Machine Learning · head to head
Seldon vs Sigstore
Seldon
Machine Learning
Kubernetes model serving whose current version is licensed under the Business Source Licence
- From
- Free
- Rated
- -
Sigstore
Cybersecurity
Free public signing and transparency infrastructure for open source artifacts
- From
- Free
- Rated
- -
The short version
- Each has a real cost: 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.; Sigstore the security model depends on somebody watching the log. The documentation states that compromise of an identity provider or of Fulcio itself is detectable only if third parties monitor the transparency log, the monitoring tool is a community-tier rather than core project, and almost no consumer runs one.
- They diverge on capability: Seldon covers Kubernetes custom resources, Sigstore covers Fulcio.
- Prices and features above were last checked on 31 August 2026.
Where they differ
Only the attributes on which Seldon and Sigstore actually diverge.
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 Seldon
- Kubernetes custom resources
- Inference graphs
- Traffic strategies
- Open Inference Protocol
- Alibi Explain
- Alibi Detect
- Kafka-backed pipelines in v2
- Commercial control plane
Only in Sigstore
- Fulcio
- Rekor
- Keyless signing
- Multi-language clients
- Timestamp authority
- Neutral governance
What people use each for
The jobs each tool is most often brought in to do.
Seldon
- Serving an ensemble or a multi-stage inference path as one versioned deployment rather than as a chain of separate servicesnot Sigstore
- Running genuine production experiments where a share of live traffic goes to a candidate model and the results are comparednot Sigstore
- Regulated environments needing explanations and drift monitoring attached to the served model rather than bolted on laternot Sigstore
- Organisations with an established Kubernetes platform team who want serving expressed as manifests under existing deployment controlsnot Sigstore
Sigstore
- Open source projects signing releases without running a certificate authoritynot Seldon
- Organisations meeting a signed-artifact requirement without buying a signing productnot Seldon
- Publishing provenance that a consumer can verify independently of younot Seldon
- Self-hosting the same components where a public log is unacceptablenot Seldon
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
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.
Sigstore
- The security model depends on somebody watching the log. The documentation states that compromise of an identity provider or of Fulcio itself is detectable only if third parties monitor the transparency log, the monitoring tool is a community-tier rather than core project, and almost no consumer runs one.
- It is a 99.5 percent objective with no service level agreement, which permits several hours of downtime a month and offers no remedy. A pipeline that signs on every build has taken a hard dependency on a free service with no contract behind it.
- Log scale is a live engineering problem rather than a theoretical one. The active shard holds billions of entries, the log has already been sharded twice, and sharding version 1 requires stopping traffic, which is why a replacement was built.
- Ten-minute certificates make trust depend on log availability. Verifying an older signature relies on the log entry proving it was made inside that window, so a lost or unreachable entry can render a valid artifact unverifiable.
- Migration debt is substantial and ongoing. Version 2 of the log is generally available but not the public default, the signing client has an announced breaking release ahead, some official clients lag the new log format, and a post-quantum migration is named as the next break after that.
Pricing, plan by plan
Seldon
Free- Seldon CoreFree
- Open source
- Kubernetes deployment
- Model serving
- Seldon DeployFree
- Enterprise features
- GUI
- Monitoring
Sigstore
Free- Public good instanceFree
- Free to everyone with no contract
- 99.5 percent availability objective, not an agreement
- 100KB cap per attestation upload
- Self-hostedFree
- Apache-2.0
- Run your own Fulcio and Rekor
- Rekor v2 available for self-hosters
Which should you pick?
Choose Seldon if
- You need kubernetes custom resources.
- You want to start without paying.
- You work on Linux.
- You also want inference graphs.
Choose Sigstore if
- You need fulcio.
- You want to start without paying.
- You work on Web, Linux, macOS, Windows, Self-hosted.
- You also want rekor.
Questions people ask
- Is Seldon or Sigstore better?
- Neither clearly leads. Seldon starts at Free and Sigstore at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Seldon or Sigstore?
- Seldon starts at Free and Sigstore at Free.
- Does Seldon or Sigstore run on more platforms?
- Seldon runs on Linux. Sigstore runs on Web, Linux, macOS, Windows, Self-hosted.
- Can I use Seldon for free?
- Both have a free tier, so you can try either at no cost before committing.
- What is Seldon best used for?
- Seldon is most often used for serving an ensemble or a multi-stage inference path as one versioned deployment rather than as a chain of separate services, running genuine production experiments where a share of live traffic goes to a candidate model and the results are compared, regulated environments needing explanations and drift monitoring attached to the served model rather than bolted on later, organisations with an established kubernetes platform team who want serving expressed as manifests under existing deployment controls. Of those, serving an ensemble or a multi-stage inference path as one versioned deployment rather than as a chain of separate services and running genuine production experiments where a share of live traffic goes to a candidate model and the results are compared are not what Sigstore is typically brought in for.
- What can Seldon do that Sigstore cannot?
- Seldon covers Kubernetes custom resources, Inference graphs, Traffic strategies, Open Inference Protocol. Sigstore covers Fulcio, Rekor, Keyless signing, Multi-language clients.
Answered from the vendors’ own pages
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.
Sigstore: Is the public instance really free?
Yes, with no contract and no paid tier. That is also the weakness: a 99.5 percent objective with no agreement, no remedy and support through Slack.
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.
Sigstore: Has the public log moved to Rekor v2?
No. Version 2 reached general availability in October 2025 and self-hosters can use it, but the public instance still defaults to version 1 and the project has said it will for the foreseeable future.
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.
Sigstore: Does Sigstore make my dependencies safe?
No, and this is a category error worth avoiding. It tells you who published something. It has no knowledge of what the artifact contains or whether it is vulnerable.
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.
Sigstore: What are the rate limits?
Not published. Only the 100KB cap per attestation upload is documented, so do not design a high-volume pipeline around assumed throughput.
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.
Sigstore: Should we self-host it?
If a public record of every signature is unacceptable, or if a free service with no agreement cannot sit in your build path, then yes. Otherwise the public instance is what most projects use.
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