How to insert messages into a Kafka topic via Lenses UI (getting "Cannot insert data" message)

Hello, Is it mandatory to have a schema for a topic when inserting some test messages into a topic from lenses ?

One way to get around Lenses enforcing a schema is to use the SQL Studio to create a topic and then using INSERT SQL statements to insert data.

Eg. Create the topic with:

CREATE TABLE mytopic (_key string, name string, number string[])
   (string, json)
PROPERTIES  (partitions=1, compacted=false);

…and then insert events as JSON objects:

INSERT INTO mytopic (_key, name, number)
   ("user1","John Doe", ["555-1234","555-5678"])