Softwr

Cloud · head to head

Caddy vs Prometheus

Caddy logo

Caddy

Cloud

Web server with automatic HTTPS by default

From
Free
Rated
-
Full reviewWebsite
Prometheus logo

Prometheus

Networking

Open source monitoring and alerting toolkit for cloud native environments

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Caddy smaller ecosystem than Nginx, so third-party guides and modules are fewer; Prometheus not suitable for per-request billing as collected data lacks 100% accuracy
  • They diverge on capability: Caddy covers Automatic HTTPS, Prometheus covers Multi-dimensional Data Model.

Where they differ

Only the attributes on which Caddy and Prometheus actually diverge.

Attributes where Caddy and Prometheus differ
AttributeCaddyPrometheus
Pricing modelOpen source, no licence feeopen-source
PlatformsLinux, macOS, Windows, DockerLinux, macOS, Windows
CategoryCloudNetworking
FoundedUnknown2015

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 Caddy

  • Automatic HTTPS
  • Caddyfile
  • Reverse proxy
  • Single binary

Only in Prometheus

  • Multi-dimensional Data Model
  • PromQL Query Language
  • Pull-based Collection
  • Service Discovery
  • Alerting Rules
  • Federation
  • Local Storage
  • Grafana

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 Prometheus
  • Small deployments where Nginx configuration is more effort than the problem warrantsnot Prometheus
  • Reverse proxying internal services with TLS without a certificate workflownot Prometheus

Prometheus

  • Monitoring and alerting systemnot Caddy
  • Time-series databasenot Caddy
  • Infrastructure metrics collectionnot 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

Prometheus

  • Not suitable for per-request billing as collected data lacks 100% accuracy
  • Hard limit on scrape body size; large responses cause scrape failure
  • Per-scrape sample limit enforced; exceeding limit marks targets as failed
  • Not designed for long-term durable storage; optimised for metrics collection

Pricing, plan by plan

Caddy

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

Prometheus

Free
  • Prometheus (Open Source)Free
    • 100% open source
    • Community-driven project
    • Apache 2 License

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 Prometheus if

  • You need multi-dimensional data model.
  • You want to start without paying.
  • You work on Linux, macOS, Windows.
  • You also want promql query language.
Prometheus review

Questions people ask

Is Caddy or Prometheus better?
Neither clearly leads. Caddy starts at Free and Prometheus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Caddy or Prometheus?
Caddy starts at Free and Prometheus at Free.
Does Caddy or Prometheus run on more platforms?
Caddy runs on Linux, macOS, Windows, Docker. Prometheus runs on Linux, macOS, Windows.
Can I use Caddy for free?
Both have a free tier, so you can try either at no cost before committing.
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 Prometheus is typically brought in for.
What can Caddy do that Prometheus cannot?
Caddy covers Automatic HTTPS, Caddyfile, Reverse proxy, Single binary. Prometheus covers Multi-dimensional Data Model, PromQL Query Language, Pull-based Collection, Service Discovery.

Answered from the vendors’ own pages

Caddy: Is Caddy free?

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

Prometheus: What does Prometheus cost?

Prometheus is completely free and open source. There are no pricing tiers or paid plans. The entire project is licensed under Apache 2 and hosted on GitHub.

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.

Prometheus: Is Prometheus commercial software or free?

Prometheus is 100% open source and community-driven. It is a CNCF graduated project with no commercial restrictions or licensing fees.

Source
Caddy: Caddy or Nginx?

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

Prometheus: How is Prometheus licensed?

Prometheus is licensed under the Apache 2 License, which permits free use, modification, and distribution for commercial and non-commercial purposes.

Source
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