Kong Event Gateway known limitations

Kong Event Gateway currently has the following limitations:

• Queues for Kafka are not supported
• The new consumer rebalance protocol is not supported
• Client metrics and observability for clients is not supported (you may need to set enable.metrics.push=false on recent java clients).
• SASL Handshake v0 is not supported as it is being removed in Kafka 4.0 (see Kafka Improvement Proposal 896).

• Compacted topics used with policies and namespaces are untested

Kafka record headers are multi-valued: the Kafka protocol allows the same header key to appear more than once in a single record, and clients can read every occurrence.

Event Gateway models record headers as a single value per key. When a record is processed by a policy that reads or transforms headers (for example, Encryption, Schema Validation, or Modify Headers policies), records that carry duplicate header keys are collapsed so that only the last value for each key is kept. Earlier values with the same key are dropped.

This only affects records that Event Gateway decodes to apply record-level policies. If your clients rely on multiple headers that share the same key, don’t route those topics through header-transforming policies.

See the Kong Event Gateway headers reference for the headers Event Gateway adds and interprets.