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Documentation · head to head

Doxygen vs Kong

Doxygen logo

Doxygen

Documentation

Free, open source documentation generator that builds reference docs from source code comments

From
Free
Rated
-
Full reviewWebsite
Kong logo

Kong

APIs

Cloud-native API gateway and service connectivity platform

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Doxygen there is no vendor or paid support contract; when something breaks in a large or unusual codebase, the only recourse is community mailing lists, forums or reading the source; Kong the Plus plan includes 1M API requests a month and charges $200 a month for each additional million
  • They diverge on capability: Doxygen covers Code comment parsing, Kong covers API Gateway.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Doxygen and Kong actually diverge.

Attributes where Doxygen and Kong differ
AttributeDoxygenKong
Pricing modelOpen source, no licence feesubscription
PlatformsLinux, macOS, WindowsLinux, Docker, Kubernetes
CategoryDocumentationAPIs
FoundedUnknown2010

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 Doxygen

  • Code comment parsing
  • Multi-format output
  • Call and inheritance graphs
  • Markdown support
  • CI-friendly build

Only in Kong

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

What people use each for

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

Doxygen

  • An engineering team generating API reference documentation directly from source code comments as part of a CI buildnot Kong
  • A library or SDK maintainer who wants reference docs that cannot drift out of sync with the code because they are generated from itnot Kong
  • An internal platform team documenting a large C++ or Java codebase where structure like class hierarchies and call graphs matters more than prosenot Kong
  • A project with no documentation budget that still needs professional-looking reference output without any licence costnot Kong

Kong

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

Where each one falls short

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

Doxygen

  • There is no vendor or paid support contract; when something breaks in a large or unusual codebase, the only recourse is community mailing lists, forums or reading the source
  • Default HTML output looks dated and requires a third-party theme such as Doxygen Awesome to look acceptable to a modern audience, which is extra setup work not included
  • It only generates reference documentation from code comments; it is not a narrative documentation tool, help centre or CCMS, so most teams need a separate tool for guides and tutorials
  • Comment syntax and configuration have a real learning curve, and inconsistent comment discipline across a team produces inconsistent or sparse output regardless of the tool
  • Multi-language support varies in depth; parsing quality for languages outside its C-family core (C++, C, C#, Objective-C) is generally weaker than for its primary targets
  • There is no built-in hosting, search analytics, or reader-facing help centre features, so publishing the generated docs anywhere usable still requires separate infrastructure

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

Pricing, plan by plan

Doxygen

Free
  • DoxygenFree
    • Full functionality
    • No usage limits
    • Community mailing list and GitHub issue support

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

Which should you pick?

Choose Doxygen if

  • You need code comment parsing.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want multi-format output.
Doxygen review

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

Questions people ask

Is Doxygen or Kong better?
Neither clearly leads. Doxygen starts at Free and Kong at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Doxygen or Kong?
Doxygen starts at Free and Kong at Free.
Does Doxygen or Kong run on more platforms?
Doxygen runs on Linux, macOS, Windows. Kong runs on Linux, Docker, Kubernetes.
Can I use Doxygen for free?
Both have a free tier, so you can try either at no cost before committing.
What is Doxygen best used for?
Doxygen is most often used for an engineering team generating api reference documentation directly from source code comments as part of a ci build, a library or sdk maintainer who wants reference docs that cannot drift out of sync with the code because they are generated from it, an internal platform team documenting a large c++ or java codebase where structure like class hierarchies and call graphs matters more than prose, a project with no documentation budget that still needs professional-looking reference output without any licence cost. Of those, an engineering team generating api reference documentation directly from source code comments as part of a ci build and a library or sdk maintainer who wants reference docs that cannot drift out of sync with the code because they are generated from it are not what Kong is typically brought in for.
What can Doxygen do that Kong cannot?
Doxygen covers Code comment parsing, Multi-format output, Call and inheritance graphs, Markdown support. Kong covers API Gateway, Authentication & Authorization, Rate Limiting, Kubernetes.

Answered from the vendors’ own pages

Doxygen: Is Doxygen really free with no paid tier?

Yes, it is GPL-licensed open source software with no company selling licences or support contracts.

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
Doxygen: Does Doxygen write documentation for me?

No, it extracts and formats documentation from comments a developer has already written in the source code; it does not generate prose from uncommented code.

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
Doxygen: Can it produce anything besides reference documentation?

It can render standalone markdown pages alongside the generated reference content, but it is not a general authoring or publishing platform.

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
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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