One Java API for every cloud

halyx:
  providers:
    cloud: { type: aws, region: eu-west-2 }   # or azure, gcp
  blob-stores:
    invoices: { bucket: acme-invoices }
  topics:
    order-events: { name: orders }
  subscriptions:
    billing: { name: orders-billing }

@Component
class Billing {
    @HalyxListener("billing")
    void onOrder(String json) {   // return = ack, throw = retry
        bill(json);
    }
}

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"); // S3
    Publisher events = halyx.provider("gcp").publisher("order-events");   // Pub/Sub

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

    try (Blob blob = invoices.get(BlobKey.of("2026/41.pdf"))) {
        blob.content().transferTo(out);
    } catch (NotFoundException e) {
        // the same exception on S3, Azure Blob Storage and Cloud Storage
    }
}