I need to ingest data into my application. There is a Kafka stream already build for data ingestion. One of the client's requirement needs an API interface for accepting the data. So I need an API management solution which provides API gateway functionality and is able to produce message on a Kafka topic.
I have analyzed Kong + Kong-upstream plugin. But looking for any other similar solution
You can check WSO2 Api Manager.
check this article for wso2 kafka integration. https://ei.docs.wso2.com/en/7.2.0/micro-integrator/references/connectors/kafka-connector/kafka-connector-producer-example/
Also you can write your custom mediator for WSO2.
Another Solution;
If you need different solution else that api gateway. You can check Apache Nifi. It's application that you create your flow. You can do anything what you want.
Apache Nifi's Documentation
For your problem you need to check this Apache Nifi's processors;
-PublishKafka + ConsumeKafka -ListenHTTP
Edit after @OneCricketeer's comment:
Kafka Solution Without any Integration
Kafka REST Proxy