 Gateway or Sphinx better?
Neither clearly leads. Kong Gateway 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 Gateway or Sphinx?
Kong Gateway starts at Free and Sphinx at Free.
Does Kong Gateway or Sphinx run on more platforms?
Kong Gateway runs on web, linux, api. Sphinx runs on Linux, macOS, Windows.
Can I use Kong Gateway for free?
Both have a free tier, so you can try either at no cost before committing.
What is Kong Gateway best used for?
Kong Gateway is most often used for routing and securing traffic across microservices, publishing internal or external developer portals, managing rate limits and authentication at the api edge, gateway-level routing to multiple llm providers. Of those, routing and securing traffic across microservices and publishing internal or external developer portals are not what Sphinx is typically brought in for.
What can Kong Gateway do that Sphinx cannot?
Kong Gateway covers API request routing, Plugin ecosystem, Developer portals, AI Gateway. Sphinx covers Cross-references, API autodoc, Multi-format output, Extension ecosystem.

Answered from the vendors’ own pages

Kong Gateway: Is Kong Gateway free?

Kong's core gateway is open source and free to self-host. Kong Konnect, the managed cloud platform, offers a 30-day free trial before moving to paid Plus or custom Enterprise pricing.

Source
Sphinx: Is Sphinx free?

Yes, open source under the BSD licence.

Kong Gateway: How is usage metered on the Plus plan?

The Plus plan includes 1M API requests per month, with additional usage billed at $200 per extra 1 million requests up to a 10M/month cap, plus per-gateway and per-LLM-model charges.

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 Gateway: What support is included?

Plus includes email support with a 2-business-day SLA, while Enterprise adds dedicated success managers and professional services.

Source
Sphinx: Why do large projects choose Sphinx?

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

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