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Preact vs Seldon

Preact logo

Preact

Web Development

3kB alternative to React with the same modern API

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: Preact compatibility through preact/compat is good but not total, and some React libraries break in ways that are hard to diagnose; 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: Preact covers 3kB runtime, Seldon covers Kubernetes custom resources.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Preact and Seldon actually diverge.

Attributes where Preact and Seldon differ
AttributePreactSeldon
Pricing modelOpen source, no licence feefreemium
PlatformsWebLinux
CategoryWeb DevelopmentMachine Learning
FoundedUnknown2014

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 Preact

  • 3kB runtime
  • preact/compat
  • Same modern API
  • Fast rendering

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.

Preact

  • Embedded widgets that load inside someone else’s page and must stay smallnot Seldon
  • Marketing and content sites where JavaScript payload affects Core Web Vitalsnot Seldon
  • Applications targeting low-bandwidth or low-powered devicesnot Seldon

Seldon

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

Where each one falls short

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

Preact

  • Compatibility through preact/compat is good but not total, and some React libraries break in ways that are hard to diagnose
  • Behavioural differences from React exist in edge cases, particularly around event handling
  • A much smaller community, so unusual problems have fewer existing answers than React

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

Preact

Free
  • PreactFree
    • Full library
    • Commercial use permitted
    • No usage limits

Seldon

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

Which should you pick?

Choose Preact if

  • You need 3kb runtime.
  • You want to start without paying.
  • You also want preact/compat.
Preact 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 Preact or Seldon better?
Neither clearly leads. Preact 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, Preact or Seldon?
Preact starts at Free and Seldon at Free.
Does Preact or Seldon run on more platforms?
Preact runs on Web. Seldon runs on Linux.
Can I use Preact for free?
Both have a free tier, so you can try either at no cost before committing.
What is Preact best used for?
Preact is most often used for embedded widgets that load inside someone else’s page and must stay small, marketing and content sites where javascript payload affects core web vitals, applications targeting low-bandwidth or low-powered devices. Of those, embedded widgets that load inside someone else’s page and must stay small and marketing and content sites where javascript payload affects core web vitals are not what Seldon is typically brought in for.
What can Preact do that Seldon cannot?
Preact covers 3kB runtime, preact/compat, Same modern API, Fast rendering. Seldon covers Kubernetes custom resources, Inference graphs, Traffic strategies, Open Inference Protocol.

Answered from the vendors’ own pages

Preact: Is Preact free?

Yes, open source under the MIT licence.

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.

Preact: Can I use React libraries with Preact?

Most, through the preact/compat layer. Compatibility is good but not complete, so libraries relying on React internals can break.

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.

Preact: Why choose Preact over React?

Bundle size, almost always. If payload is not a binding constraint, React’s ecosystem is usually the better trade.

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.

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.

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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