docs/daprdocs/content/en/reference/components-reference/supported-bindings/kafka.md

type	title	linkTitle	description	aliases
docs	Kafka binding spec	Kafka	Detailed documentation on the Kafka binding component	/operations/components/setup-bindings/supported-bindings/kafka/

Component format

To setup Kafka binding create a component of type bindings.kafka. See [this guide]({{< ref "howto-bindings.md#1-create-a-binding" >}}) on how to create and apply a binding configuration. For details on using secretKeyRef, see the guide on [how to reference secrets in components]({{< ref component-secrets.md >}}).

All component metadata field values can carry [templated metadata values]({{< ref "component-schema.md#templated-metadata-values" >}}), which are resolved on Dapr sidecar startup. For example, you can choose to use {namespace} as the consumerGroup, to enable using the same appId in different namespaces using the same topics as described in [this article]({{< ref "howto-namespace.md#with-namespace-consumer-groups">}}).

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: kafka-binding
spec:
  type: bindings.kafka
  version: v1
  metadata:
  - name: topics # Optional. Used for input bindings.
    value: "topic1,topic2"
  - name: brokers # Required.
    value: "localhost:9092,localhost:9093"
  - name: consumerGroup # Optional. Used for input bindings.
    value: "group1"
  - name: publishTopic # Optional. Used for output bindings.
    value: "topic3"
  - name: authRequired # Required.
    value: "true"
  - name: saslUsername # Required if authRequired is `true`.
    value: "user"
  - name: saslPassword # Required if authRequired is `true`.
    secretKeyRef:
      name: kafka-secrets
      key: saslPasswordSecret
  - name: initialOffset # Optional. Used for input bindings.
    value: "newest"
  - name: maxMessageBytes # Optional.
    value: 1024
  - name: version # Optional.
    value: 1.0.0

Spec metadata fields

Field	Required	Binding support	Details	Example
topics	N	Input	A comma-separated string of topics.	"mytopic1,topic2"
brokers	Y	Input/Output	A comma-separated string of Kafka brokers.	"localhost:9092,dapr-kafka.myapp.svc.cluster.local:9093"
clientID	N	Input/Output	A user-provided string sent with every request to the Kafka brokers for logging, debugging, and auditing purposes.	"my-dapr-app"
consumerGroup	N	Input	A kafka consumer group to listen on. Each record published to a topic is delivered to one consumer within each consumer group subscribed to the topic.	"group1"
consumeRetryEnabled	N	Input/Output	Enable consume retry by setting to "true". Default to false in Kafka binding component.	"true", "false"
publishTopic	Y	Output	The topic to publish to.	"mytopic"
authRequired	N	Deprecated	Enable SASL authentication with the Kafka brokers.	"true", "false"
authType	Y	Input/Output	Configure or disable authentication. Supported values: none, password, mtls, or oidc	"password", "none"
saslUsername	N	Input/Output	The SASL username used for authentication. Only required if authRequired is set to "true".	"adminuser"
saslPassword	N	Input/Output	The SASL password used for authentication. Can be secretKeyRef to use a [secret reference]({{< ref component-secrets.md >}}). Only required if authRequired is set to "true".	"", "KeFg23!"
initialOffset	N	Input	The initial offset to use if no offset was previously committed. Should be "newest" or "oldest". Defaults to "newest".	"oldest"
maxMessageBytes	N	Input/Output	The maximum size in bytes allowed for a single Kafka message. Defaults to 1024.	2048
oidcTokenEndpoint	N	Input/Output	Full URL to an OAuth2 identity provider access token endpoint. Required when authType is set to oidc	"https://identity.example.com/v1/token"
oidcClientID	N	Input/Output	The OAuth2 client ID that has been provisioned in the identity provider. Required when authType is set to oidc	dapr-kafka
oidcClientSecret	N	Input/Output	The OAuth2 client secret that has been provisioned in the identity provider: Required when authType is set to oidc	"KeFg23!"
oidcScopes	N	Input/Output	Comma-delimited list of OAuth2/OIDC scopes to request with the access token. Recommended when authType is set to oidc. Defaults to "openid"	"openid,kafka-prod"

Binding support

This component supports both input and output binding interfaces.

This component supports output binding with the following operations:

• create

Authentication

Kafka supports a variety of authentication schemes and Dapr supports several: SASL password, mTLS, OIDC/OAuth2. [Learn more about Kafka's authentication method for both the Kafka binding and Kafka pub/sub components]({{< ref "setup-apache-kafka.md#authentication" >}}).

Specifying a partition key

When invoking the Kafka binding, its possible to provide an optional partition key by using the metadata section in the request body.

The field name is partitionKey.

Example:

curl -X POST http://localhost:3500/v1.0/bindings/myKafka \
  -H "Content-Type: application/json" \
  -d '{
        "data": {
          "message": "Hi"
        },
        "metadata": {
          "partitionKey": "key1"
        },
        "operation": "create"
      }'

Response

An HTTP 204 (No Content) and empty body will be returned if successful.

Related links

• [Basic schema for a Dapr component]({{< ref component-schema >}})
• [Bindings building block]({{< ref bindings >}})
• [How-To: Trigger application with input binding]({{< ref howto-triggers.md >}})
• [How-To: Use bindings to interface with external resources]({{< ref howto-bindings.md >}})
• [Bindings API reference]({{< ref bindings_api.md >}})