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Quick Start for Schema Management on Confluent Cloud

You can use Confluent Cloud Schema Registry to manage schemas in Confluent Cloud. You enable a single Schema Registry per Confluent Cloud environment. Schema Registry is accessed over port 443.

You can create and edit schemas in a schema editor and associate them with Kafka topics.

This quick start does not cover all the capabilities of Schema Registry, but rather is an introduction. For a complete guide, see Manage Schemas in Confluent Cloud.

Important

• Your VPC must be able to communicate with the Confluent Cloud Schema Registry public internet endpoint. For more information, see Use Confluent Cloud Schema Registry in a VPC-peered environment.
• This quick start assumes that you have completed Quick Start for Apache Kafka using Confluent Cloud, including installing and using the Confluent Cloud CLI.
• This quick start requires that you use both the Confluent Cloud Console and the Confluent Cloud CLI. (A handy list of CLI commands is here.)

Log in to the Cloud Console

1. Log in to Confluent Cloud at https://confluent.cloud.
2. Select an environment or create a new one.

Enable Schema Registry for Confluent Cloud

1. Select an environment.

2. Click the Schema Registry tab.

3. Click Set up on my own (or choose the guided path).

4. Choose a cloud provider and geography (which will map to a region under the hood).

   • Select Amazon Web Services (AWS), Google Cloud Platform (GCP), or Azure
   • Choose a Region. US, Europe, and APAC are the available choices.
   • Click Enable Schema Registry.
   

   Tip

   For each cloud provider, geographies are mapped under the hood to the following regions:

   • GCP US: us-central1
   • GCP EU: europe-west3
   • GCP APAC: australia-southeast1
   • AWS US: us-east-2
   • AWS EU: eu-central-1
   • AWS APAC: ap-southeast-2
   • Azure US: westus2
   • Azure EU: westeurope
   • Azure APAC: southeastasia

5. Review your settings, and click Continue to create the Schema Registry with these cloud provider and region settings.

   This creates a Schema Registry to serve all clusters in the current environment. The environment level Schema Registry settings page is displayed.

   

   An empty schemas list is shown, indicating no schemas have yet been created.

   

Create an API Key for Confluent Cloud Schema Registry

To use Confluent Cloud Schema Registry for managing Kafka clusters, you need an API key specific to Schema Registry.

Note

• The API key for Confluent Cloud Schema Registry is distinct from the API key you created for Kafka clusters in the same environment, per the Quick Start for Apache Kafka using Confluent Cloud.
• Confluent Cloud provides one Schema Registry per environment, and each environment can contain multiple Kafka clusters. You need an API key/secret pair for each Kafka cluster and another for the Schema Registry cluster.

1. In the environment for which you want to set up Schema Registry, click the Schema Registry tab, then click Edit on the API credentials card.

   

2. Click Create key to create a new Schema Registry API key.

   

3. When the API Key and API Secret are saved, click the checkbox next to I have saved my API key and secret and am ready to continue, and click Continue.

   

   Your new Schema Registry key is shown on the Schema Registry API access key list.

   

Schema Registry API Keys for Multi-Tenant Clusters

Confluent Cloud supports one Schema Registry per environment. In multi-tenant deployments, one physical Schema Registry per cloud and geographic region hosts many logical schema registries. In these cases, the registries for different Kafka clusters in different environments will have the same URL as the Confluent Cloud Schema Registry. Confluent Cloud uses the Schema Registry API keys to store schemas and route requests to the appropriate logical clusters.

Tip

To learn more about other environment level schema management options available on the Environment settings page, see Configure and Manage Schemas for an Environment.

Create a Topic in Confluent Cloud

You may already have topics available on this cluster, having worked through the prerequisite Quick Start for Apache Kafka using Confluent Cloud, but create a new topic designed to test out Schema Registry.

1. Select the environment.

   Tip

   If you have only one environment, default, it will be selected already.

2. Select the cluster.

3. Click Topics on the left menu, then click Create topic.

   

   Name the new topic employees, and click Create with defaults to add it.

Create a Schema

You can create schemas for topics from the web UI, or from the Confluent Cloud CLI. This section shows you how to create a schema from the Confluent Cloud CLI, just to provide a 360 view of cloud tools and demonstrate how you can use the web UI and the CLI to interact with the same entities, such as environments, clusters, topics, and schemas.

If you need more help with the basic CLI commands, type confluent --help, confluent schema-registry --help to drill down, or see Quick Start for Apache Kafka using Confluent Cloud and the Confluent CLI command reference.

1. Log in to the Confluent Cloud CLI.

   confluent login
   

   Follow the prompts to enter your credentials (email and password).

   Upon login, Confluent Cloud indicates your current environment.

   Enter your Confluent credentials:
   Email:
   Password:
   
   Using environment t2814 ("my-cloud-demos")
   

2. Select the environment where you created the employees topic. (It may already be selected upon login.)

   In order to verify this, use confluent environment list to get the environment IDs, followed by confluent environment use <ID> to select the environment you want (if it is not already the current environment).

   For example:

   confluent environment list
   

   Your output should resemble:

         Id      |        Name
   +-------------+--------------------+
     * t2703     | default
       env-vnywz | ccloud-demo
       env-qzrg2 | data-lineage-demo
       env-250o2 | my-new-environment
   

   To use “ccloud-demo”:

   confluent environment use env-vnywz
   

   Tip

   • To list environments: confluent environment list
   • To select an environment: confluent environment use <environment ID>
   • To list clusters: confluent kafka cluster list
   • To select a cluster: confluent kafka cluster use <cluster ID>
   • For the full list of confluent commands see Confluent CLI command reference.

3. Create a file containing the following JSON and name it employees.json.

   {
      "type" : "record",
      "namespace" : "Example",
      "name" : "Employee",
      "fields" : [
         { "name" : "Name" , "type" : "string" },
         { "name" : "Age" , "type" : "int" }
      ]
   }
   

4. Create a schema that uses employees.json.

   confluent schema-registry schema create --subject employees-value --schema employees.json --type AVRO
   

   For example:

   confluent schema-registry schema create --subject employees-value --schema employees.json --type AVRO
   
   Enter your Schema Registry API Key:
   xxxx
   Enter your Schema Registry API Secret:
   xxxxyyyyzzzz
   Successfully registered schema with ID: 100001
   

   Tip

   • You have the option to create schemas that reference other schemas by using the --refs <ref-file> flag with confluent schema-registry schema create. To learn more about schema references, see Schema References in the Confluent Platform documentation. You can also create schema references from the web UI.

   • You must specify a schema format type as one of AVRO, JSON, or PROTOBUF, and then supply a schema that conforms to the syntax for that type. To learn more about development using these schema formats, see Schema Formats, Serializers, and Deserializers in the Confluent Platform documentation, the JSON Schema project documentation, the Apache Avro® specification, and the Google Developer documentation on Protocol Buffers.

   • You can also create a schema from the web UI. To do so, select an environment and cluster, select a topic, then click the Schema tab for that topic. Select a schema format type (for this example, Avro), paste the schema (such as the employees.json content), and click Save.

     

View the Topic and Associated Schema

Return to the Cloud Console to view the new schema for the employees topic.

1. Navigate to the topics list for your cluster.

   

2. Click the employees topic you created in a previous step.

3. Click Schema.

   

   And there you have it! You have a new schema (employees-value) for the employees topic in Confluent Cloud Schema Registry.

Configure and Manage Schemas for an Environment

Several tasks related to schemas on Confluent Cloud are managed at the environment level. This includes creating and managing Schema Registry API keys along with options, as described below, to view and search schemas, monitor usage, and set a compatibility mode for schemas.

View and Search All Schemas in an Environment

To view a searchable list of all schemas available in a Confluent Cloud environment:

1. Select an environment.

2. Click the Schemas Registry tab.

3. On the Schemas card, click View and manage schemas.

   

   The schemas list is shown.

   
   • You can use Search to find schemas in longer lists
   • Click a schema to drill down for more options, including view, download, duplicate, or delete a schema; navigate to compatibility settings; traverse the schema version history, view each version, and compare versions.
   • Also shown at the top of this page is the number of schemas available in the environment compared to the usage limit. See the next section to learn more.

View Allowed Usage for Schemas on Confluent Cloud

Schema Registry in Confluent Cloud limits the number of schema versions supported in the registry for basic clusters, standard clusters, and dedicated clusters as described in Confluent Cloud Features and Limits by Cluster Type. You can view the number of schemas you have in an environment compared to the allowed usage limit.

1. Select an environment.

2. Click the Schemas Registry tab.

3. On the Schemas card, click View and manage schemas.

   The schemas list is shown. The number of schemas in use compared to the number of available schemas is shown at the top.

   

To learn more about how to manage schema usage on Confluent Cloud, see how to free up space for new schemas.

View and Edit Global Compatibility Settings on Schemas

The default compatibility mode is Backward. From the environment level Schema Registry settings, you can change the mode, which will apply globally to all schemas in an environment. You can also change compatibility settings for a schema on a specific topic (at the subject level). Subject-level compatibility settings override the global settings.

Caution

If you change the compatibility mode of existing schemas already in production use, be aware of any possible breaking changes to your applications.

1. Select an environment.

2. Click the Schema Registry tab.

3. Click Edit on the Compatibility setting card.

   

   The Compatibility settings are shown.

   

4. Select a mode option:

   • Backward (Confluent Schema Registry default)
   • Transitive backward
   • Forward and Transitive forward
   • Full and Transitive full
   • None (not recommended)

   Descriptions indicate the compatibility behavior for each option. For more information, including the changes allowed for each option, see Schema Evolution and Compatibility.

5. Click Save.

Use curl to View and Manage Schemas

You can also use curl commands to view and manage schemas on Confluent Cloud.

Schema Registry on Confluent Cloud requires that you pass the API Key and Secret with the --user (or -u) flag. For example, to view all subjects in the registry:

curl --user <schema-registry-api-key>:<schema-registry-api-secret> \
<schema-registry-url>/subjects

For more information about using curl commands with Schema Registry, see Schema Registry API Usage Examples. With the exception of this one same example, the examples are for on-premises Schema Registry but many of the commands are relevant to Confluent Cloud, once you know how to pass your API Key and Secret as shown here.

Suggested Reading

Schemas Product Documentation

• Working with schemas
• Stream Governance Overview
• Confluent Cloud Schema Registry Tutorial
• Quick Start for Apache Kafka using Confluent Cloud
• Confluent Cloud Console
• Confluent Cloud CLI Schema Registry commands
• Schema Management
• Migrate Schemas
• Confluent Cloud schemas limits and how to free up space
• Schema Formats, Serializers, and Deserializers (Confluent Platform tools that support application development for Confluent Cloud and self-managed systems)
• Run an automated Confluent Cloud quickstart with Avro, Protobuf, and JSON formats

Blog Posts and Podcasts

• Blog post: Getting Started with Protobuf in Confluent Cloud
• Blog post: Confluent Platform Now Supports Protobuf, JSON Schema, and Custom Formats
• Blog post: Confluent Cloud Schema Registry is Now Generally Available
• Podcast: Schema Registry Made Simple