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Databases · head to head

PostgreSQL vs Seldon

PostgreSQL logo

PostgreSQL

Databases

The world's most advanced open source relational database

From
Free
Rated
-
Full reviewWebsite
Seldon logo

Seldon

Machine Learning

Kubernetes model serving whose current version is licensed under the Business Source Licence

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: PostgreSQL requires manual scaling across multiple machines for very large deployments; Seldon seldon Core v2 is under the Business Source Licence rather than Apache 2.0, so production use requires a commercial agreement, and a team that evaluated it believing it was open source discovers the licence is the blocker exactly when the project is ready to ship.
  • They diverge on capability: PostgreSQL covers ACID Compliance, Seldon covers Kubernetes custom resources.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which PostgreSQL and Seldon actually diverge.

Attributes where PostgreSQL and Seldon differ
AttributePostgreSQLSeldon
Pricing modelUnknownfreemium
PlatformsLinux, Windows, macOS, BSD, UnixLinux
CategoryDatabasesMachine Learning
Founded19962014

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 PostgreSQL

  • ACID Compliance
  • JSON/JSONB Support
  • Full-text Search
  • Extensibility
  • Advanced Indexing
  • Partitioning
  • Replication
  • pgAdmin

Only in Seldon

  • Kubernetes custom resources
  • Inference graphs
  • Traffic strategies
  • Open Inference Protocol
  • Alibi Explain
  • Alibi Detect
  • Kafka-backed pipelines in v2
  • Commercial control plane

What people use each for

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

PostgreSQL

  • Transaction processingnot Seldon
  • Data storagenot Seldon
  • Application backendnot Seldon
  • Reportingnot Seldon
  • Data analyticsnot Seldon

Seldon

  • Serving an ensemble or a multi-stage inference path as one versioned deployment rather than as a chain of separate servicesnot PostgreSQL
  • Running genuine production experiments where a share of live traffic goes to a candidate model and the results are comparednot PostgreSQL
  • Regulated environments needing explanations and drift monitoring attached to the served model rather than bolted on laternot PostgreSQL
  • Organisations with an established Kubernetes platform team who want serving expressed as manifests under existing deployment controlsnot PostgreSQL

Where each one falls short

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

PostgreSQL

  • Requires manual scaling across multiple machines for very large deployments
  • Performance tuning requires deep knowledge of database internals
  • No built-in graphical admin interface; command-line tools are primary method

Seldon

  • Seldon Core v2 is under the Business Source Licence rather than Apache 2.0, so production use requires a commercial agreement, and a team that evaluated it believing it was open source discovers the licence is the blocker exactly when the project is ready to ship.
  • Core v1 remains Apache 2.0 but is in maintenance, so taking the free route means running software that receives no new development while the architecture it belongs to moves on without it.
  • Version 2 is a different system rather than a newer release, with different custom resources, a scheduler component and a Kafka-based pipeline model, so migrating from v1 is a re-implementation of every deployment manifest rather than an upgrade.
  • Kafka is a dependency for v2 pipelines, so an organisation that does not already operate it takes on a distributed log with its own storage, retention, rebalancing and failure modes purely in order to serve models.
  • Everything assumes Kubernetes fluency and the failure modes are Kubernetes failure modes, custom resource version mismatches, an operator that will not reconcile, admission webhooks and resource limits terminating an inference pod mid-request, so it needs a platform engineer rather than a data scientist.

Pricing, plan by plan

PostgreSQL

Free

No published plan breakdown. See the PostgreSQL review.

Seldon

Free
  • Seldon CoreFree
    • Open source
    • Kubernetes deployment
    • Model serving
  • Seldon DeployFree
    • Enterprise features
    • GUI
    • Monitoring

Which should you pick?

Choose PostgreSQL if

  • You need acid compliance.
  • You want to start without paying.
  • You work on Linux, Windows, macOS, BSD, Unix.
  • You also want json/jsonb support.
PostgreSQL review

Choose Seldon if

  • You need kubernetes custom resources.
  • You want to start without paying.
  • You work on Linux.
  • You also want inference graphs.
Seldon review

Questions people ask

Is PostgreSQL or Seldon better?
Neither clearly leads. PostgreSQL starts at Free and Seldon at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, PostgreSQL or Seldon?
PostgreSQL starts at Free and Seldon at Free.
Does PostgreSQL or Seldon run on more platforms?
PostgreSQL runs on Linux, Windows, macOS, BSD, Unix. Seldon runs on Linux.
Can I use PostgreSQL for free?
Both have a free tier, so you can try either at no cost before committing.
What is PostgreSQL best used for?
PostgreSQL is most often used for transaction processing, data storage, application backend, reporting. Of those, transaction processing and data storage are not what Seldon is typically brought in for.
What can PostgreSQL do that Seldon cannot?
PostgreSQL covers ACID Compliance, JSON/JSONB Support, Full-text Search, Extensibility. Seldon covers Kubernetes custom resources, Inference graphs, Traffic strategies, Open Inference Protocol.

Answered from the vendors’ own pages

PostgreSQL: Is PostgreSQL completely free?

Yes. PostgreSQL is completely free and open source with no licensing fees or restrictions on use.

Source
Seldon: Is Seldon open source?

Partly, and this is the thing to check before you build on it. Core v1 is Apache 2.0 but in maintenance. Core v2 was moved to the Business Source Licence in 2024, which allows evaluation but not unlicensed production use. Verify the current licence of each component you intend to run, including MLServer and the Alibi libraries.

PostgreSQL: What platforms does PostgreSQL run on?

PostgreSQL runs on all major operating systems including Linux, Windows, macOS, BSD, and commercial Unix variants, and has been proven highly scalable managing terabytes to petabytes of data.

Source
Seldon: What is the difference between v1 and v2?

Architecture, not just version number. v2 introduces a scheduler, a different set of custom resources and Kafka-backed pipelines. Manifests, mental model and operations all change, so treat a move as a project.

PostgreSQL: What procedural languages are supported?

PostgreSQL supports stored functions and procedures in multiple languages including PL/pgSQL, Perl, Python, Tcl, Java, JavaScript, R, and Rust.

Source
Seldon: Do I need Kubernetes?

Yes. It is a Kubernetes-native system and there is no meaningful deployment without a cluster and someone competent to run it.

PostgreSQL: What is ACID compliance in PostgreSQL?

PostgreSQL has been ACID-compliant since 2001, ensuring data integrity through atomicity, consistency, isolation, and durability guarantees for all transactions.

Source
Seldon: What is MLServer?

Seldon's Python inference server implementing the Open Inference Protocol, usable inside Seldon deployments or on its own. Check its current licence alongside Core's, since the company has moved projects onto the Business Source Licence.

PostgreSQL: Does PostgreSQL support JSON data?

Yes. PostgreSQL supports JSON and JSONB data types for storing and querying JSON documents, along with XML and other document formats.

Source
Seldon: Do I have to run Kafka?

For v2 pipelines, yes. If you only need single models served, that dependency is a large amount of infrastructure for the benefit, and a simpler serving layer may be the better answer.

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