Built with domain experts in mind

Simply express the decision logic

Nussknacker allows domain experts to define decision algorithms in the most natural way. Instead of sets of interdependent rules or SQL statements, they work with easy-to-follow and understand flow diagrams.

For logical conditions, calculations and other expressions that complement the diagrams there's a powerful expression language. It's based on SpEL (Spring Expression Language) and supports advanced querying and manipulation of data.

To make writing those expressions easier, Nussknacker integrates with various metadata sources, to automatically discover the structure of input and output data. This information is utilized by advanced contextual expression suggestions, autocompletion and validation mechanism.

Enrich the data, enhance the decisions

The data in the event that triggers a decision is often not enough to make the decision. Nussknacker can enrich it with information from various sources: private and public APIs, databases and machine learning models.

That doesn't mean domain experts have to worry about addresses, credentials etc. They can focus on business logic because Nussknacker hides all of the technical details under the hood. And, no matter the enrichment source, Nussknacker, as always, helps users by using available metadata to provide automatic suggestions and validation.

Test before you deploy, monitor the results

Nussknacker wants users to feel safe and confident about the changes they make. That's why it provides different testing and debugging mechanisms.

You can test on data recorded from a live environment or provide your own test cases. You can also monitor execution paths of a running scenario for debugging purposes.

And if you need more technical details, Nussknacker makes numerous metrics available on a Grafana® dashboard out of the box. You can easily check scenario throughput, statistics about decisions made, errors and more.

Deploy anytime, all the time

Nussknacker encourages iterative improvements of decision algorithms. Once created or modified, decision scenarios are deployed for execution with a click of a button. And you can always revert to an older version or compare different versions of a scenario, thanks to full version history.

Built with flexibility in mind

Fits your architecture


From an architectural point of view, Nussknacker is a decision service. So we had to make it fit various event driven architectures, streaming and request-response.

In streaming use cases Nussknacker can connect directly to any Kafka-compatible streaming platform. Or, if you don't want to use Kafka, Nussknacker also has an HTTP interface with a subscription mechanism that can receive input streams and send output streams over HTTP.


For synchronous, request-response use cases Nussknacker creates an OpenAPI service for every decision scenario.

And whatever the source of input data, Nussknacker can enrich it with information from:

  • any REST endpoint with an OpenAPI definition
  • any database available via JDBC
  • by directly inferring ML models, either JPMML encoded or exported with H2O Mojo/Pojo or by calling models exposed as OpenAPI endpoints
As straightforward or as sophisticated as you need

There are two engines available in Nussknacker, that focus on different needs:

Lightweight Kubernetes-native engine if you want to deploy Nussknacker simply as just another service on your platform

Flink engine if your business logic requires data aggregation or other ways of stateful stream processing


No matter which engine you choose, you always get enterprise grade performance: horizontal scalability, high availability, high throughput and low latency.

Fits your domain

Nussknacker adapts to any domain. It uses names specific to your domain based on a schema registry, OpenAPI definitions or SQL tables metadata and can be further customised with various configuration options.

And when customisation is not enough, Nussknacker can be extended to fit a specific use case. You can use our enterprise components or build your own, taking advantage of Nussknacker's extensions API.

Manage it yourself or let us do it

Nussknacker is open source. You can run it anywhere and any way you want. You only need Kubernetes or Flink (for stateful stream processing). And if you need support, we've got you covered.

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But if you don't want to manage Nussknacker yourself, use our fully managed Nussknacker Cloud. You can connect to it over HTTP or set it up to work with your own Kafka-compatible service in the cloud, like Confluent Cloud, Aiven or on premises.

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Next steps

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