Gateway API 1.4: New Features

By Beka Modebadze (Google), Gateway API Contributors |

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Ready to rock your Kubernetes networking? The Kubernetes SIG Network community presented the General Availability (GA) release of Gateway API (v1.4.0)! Released on October 6, 2025, version 1.4.0 reinforces the path for modern, expressive, and extensible service networking in Kubernetes.

Gateway API v1.4.0 brings three new features to the Standard channel (Gateway API's GA release channel):

  • BackendTLSPolicy for TLS between gateways and backends
  • supportedFeatures in GatewayClass status
  • Named rules for Routes

and introduces three new experimental features:

  • Mesh resource for service mesh configuration
  • Default gateways to ease configuration burden**
  • externalAuth filter for HTTPRoute

Graduations to Standard Channel

Backend TLS policy

Leads: Candace Holman, Norwin Schnyder, Katarzyna Łach

GEP-1897: BackendTLSPolicy

BackendTLSPolicy is a new Gateway API type for specifying the TLS configuration of the connection from the Gateway to backend pod(s). . Prior to the introduction of BackendTLSPolicy, there was no API specification that allowed encrypted traffic on the hop from Gateway to backend.

The BackendTLSPolicy validation configuration requires a hostname. This hostname serves two purposes. It is used as the SNI header when connecting to the backend and for authentication, the certificate presented by the backend must match this hostname, unless subjectAltNames is explicitly specified.

If subjectAltNames (SANs) are specified, the hostname is only used for SNI, and authentication is performed against the SANs instead. If you still need to authenticate against the hostname value in this case, you MUST add it to the subjectAltNames list.

BackendTLSPolicy validation configuration also requires either caCertificateRefs or wellKnownCACertificates. caCertificateRefs refer to one or more (up to 8) PEM-encoded TLS certificate bundles. If there are no specific certificates to use, then depending on your implementation, you may use wellKnownCACertificates, set to "System" to tell the Gateway to use an implementation-specific set of trusted CA Certificates.

In this example, the BackendTLSPolicy is configured to use certificates defined in the auth-cert ConfigMap to connect with a TLS-encrypted upstream connection where pods backing the auth service are expected to serve a valid certificate for auth.example.com. It uses subjectAltNames with a Hostname type, but you may also use a URI type.

apiVersion: gateway.networking.k8s.io/v1
kind: BackendTLSPolicy
metadata:
  name: tls-upstream-auth
spec:
  targetRefs:
  - kind: Service
    name: auth
    group: ""
    sectionName: "https"
  validation:
    caCertificateRefs:
    - group: "" # core API group
      kind: ConfigMap
      name: auth-cert
    subjectAltNames: 
    - type: "Hostname"
      hostname: "auth.example.com"

In this example, the BackendTLSPolicy is configured to use system certificates to connect with a TLS-encrypted backend connection where Pods backing the dev Service are expected to serve a valid certificate for dev.example.com.

apiVersion: gateway.networking.k8s.io/v1
kind: BackendTLSPolicy
metadata:
  name: tls-upstream-dev
spec:
  targetRefs:
  - kind: Service
    name: dev
    group: ""
    sectionName: "btls"
  validation:
    wellKnownCACertificates: "System"
    hostname: dev.example.com

More information on the configuration of TLS in Gateway API can be found in Gateway API - TLS Configuration.

Status information about the features that an implementation supports

Leads: Lior Lieberman, Beka Modebadze

GEP-2162: Supported features in GatewayClass Status

GatewayClass status has a new field, supportedFeatures. This addition allows implementations to declare the set of features they support. This provides a clear way for users and tools to understand the capabilities of a given GatewayClass.

This feature's name for conformance tests (and GatewayClass status reporting) is SupportedFeatures. Implementations must populate the supportedFeatures field in the .status of the GatewayClass before the GatewayClass is accepted, or in the same operation.

Here’s an example of a supportedFeatures published under GatewayClass' .status:

apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
...
status:
  conditions:
  - lastTransitionTime: "2022-11-16T10:33:06Z"
    message: Handled by Foo controller
    observedGeneration: 1
    reason: Accepted
    status: "True"
    type: Accepted
  supportedFeatures:
    - HTTPRoute
    - HTTPRouteHostRewrite
    - HTTPRoutePortRedirect
    - HTTPRouteQueryParamMatching

Graduation of SupportedFeatures to Standard, helped improve the conformance testing process for Gateway API. The conformance test suite will now automatically run tests based on the features populated in the GatewayClass' status. This creates a strong, verifiable link between an implementation's declared capabilities and the test results, making it easier for implementers to run the correct conformance tests and for users to trust the conformance reports.

This means when the SupportedFeatures field is populated in the GatewayClass status there will be no need for additional conformance tests flags like –suported-features, or –exempt or –all-features. It's important to note that Mesh features are an exception to this and can be tested for conformance by using Conformance Profiles, or by manually providing any combination of features related flags until the dedicated resource graduates from the experimental channel.

Named rules for Routes

GEP-995: Adding a new name field to all xRouteRule types (HTTPRouteRule, GRPCRouteRule, etc.)

Leads: Guilherme Cassolato

This enhancement enables route rules to be explicitly identified and referenced across the Gateway API ecosystem. Some of the key use cases include:

  • Status: Allowing status conditions to reference specific rules directly by name.
  • Observability: Making it easier to identify individual rules in logs, traces, and metrics.
  • Policies: Enabling policies (GEP-713) to target specific route rules via the sectionName field in their targetRef[s].
  • Tooling: Simplifying filtering and referencing of route rules in tools such as gwctl, kubectl, and general-purpose utilities like jq and yq.
  • Internal configuration mapping: Facilitating the generation of internal configurations that reference route rules by name within gateway and mesh implementations.

This follows the same well-established pattern already adopted for Gateway listeners, Service ports, Pods (and containers), and many other Kubernetes resources.

While the new name field is optional (so existing resources remain valid), its use is strongly encouraged. Implementations are not expected to assign a default value, but they may enforce constraints such as immutability.

Finally, keep in mind that the name format is validated, and other fields (such as sectionName) may impose additional, indirect constraints.

Experimental channel changes

Enabling external Auth for HTTPRoute

Giving Gateway API the ability to enforce authentication and maybe authorization as well at the Gateway or HTTPRoute level has been a highly requested feature for a long time. (See the GEP-1494 issue for some background.)

This Gateway API release adds an Experimental filter in HTTPRoute that tells the Gateway API implementation to call out to an external service to authenticate (and, optionally, authorize) requests.

This filter is based on the Envoy ext_authz API, and allows talking to an Auth service that uses either gRPC or HTTP for its protocol.

Both methods allow the configuration of what headers to forward to the Auth service, with the HTTP protocol allowing some extra information like a prefix path.

A HTTP example might look like this (noting that this example requires the Experimental channel to be installed and an implementation that supports External Auth to actually understand the config):

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: require-auth
  namespace: default
spec:
  parentRefs:
    - name: your-gateway-here
  rules:
    - matches:
      - path:
          type: Prefix
          value: /admin
      filters:
        - type: ExternalAuth
          externalAuth:
            protocol: HTTP
            backendRef:
              name: auth-service
            http:
              # These headers are always sent for the HTTP protocol,
              # but are included here for illustrative purposes
              allowedHeaders:
                - Host
                - Method
                - Path
                - Content-Length
                - Authorization
      backendRefs:
        - name: admin-backend
          port: 8080

This allows the backend Auth service to use the supplied headers to make a determination about the authentication for the request.

When a request is allowed, the external Auth service will respond with a 200 HTTP response code, and optionally extra headers to be included in the request that is forwarded to the backend. When the request is denied, the Auth service will respond with a 403 HTTP response.

Since the Authorization header is used in many authentication methods, this method can be used to do Basic, Oauth, JWT, and other common authentication and authorization methods.

Mesh resource

Lead(s): Flynn

GEP-3949: Mesh-wide configuration and supported features

Gateway API v1.4.0 introduces a new experimental Mesh resource, which provides a way to configure mesh-wide settings and discover the features supported by a given mesh implementation. This resource is analogous to the Gateway resource and will initially be mainly used for conformance testing, with plans to extend its use to off-cluster Gateways in the future.

The Mesh resource is cluster-scoped and, as an experimental feature, is named XMesh and resides in the gateway.networking.x-k8s.io API group. A key field is controllerName, which specifies the mesh implementation responsible for the resource. The resource's status stanza indicates whether the mesh implementation has accepted it and lists the features the mesh supports.

One of the goals of this GEP is to avoid making it more difficult for users to adopt a mesh. To simplify adoption, mesh implementations are expected to create a default Mesh resource upon startup if one with a matching controllerName doesn't already exist. This avoids the need for manual creation of the resource to begin using a mesh.

The new XMesh API kind, within the gateway.networking.x-k8s.io/v1alpha1 API group, provides a central point for mesh configuration and feature discovery (source).

A minimal XMesh object specifies the controllerName:

apiVersion: gateway.networking.x-k8s.io/v1alpha1
kind: XMesh
metadata:
  name: one-mesh-to-mesh-them-all
spec:
  controllerName: one-mesh.example.com/one-mesh

The mesh implementation populates the status field to confirm it has accepted the resource and to list its supported features ( source):

status:
  conditions:
    - type: Accepted
      status: "True"
      reason: Accepted
  supportedFeatures:
    - name: MeshHTTPRoute
    - name: OffClusterGateway

Introducing default Gateways

Lead(s): Flynn

GEP-3793: Allowing Gateways to program some routes by default.

For application developers, one common piece of feedback has been the need to explicitly name a parent Gateway for every single north-south Route. While this explicitness prevents ambiguity, it adds friction, especially for developers who just want to expose their application to the outside world without worrying about the underlying infrastructure's naming scheme. To address this, we have introduce the concept of Default Gateways.

For application developers: Just "use the default"

As an application developer, you often don't care about the specific Gateway your traffic flows through, you just want it to work. With this enhancement, you can now create a Route and simply ask it to use a default Gateway.

This is done by setting the new useDefaultGateways field in your Route's spec.

Here’s a simple HTTPRoute that uses a default Gateway:

apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: my-route
spec:
  useDefaultGateways: All
  rules:
  - backendRefs:
    - name: my-service
      port: 80

That's it! No more need to hunt down the correct Gateway name for your environment. Your Route is now a "defaulted Route."

For cluster operators: You're still in control

This feature doesn't take control away from cluster operators ("Chihiro"). In fact, they have explicit control over which Gateways can act as a default. A Gateway will only accept these defaulted Routes if it is configured to do so.

You can also use a ValidatingAdmissionPolicy to either require or even forbid for Routes to rely on a default Gateway.

As a cluster operator, you can designate a Gateway as a default by setting the (new) .spec.defaultScope field:

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: my-default-gateway
  namespace: default
spec:
  defaultScope: All
  # ... other gateway configuration

Operators can choose to have no default Gateways, or even multiple.

How it works and key details

  • To maintain a clean, GitOps-friendly workflow, a default Gateway does not modify the spec.parentRefs of your Route. Instead, the binding is reflected in the Route's status field. You can always inspect the status.parents stanza of your Route to see exactly which Gateway or Gateways have accepted it. This preserves your original intent and avoids conflicts with CD tools.

  • The design explicitly supports having multiple Gateways designated as defaults within a cluster. When this happens, a defaulted Route will bind to all of them. This enables cluster operators to perform zero-downtime migrations and testing of new default Gateways.

  • You can create a single Route that handles both north-south traffic (traffic entering or leaving the cluster, via a default Gateway) and east-west/mesh traffic (traffic between services within the cluster), by explicitly referencing a Service in parentRefs.

Default Gateways represent a significant step forward in making the Gateway API simpler and more intuitive for everyday use cases, bridging the gap between the flexibility needed by operators and the simplicity desired by developers.

Configuring client certificate validation

Lead(s): Arko Dasgupta, Katarzyna Łach

GEP-91: Address connection coalescing security issue

This release brings updates for configuring client certificate validation, addressing a critical security vulnerability related to connection reuse. HTTP connection coalescing is a web performance optimization that allows a client to reuse an existing TLS connection for requests to different domains. While this reduces the overhead of establishing new connections, it introduces a security risk in the context of API gateways. The ability to reuse a single TLS connection across multiple Listeners brings the need to introduce shared client certificate configuration in order to avoid unauthorized access.

Why SNI-based mTLS is not the answer

One might think that using Server Name Indication (SNI) to differentiate between Listeners would solve this problem. However, TLS SNI is not a reliable mechanism for enforcing security policies in a connection coalescing scenario. A client could use a single TLS connection for multiple peer connections, as long as they are all covered by the same certificate. This means that a client could establish a connection by indicating one peer identity (using SNI), and then reuse that connection to access a different virtual host that is listening on the same IP address and port. That reuse, which is controlled by client side heuristics, could bypass mutual TLS policies that were specific to the second listener configuration.

Here's an example to help explain it:

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: wildcard-tls-gateway
spec:
  gatewayClassName: example
  listeners:
  - name: foo-https
    protocol: HTTPS
    port: 443
    hostname: foo.example.com
    tls:
      certificateRefs:
      - group: "" # core API group
        kind: Secret
        name: foo-example-com-cert  # SAN: foo.example.com
  - name: wildcard-https
    protocol: HTTPS
    port: 443
    hostname: "*.example.com"
    tls:
      certificateRefs:
      - group: "" # core API group
        kind: Secret
        name: wildcard-example-com-cert # SAN: *.example.com

I have configured a Gateway with two listeners, both having overlapping hostnames. My intention is for the foo-http listener to be accessible only by clients presenting the foo-example-com-cert certificate. In contrast, the wildcard-https listener should allow access to a broader audience using any certificate valid for the *.example.com domain.

Consider a scenario where a client initially connects to foo.example.com. The server requests and successfully validates the foo-example-com-cert certificate, establishing the connection. Subsequently, the same client wishes to access other sites within this domain, such as bar.example.com, which is handled by the wildcard-https listener. Due to connection reuse, clients can access wildcard-https backends without an additional TLS handshake on the existing connection. This process functions as expected.

However, a critical security vulnerability arises when the order of access is reversed. If a client first connects to bar.example.com and presents a valid bar.example.com certificate, the connection is successfully established. If this client then attempts to access foo.example.com, the existing connection's client certificate will not be re-validated. This allows the client to bypass the specific certificate requirement for the foo backend, leading to a serious security breach.

The solution: per-port TLS configuration

The updated Gateway API gains a tls field in the .spec of a Gateway, that allows you to define a default client certificate validation configuration for all Listeners, and then if needed override it on a per-port basis. This provides a flexible and powerful way to manage your TLS policies.

Here’s a look at the updated API definitions (shown as Go source code):

// GatewaySpec defines the desired state of Gateway.
type GatewaySpec struct {
    ...
    // GatewayTLSConfig specifies frontend tls configuration for gateway.
    TLS *GatewayTLSConfig `json:"tls,omitempty"`
}

// GatewayTLSConfig specifies frontend tls configuration for gateway.
type GatewayTLSConfig struct {
    // Default specifies the default client certificate validation configuration
    Default TLSConfig `json:"default"`

    // PerPort specifies tls configuration assigned per port.
    PerPort []TLSPortConfig `json:"perPort,omitempty"`
}

// TLSPortConfig describes a TLS configuration for a specific port.
type TLSPortConfig struct {
    // The Port indicates the Port Number to which the TLS configuration will be applied.
    Port PortNumber `json:"port"`

    // TLS store the configuration that will be applied to all Listeners handling
    // HTTPS traffic and matching given port.
    TLS TLSConfig `json:"tls"`
}

Breaking changes

Standard GRPCRoute - .spec field required (technicality)

The promotion of GRPCRoute to Standard introduces a minor but technically breaking change regarding the presence of the top-level .spec field. As part of achieving Standard status, the Gateway API has tightened the OpenAPI schema validation within the GRPCRoute CustomResourceDefinition (CRD) to explicitly ensure the spec field is required for all GRPCRoute resources. This change enforces stricter conformance to Kubernetes object standards and enhances the resource's stability and predictability. While it is highly unlikely that users were attempting to define a GRPCRoute without any specification, any existing automation or manifests that might have relied on a relaxed interpretation allowing a completely absent spec field will now fail validation and must be updated to include the .spec field, even if empty.

Experimental CORS support in HTTPRoute - breaking change for allowCredentials field

The Gateway API subproject has introduced a breaking change to the Experimental CORS support in HTTPRoute, concerning the allowCredentials field within the CORS policy. This field's definition has been strictly aligned with the upstream CORS specification, which dictates that the corresponding Access-Control-Allow-Credentials header must represent a Boolean value. Previously, the implementation might have been overly permissive, potentially accepting non-standard or string representations such as true due to relaxed schema validation. Users who were configuring CORS rules must now review their manifests and ensure the value for allowCredentials strictly conforms to the new, more restrictive schema. Any existing HTTPRoute definitions that do not adhere to this stricter validation will now be rejected by the API server, requiring a configuration update to maintain functionality.

Improving the development and usage experience

As part of this release, we have improved some of the developer experience workflow:

  • Added Kube API Linter to the CI/CD pipelines, reducing the burden of API reviewers and also reducing the amount of common mistakes.
  • Improving the execution time of CRD tests with the usage of envtest.

Additionally, as part of the effort to improve Gateway API usage experience, some efforts were made to remove some ambiguities and some old tech-debts from our documentation website:

  • The API reference is now explicit when a field is experimental.
  • The GEP (GatewayAPI Enhancement Proposal) navigation bar is automatically generated, reflecting the real status of the enhancements.

Try it out

Unlike other Kubernetes APIs, you don't need to upgrade to the latest version of Kubernetes to get the latest version of Gateway API. As long as you're running Kubernetes 1.26 or later, you'll be able to get up and running with this version of Gateway API.

To try out the API, follow the Getting Started Guide.

As of this writing, seven implementations are already conformant with Gateway API v1.4.0. In alphabetical order:

Get involved

Wondering when a feature will be added? There are lots of opportunities to get involved and help define the future of Kubernetes routing APIs for both ingress and service mesh.

The maintainers would like to thank everyone who's contributed to Gateway API, whether in the form of commits to the repo, discussion, ideas, or general support. We could never have made this kind of progress without the support of this dedicated and active community.