Halyx

One Java API for AWS, Azure and Google Cloud. Halyx gives Java 21 microservices one consistent way to use cloud services (object storage, NoSQL, messaging, streams, SQL, caches, parameters and secrets) on AWS, Azure and Google Cloud. The services keep their own SDKs and strengths; your code stops depending on them. Get started API guide Spring Boot

Write it once, run it on any cloud#

Java

try (Halyx halyx = Halyx.builder()
        .register("aws", ProviderConfig.of("aws").region("eu-west-2"))
        .register("gcp", ProviderConfig.of("gcp").property(GcpProperties.PROJECT_ID, "acme-prod"))
        .build()) {

    BlobStore invoices = halyx.provider("aws").blobStore("acme-invoices");     // Amazon S3
    Publisher events = halyx.provider("gcp").publisher("order-events");       // Google Cloud Pub/Sub

    invoices.put(BlobKey.of("2026/42.pdf"), BlobContent.ofFile(pdf));
    events.publish(OutgoingMessage.builder(json).attribute("type", "invoiced").build());
}

Moving the invoices to Azure Blob Storage is a change of provider name, not a rewrite. Errors, retries, conditional writes, versions and expiry behave the same on every cloud, and a shared conformance kit checks that for every provider, against emulators on every build and against the real clouds.

Services#

Service	Halyx API	AWS	Azure	Google Cloud	Also
Object storage	`BlobStore`	Amazon S3	Azure Blob Storage	Cloud Storage	in-memory
NoSQL documents	`DocumentStore`	DynamoDB	Cosmos DB for NoSQL	Firestore	in-memory
Messaging	`Publisher`, `Subscription`	SNS, SQS	Service Bus	Pub/Sub	in-memory
Events	`CloudEvent`, `EventPublisher`	EventBridge	Event Grid namespaces	Eventarc Advanced	in-memory
Streams	`StreamProducer`, `StreamConsumer`	MSK	Event Hubs (Kafka endpoint)	Managed Service for Apache Kafka	any Kafka cluster, in-memory
Functions	`FunctionInvoker`	Lambda	Azure Functions	Cloud Run functions	in-memory
SQL databases	`Database` (a JDBC `DataSource`)	RDS, Aurora	Azure Database for PostgreSQL and MySQL, Azure SQL	Cloud SQL	any PostgreSQL, MySQL or SQL Server
Caches	`Cache`	ElastiCache	Azure Cache for Redis, Azure Managed Redis	Memorystore	any Redis or Valkey server, in-memory
Parameters and secrets	`ParameterStore`	SSM Parameter Store, Secrets Manager	App Configuration, Key Vault	Parameter Manager, Secret Manager	HashiCorp Vault, in-memory

Why teams use it#

Portable code: The same API, error types and semantics on every cloud. Services move between providers by configuration.
Several clouds in one service: Each cloud is a named provider in one Halyx object, so one microservice can read from S3, publish to Pub/Sub and cache in Azure without a second SDK or a second set of error handling.
No lowest common denominator: Differences are declared as capabilities rather than hidden, and unwrap hands you the native SDK client for anything provider-specific.
Passwordless by default: Databases, caches and streams log in with the cloud's identity (AWS IAM, Microsoft Entra ID, Google IAM), with tokens refreshed before they expire.
Production behaviour built in: Parallel transfers, batching, checksums, presigned URLs, claim checks, listener concurrency, fail-open caches, and observability through Micrometer.
Spring Boot ready: A starter for Boot 3.5 and 4: beans from halyx.* properties, @HalyxListener, health checks, metrics, tracing and spring.config.import for parameters and secrets.

Where to go next#

Getting started: add the dependencies and make your first calls.
API guide: every service, with examples, error handling and native-client access.
Provider configuration: credentials, regions, endpoints and every provider setting.
Spring Boot: the starter, its properties, beans and integrations.
Design, build and test: how Halyx is built, tested and benchmarked.
Cloud testing: results of the conformance kits on real AWS, Azure and Google Cloud.
Roadmap: what's done and what's next.