Schema Registries

Anything else is rejected per entry with Unsupported contentType: <value>. Supported types: application/json, application/avro, application/protobuf, application/octet-stream. That includes application/eventbridge+json, which is the value the service stamps on PutEvents traffic and is not accepted as input on PutRawEvents.

Avro and Protobuf are open formats: the service decodes them against a schema registry. Name that registry on the publish request, which is the only place the API accepts one. An open-format entry published without it is rejected per entry.

The request-level field

When you supply SchemaRegistryConfiguration, it MUST sit on the PutRawEvents call itself, as a sibling of Entries rather than inside an entry; one registry serves every entry in the request:

The Python and Java forms of the same call are in code-samples.md.

The registry is read with your own credentials. No role is passed on the request, so the identity publishing the events MUST be allowed to read the registry it names.

Where the registry cannot go

SchemaRegistryConfiguration appears on PutRawEvents and nowhere else in the API, so you MUST NOT configure decoding on the bus, on the subscriber, or on the transformer. Each of the following is absent rather than accepted and ignored, so looking for it only costs time:

So the publisher decides decoding, once per request. A subscriber cannot ask for a different registry, and a bus owner cannot impose one.

The two registry kinds

RegistryUri accepts two forms:

A Confluent registry needs an EventBridge Connection. The ConnectionArn points at a connection holding the API key or OAuth credentials for that registry, and you MUST provide it whenever RegistryUri is an HTTPS URL. The connection keeps that credential in AWS Secrets Manager and hands you back only the connection ARN, so you MUST NOT put the registry credential in your own configuration or in the publish request. Create the connection before the first publish; a Glue ARN needs no connection because the caller’s own credentials cover the access.

When the field is required

SchemaRegistryConfiguration is required for open-format entries and ignored for JSON entries, so always sending it is harmless.

Rejection messages

An open-format entry published without the registry block is rejected with SchemaRegistryConfiguration is required for open-format events, and a payload whose frame does not match the declared format is rejected with a message naming the format.

Schema deserialization is an enriched operation, billed per event (see cost-and-quotas.md).

Running alongside Kafka

During an incremental move to AWS the bus complements a Kafka estate rather than replacing it, and the format support above is the bridge. A producer already encoding Avro against a Confluent registry publishes the same bytes with PutRawEvents, because RegistryUri takes the Confluent Cloud URL, and consumers on the bus side receive decoded JSON without holding the schema or reaching the registry. Crossing the other way, a subscriber delivers to whatever fronts the Kafka estate.

The behavioural difference to plan around is the delivery model. The bus pushes each event to a subscriber’s configured target; nothing polls. There are no consumer groups, no offsets to commit or seek, and no log compaction. The nearest equivalents are one subscriber per consumer in place of a consumer group, replay from retained history in place of an offset seek (replay-and-recovery.md), and publish-time deduplication (chapter 11) in place of compaction.