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Education · head to head

Anki vs Seldon

Anki logo

Anki

Education

Free open source spaced repetition flashcard app, free everywhere except iOS where it is a paid one-time purchase

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: Anki the interface is functional rather than polished, and new users often find the initial setup, deck creation and add-on ecosystem confusing compared with a guided app like Memrise.; 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: Anki covers Spaced repetition scheduling, Seldon covers Kubernetes custom resources.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Anki and Seldon actually diverge.

Attributes where Anki and Seldon differ
AttributeAnkiSeldon
Pricing modelOpen source, no licence fee except a paid iOS appfreemium
PlatformsWindows, Mac, Linux, iOS, Android, WebLinux
CategoryEducationMachine 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 Anki

  • Spaced repetition scheduling
  • Cross-platform sync
  • Shared deck library
  • Custom card types
  • Add-ons
  • Open file format

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.

Anki

  • A medical student using a large shared deck to memorise anatomy or pharmacology facts on a fixed exam timelinenot Seldon
  • A language learner building custom vocabulary decks with audio and images tailored to their own study materialnot Seldon
  • A self-directed learner who wants full control over the scheduling algorithm and does not want a subscriptionnot Seldon
  • An iPhone-only user deciding whether the one-time AnkiMobile price is worth it versus using the free web interface insteadnot Seldon

Seldon

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

Where each one falls short

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

Anki

  • The interface is functional rather than polished, and new users often find the initial setup, deck creation and add-on ecosystem confusing compared with a guided app like Memrise.
  • iOS users pay a one-time fee of around $24.99 to $29.99 for AnkiMobile while every other platform is free, which is an unusual asymmetry that surprises new users comparing app store prices before they understand it funds development.
  • Anki has no content of its own; a new user gets an empty deck and either has to build cards manually or trust the quality of a community-shared deck of unknown accuracy.
  • The default scheduling algorithm requires understanding concepts like ease factor and interval to tune effectively, and default settings are not optimal for every subject or workload.
  • Shared decks, especially large medical school decks, can carry factual errors or become outdated, and there is no editorial review process verifying their accuracy.

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

Anki

Free
  • AnkiFree
    • Desktop apps for Windows, Mac and Linux are free and open source
    • AnkiDroid on Android is free and open source, built by a separate volunteer team
    • AnkiMobile on iOS is a one-time purchase, commonly $24.99 to $29.99, funding development

Seldon

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

Which should you pick?

Choose Anki if

  • You need spaced repetition scheduling.
  • You want to start without paying.
  • You work on Windows, Mac, Linux, iOS, Android, Web.
  • You also want cross-platform sync.
Anki 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 Anki or Seldon better?
Neither clearly leads. Anki 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, Anki or Seldon?
Anki starts at Free and Seldon at Free.
Does Anki or Seldon run on more platforms?
Anki runs on Windows, Mac, Linux, iOS, Android, Web. Seldon runs on Linux.
Can I use Anki for free?
Both have a free tier, so you can try either at no cost before committing.
What is Anki best used for?
Anki is most often used for a medical student using a large shared deck to memorise anatomy or pharmacology facts on a fixed exam timeline, a language learner building custom vocabulary decks with audio and images tailored to their own study material, a self-directed learner who wants full control over the scheduling algorithm and does not want a subscription, an iphone-only user deciding whether the one-time ankimobile price is worth it versus using the free web interface instead. Of those, a medical student using a large shared deck to memorise anatomy or pharmacology facts on a fixed exam timeline and a language learner building custom vocabulary decks with audio and images tailored to their own study material are not what Seldon is typically brought in for.
What can Anki do that Seldon cannot?
Anki covers Spaced repetition scheduling, Cross-platform sync, Shared deck library, Custom card types. Seldon covers Kubernetes custom resources, Inference graphs, Traffic strategies, Open Inference Protocol.

Answered from the vendors’ own pages

Anki: Why is the iOS app not free when everything else is?

AnkiMobile is a paid one-time purchase, commonly around $24.99 to $29.99, that the developer states directly funds ongoing development of the free desktop apps, AnkiWeb sync and infrastructure used by every platform.

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.

Anki: Is Anki really free on Android?

Yes. AnkiDroid, the Android app, is free and open source, built and maintained by a separate volunteer development team from the desktop project.

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.

Anki: Do I need to pay for sync?

No. AnkiWeb, used to sync decks and review history across devices, is free.

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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