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Databases · head to head

DuckDB vs OpenVPN

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
OpenVPN logo

OpenVPN

Networking

Open source VPN protocol with a commercial Access Server product priced per simultaneous connection

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: 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.; OpenVPN open source OpenVPN, while free, requires real technical skill to configure, secure and maintain without the Access Server admin layer
  • They diverge on capability: DuckDB covers In-process execution, OpenVPN covers Open source core.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which DuckDB and OpenVPN actually diverge.

Attributes where DuckDB and OpenVPN differ
AttributeDuckDBOpenVPN
Pricing modelopen-sourceOpen source core is free; Access Server billed per simultaneous connection
PlatformsLinux, macOS, Windows, WebAssemblyLinux, Windows, macOS, iOS, Android
CategoryDatabasesNetworking
Founded2019Unknown

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 DuckDB

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

Only in OpenVPN

  • Open source core
  • Access Server admin UI
  • Per-connection licensing
  • Free tier
  • Cross-platform clients

What people use each for

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

DuckDB

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

OpenVPN

  • A technical team wanting a fully free, self-configured VPN server using the open source protocol without any vendor relationshipnot DuckDB
  • A small business wanting a supported, easier-to-administer VPN server, willing to pay per concurrent connection rather than per employeenot DuckDB
  • An organisation with more staff than typical concurrent VPN usage, since Access Server bills only active simultaneous connections, not total accountsnot DuckDB
  • An IoT or large-scale deployment needing custom Enterprise pricing above 2,000 connectionsnot DuckDB

Where each one falls short

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

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.

OpenVPN

  • Open source OpenVPN, while free, requires real technical skill to configure, secure and maintain without the Access Server admin layer
  • Per-connection billing on Access Server means usage spikes, such as an all-hands remote day, can push simultaneous connections over a licensed limit and block new connections until usage drops or the plan is upgraded
  • OpenVPN's traditional hub-and-spoke architecture routes traffic through a central server, unlike mesh VPN tools like Tailscale or NetBird that establish direct peer-to-peer connections where possible, which can add latency
  • Client configuration and certificate management for the open source version is more manual and error-prone than newer VPN tools with zero-config onboarding
  • Access Server pricing above the Growth tier reverts to custom Enterprise quoting, so very large deployments lose the pricing transparency of the lower tiers
  • The protocol's throughput is generally lower than newer kernel-integrated protocols like WireGuard under equivalent conditions, which matters for high-bandwidth use cases

Pricing, plan by plan

DuckDB

Free

No published plan breakdown. See the DuckDB review.

OpenVPN

Free
  • Access Server FreeFree
    • Up to 2 simultaneous connections
    • All features included
  • Access Server Growth$7/month
    • Per simultaneous connection beyond the free tier
    • Annual billing
  • Access Server Enterprise/IoT$undefined/month
    • Custom pricing for 2,000+ connections

Which should you pick?

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

Choose OpenVPN if

  • You need open source core.
  • You want to start without paying.
  • You work on Linux, Windows, macOS, iOS, Android.
  • You also want access server admin ui.
OpenVPN review

Questions people ask

Is DuckDB or OpenVPN better?
Neither clearly leads. DuckDB starts at Free and OpenVPN at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, DuckDB or OpenVPN?
DuckDB starts at Free and OpenVPN at Free.
Does DuckDB or OpenVPN run on more platforms?
DuckDB runs on Linux, macOS, Windows, WebAssembly. OpenVPN runs on Linux, Windows, macOS, iOS, Android.
Can I use DuckDB for free?
Both have a free tier, so you can try either at no cost before committing.
What is DuckDB best used for?
DuckDB is most often used for transformation steps in a data pipeline that would otherwise need spark, replaced by sql over parquet in a single process, analytical queries embedded in an application or a dashboard where shipping a database server alongside it is not acceptable, local exploration of files that are too large for a pandas dataframe but far too small to justify a warehouse, continuous integration and testing of analytical sql, where a real engine can run in the test process without provisioning anything. Of those, transformation steps in a data pipeline that would otherwise need spark, replaced by sql over parquet in a single process and analytical queries embedded in an application or a dashboard where shipping a database server alongside it is not acceptable are not what OpenVPN is typically brought in for.
What can DuckDB do that OpenVPN cannot?
DuckDB covers In-process execution, Vectorised columnar engine, Direct file querying, Zero dependencies. OpenVPN covers Open source core, Access Server admin UI, Per-connection licensing, Free tier.

Answered from the vendors’ own pages

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.

OpenVPN: Is OpenVPN free?

The open source protocol and software are free under the GPL; Access Server, the commercial packaged product, charges per simultaneous connection beyond a free 2-connection tier.

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.

OpenVPN: What counts as a connection for billing purposes?

A simultaneously active connected device, not a registered user account or total device count; unlimited accounts and devices can be created but only the licensed number can be connected at once.

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.

OpenVPN: How does OpenVPN compare with WireGuard-based tools like Tailscale?

OpenVPN uses a traditional hub-and-spoke VPN architecture rather than the mesh, peer-to-peer approach used by newer tools like Tailscale or NetBird.

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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