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Cloud · head to head

Caddy vs GNAT Pro

Caddy logo

Caddy

Cloud

Web server with automatic HTTPS by default

From
Free
Free plan
Yes
Full reviewWebsite
GNAT Pro logo

GNAT Pro

Developer Tools

Software development environments and toolchains for Ada, C/C++ and Rust

From
On request
Free plan
No
Full reviewWebsite

The short version

  • Only Caddy has a free tier, so it costs nothing to try first.
  • Each has a real cost: Caddy smaller ecosystem than Nginx, so third-party guides and modules are fewer; GNAT Pro no pricing published on website; requires contacting AdaCore directly for quotes
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which Caddy and GNAT Pro actually diverge.

Attributes where Caddy and GNAT Pro differ
AttributeCaddyGNAT Pro
Starting priceFreeOn request
Pricing modelOpen source, no licence feequote
Free tierYesNo
PlatformsLinux, macOS, Windows, DockerWeb
CategoryCloudDeveloper Tools

Identical on both: 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 Caddy

  • Automatic HTTPS
  • Caddyfile
  • Reverse proxy
  • Single binary

Only in GNAT Pro

Nothing recorded that Caddy does not also cover.

What people use each for

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

Caddy

  • Sites and services where expired certificates have caused outages beforenot GNAT Pro
  • Small deployments where Nginx configuration is more effort than the problem warrantsnot GNAT Pro
  • Reverse proxying internal services with TLS without a certificate workflownot GNAT Pro

GNAT Pro

  • Building certified avionics software meeting DO-178B/C standardsnot Caddy
  • Developing automotive embedded systems with ISO-26262 compliancenot Caddy
  • Integrating Ada, C/C++, and Rust components in single codebasenot Caddy
  • Managing software supply chain vulnerabilities and SBOMsnot Caddy
  • Supporting long-lived software systems spanning decadesnot Caddy

Where each one falls short

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

Caddy

  • Smaller ecosystem than Nginx, so third-party guides and modules are fewer
  • Adding plugins means rebuilding the binary rather than loading a module
  • Under very high throughput Nginx generally still benchmarks ahead
  • Automatic certificate issuance needs outbound internet access, which complicates air-gapped deployments

GNAT Pro

  • No pricing published on website; requires contacting AdaCore directly for quotes
  • Vendor indicates per-user, per-year subscription model but does not disclose specific costs

Pricing, plan by plan

Caddy

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

GNAT Pro

On request

No published plan breakdown. See the GNAT Pro review.

Which should you pick?

Choose Caddy if

  • You need automatic https.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Docker.
  • You also want caddyfile.
Caddy review

Choose GNAT Pro if

Nothing in the data separates GNAT Pro from Caddy on the points above - pick on price and on how each one feels to use.

GNAT Pro review

Questions people ask

Is Caddy or GNAT Pro better?
Neither clearly leads. Caddy starts at Free and GNAT Pro at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Caddy or GNAT Pro?
Caddy has a free tier; the other does not. Paid plans start at Free for Caddy and On request for GNAT Pro.
Does Caddy or GNAT Pro run on more platforms?
Caddy runs on Linux, macOS, Windows, Docker. GNAT Pro runs on Web.
Can I use Caddy for free?
Yes. Caddy has a free tier, so you can try it without paying. GNAT Pro starts at On request.
What is Caddy best used for?
Caddy is most often used for sites and services where expired certificates have caused outages before, small deployments where nginx configuration is more effort than the problem warrants, reverse proxying internal services with tls without a certificate workflow. Of those, sites and services where expired certificates have caused outages before and small deployments where nginx configuration is more effort than the problem warrants are not what GNAT Pro is typically brought in for.
What can Caddy do that GNAT Pro cannot?
Caddy covers Automatic HTTPS, Caddyfile, Reverse proxy, Single binary.

Answered from the vendors’ own pages

Caddy: Is Caddy free?

Yes, open source under the Apache 2.0 licence, free for commercial use.

GNAT Pro: How much does GNAT Pro cost?

GNAT Pro pricing is not published on the website. Customers must request a pricing quote by contacting AdaCore directly or speaking with a GNAT Pro expert.

Source
Caddy: What does automatic HTTPS mean?

Caddy obtains certificates from Let’s Encrypt or ZeroSSL on first request and renews them before expiry, with no cron job or configuration.

GNAT Pro: What is GNAT Pro licensing model?

GNAT Pro is sold on a per-user, per-year basis with no license locks. Customers can request pricing for their specific needs.

Source
Caddy: Caddy or Nginx?

Caddy is dramatically simpler to configure and removes certificate management. Nginx has the larger ecosystem and better peak throughput.

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