Alginte 0.13.0 Beta

Released 2026-09-18.

Alginte is in beta (0.x): configuration keys, the topology export format, and APIs may change between releases; breaking changes are called out in release notes with migration guidance. 0.13.0 has one behaviour change that can stop a stream that ran before, on Protobuf topics only; it is the first item under Behaviour changes below, with what to check.

0.13.0 is the release for starting in a sandbox: a stack of your own that you are free to break, your schemas and a sample of your records in it, a stream designed and proved there, and carried to your cluster as a file. Each item links to its documentation; the argument for working this way is the post A Kafka Streams topology starts in a sandbox, not on your cluster.

New

• The playground is where to start, whether or not you have a cluster: the whole product with its own broker, isolated on your machine, and docker compose down undoes everything.
• Bring your schemas and your data: two folders beside the compose file, registered and produced at every up, so your subjects and a sample of your records survive the reset. Templates are in the community repository.
• From the playground to your cluster, a guide: design, prove, download, upload, and what is different at the border.
• A design carries its logic, not its cluster: an upload leaves out bootstrap.servers, the registry URL and the security settings and names which, and the deploy gate refuses a source whose subject this registry does not have, naming the node.
• Sandbox mode and the stream tools: in the playground the MCP endpoint also offers validate_topology, deploy_topology, evaluate_expression, stop_stream and delete_stream, so an agent can work the builder the way a person does. Refusals come back as data. Off everywhere else.
• A warning on a JSON Schema name the subject does not declare: the one format where a misspelt field is a quiet null at runtime now gets a warning on the literal while you type, with the declared names and the closest one.

Behaviour changes

• A missing field follows one rule: a name the schema can reject fails at access, and a Map answers null. On Protobuf, get('x') with a name the schema does not know now fails with Not a valid schema field: x, as it always did on Avro; before 0.13.0 it answered null. A Protobuf topology that names such a field was dropping records silently and will now fail at its first record. To check before upgrading, open the design in the builder: the editor reports the same failure on the expression. JSON Schema and JSON are unchanged.
• describe_stream and list_streams answer compactly over MCP: state, flags, the topology description and the failure. The metrics and the design come on request, with includeMetrics and includeDesign; a client that read them from the default answer has to ask for them.

Fixes

• The read-only MCP tools advertised themselves as destructive as well as read-only, a framework default; a client that confirms destructive calls could prompt on a plain listing. They now say they are not.

For operators

• alginte.sandbox.enabled switches the stream tools on. The playground sets it. Never set it on an instance that runs against a shared cluster.
• The playground's images are variables with their defaults in the compose file: ALGINTE_IMAGE pins a release, beside the existing ALGINTE_PORT.

Get it

docker pull alginte/alginte:latest

Or the JAR (SHA-256), run with Java 25. Full install guide in the documentation — or start in the playground: one command, no Kafka needed.