v1.38.0

April 7, 2026

🌟 New features

HTTP/JSON to gRPC Proxy: You can now use DelegatingHttpJsonTranscodingService to accept HTTP/JSON traffic and forward it as gRPC to any HttpService delegate, without needing a local gRPC service implementation. #6669

WebClient client = ...;
HttpService delegate = (ctx, req) -> client.execute(req);
DelegatingHttpJsonTranscodingService service =
    DelegatingHttpJsonTranscodingService
        .builder(delegate)
        .serviceDescriptors(MyServiceGrpc.getServiceDescriptor()) // 👈👈👈
        .build();

KubernetesEndpointGroup POD Mode: KubernetesEndpointGroup now supports POD mode for intra-cluster communication, connecting directly to podIP:containerPort for true client-side load balancing. #6600 #6661

KubernetesEndpointGroup endpointGroup =
    KubernetesEndpointGroup.builder(kubernetesClient)
                           .namespace("my-namespace")
                           .serviceName("my-service")
                           .mode(KubernetesEndpointMode.POD) // 👈👈👈
                           .build();

Envoy gRPC HTTP/1.1 Bridge: GrpcService now supports the Envoy gRPC HTTP/1.1 bridge specification via GrpcServiceBuilder.enableEnvoyHttp1Bridge(). When enabled, unary gRPC responses over HTTP/1.1 merge grpc-status and trailers into response headers, improving compatibility with legacy proxy servers. This applies only to unary methods; streaming methods are unaffected. #6664 #6689
```
GrpcService.builder()
           .addService(myGrpcService)
           .enableEnvoyHttp1Bridge(true) // 👈👈👈
           .build();
```
Kubernetes Node IP Extractor: KubernetesEndpointGroup can now extract a Node IP from labels or annotations via KubernetesEndpointGroupBuilder.nodeIpExtractor(), useful for CNI-managed environments like Calico. #6660
Additional BuiltInProperty Entries: BuiltInProperty now includes 15 new properties for timing, content preview, and protocol information, aligning it with AccessLogComponent. #4403 #6683
- Timing: req.start_time_millis, req.duration_millis, res.duration_millis, total_duration_millis, etc.
- Content preview: req.content_preview, res.content_preview
- Protocol: serialization.format, session.protocol, host
Token Preloading: You can now set AsyncLoaderBuilder.preload() to eagerly fetch tokens at build time, reducing first-request latency. OAuth2AuthorizationGrantBuilder and AthenzClientBuilder also support this option. #6688

Standalone Athenz Token Client: You can now use AthenzTokenClient to fetch Athenz tokens independently of Armeria's HTTP decorator pipeline. #6431 #6691

AthenzTokenClient tokenClient =
    AthenzTokenClient.builder(ztsBaseClient)
                     .domainName("my-domain")
                     .roleNames("my-role")
                     .build();
tokenClient.getToken().thenAccept(token -> { // 👈👈👈
    // Use the token with any HTTP client.
});

Athenz Metrics: You can now monitor Athenz policy load success/failure rates and token cache hit/miss metrics via a configurable MeterRegistry on AthenzAuthorizer and AthenzService builders. #6690
xDS SDS Integration: xDS now supports transport-socket TLS with SAN and certificate pin verification for upstream connections, and SDS integration with XdsPreprocessor. #6628

📈 Improvements

StreamDecoderFactory now supports flexible content-encoding matching via StreamDecoderFactory.matchesEncodingHeaderValue(). This fixes interoperability with frameworks like Netty that return snappy instead of x-snappy-framed. #6681 #6684

You can now bind a VirtualHost to a random (ephemeral) port using a ServerPort object, useful for CI environments where port conflicts must be avoided. #6410 #6603

ServerPort port1 = new ServerPort(0, SessionProtocol.HTTP);
ServerPort port2 = new ServerPort(0, SessionProtocol.HTTP);
Server server = Server.builder()
    .port(port1)
    .virtualHost(port1) // 👈👈👈
        .service("/foo", (ctx, req) -> HttpResponse.of("foo"))
    .and()
    .port(port2)
    .virtualHost(port2) // 👈👈👈
        .service("/bar", (ctx, req) -> HttpResponse.of("bar"))
    .and()
    .build();

DocService now correctly generates JSON Schema with oneOf and discriminator fields for types annotated with Jackson's @JsonTypeInfo and @JsonSubTypes. #6370

🛠️ Bug fixes

RequestContextExportingAppender no longer throws a NullPointerException during RequestContextStorage initialization in Logback 1.5.21 and later. #6662