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Cloud · head to head

Caddy vs DuckDB

Caddy logo

Caddy

Cloud

Web server with automatic HTTPS by default

From
Free
Rated
-
Full reviewWebsite
DuckDB logo

DuckDB

Databases

MIT-licensed analytical SQL database that runs inside your process, with no server, no dependencies and one writer at a time.

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; DuckDB a database file accepts one read-write process at a time; other processes must open it read-only and will not see subsequent writes, so DuckDB cannot be the shared database behind several services.
  • They diverge on capability: Caddy covers Automatic HTTPS, DuckDB covers In-process execution.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Caddy and DuckDB actually diverge.

Attributes where Caddy and DuckDB differ
AttributeCaddyDuckDB
Pricing modelOpen source, no licence feeopen-source
PlatformsLinux, macOS, Windows, DockerLinux, macOS, Windows, WebAssembly
CategoryCloudDatabases
FoundedUnknown2019

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 DuckDB

  • In-process execution
  • Vectorised columnar engine
  • Direct file querying
  • Zero dependencies
  • Larger-than-memory queries
  • MIT licence
  • Postgres-flavoured SQL
  • Extension ecosystem

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

DuckDB

  • Transformation steps in a data pipeline that would otherwise need Spark, replaced by SQL over Parquet in a single processnot Caddy
  • Analytical queries embedded in an application or a dashboard where shipping a database server alongside it is not acceptablenot Caddy
  • Local exploration of files that are too large for a pandas dataframe but far too small to justify a warehousenot Caddy
  • Continuous integration and testing of analytical SQL, where a real engine can run in the test process without provisioning anythingnot 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

DuckDB

  • A database file accepts one read-write process at a time; other processes must open it read-only and will not see subsequent writes, so DuckDB cannot be the shared database behind several services.
  • There is no network protocol, authentication or user management, so exposing it to remote clients means writing and securing your own service around it.
  • It is built for scans and aggregations, not for many small transactions, so a workload of high-frequency single-row inserts and updates performs badly compared with SQLite or Postgres.
  • Storage files are backwards compatible but not forwards compatible, so a file written by a newer version cannot be read by an older one and every consumer of a shared file must be upgraded together.
  • Query memory settings matter: some operations still need to hold significant state, so an under-configured memory limit turns a large join or a high-cardinality aggregation into a spill-heavy query or an out-of-memory failure rather than a slow success.

Pricing, plan by plan

Caddy

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

DuckDB

Free

No published plan breakdown. See the DuckDB 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 DuckDB if

  • You need in-process execution.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, WebAssembly.
  • You also want vectorised columnar engine.
DuckDB review

Questions people ask

Is Caddy or DuckDB better?
Neither clearly leads. Caddy starts at Free and DuckDB at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Caddy or DuckDB?
Caddy starts at Free and DuckDB at Free.
Does Caddy or DuckDB run on more platforms?
Caddy runs on Linux, macOS, Windows, Docker. DuckDB runs on Linux, macOS, Windows, WebAssembly.
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 DuckDB is typically brought in for.
What can Caddy do that DuckDB cannot?
Caddy covers Automatic HTTPS, Caddyfile, Reverse proxy, Single binary. DuckDB covers In-process execution, Vectorised columnar engine, Direct file querying, Zero dependencies.

Answered from the vendors’ own pages

Caddy: Is Caddy free?

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

DuckDB: Can multiple applications share one DuckDB database?

Not for writing. One process holds the database read-write; others may attach read-only and will not see later writes. Shared multi-writer access needs a different database or a table format with a catalogue.

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.

DuckDB: Is it a replacement for a data warehouse?

For single-node analytical workloads up to a few hundred gigabytes it very often is. It is not a replacement when many concurrent users need a shared, governed, always-on service.

Caddy: Caddy or Nginx?

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

DuckDB: Do I have to load data into it?

No. It queries Parquet, CSV, JSON and Arrow in place, including on object storage. Its own storage format is optional and mainly useful when you want indexes, constraints and faster repeated access.

DuckDB: What is MotherDuck's relationship to it?

MotherDuck is a separate company offering a managed and hybrid service built on the DuckDB engine. DuckDB itself remains MIT-licensed and independent of it, with the IP held by the DuckDB Foundation.

DuckDB: Is it suitable for OLTP?

No. It is designed for analytical scans. For transactional workloads with frequent small writes, SQLite or Postgres is the right tool.

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