# ASSERT TOPIC statement in ksqlDB for Confluent Platform ## Synopsis ```sql ASSERT (NOT EXISTS)? TOPIC topicName (WITH properties)? (TIMEOUT timeout); ``` ## Description Asserts that a topic exists or does not exist. If properties are specified in an `ASSERT TOPIC` statement, then ksqlDB will also check that the property values match. The only properties that will be checked are `PARTITIONS` and `REPLICAS`. Trying to check any other properties will result in the assertion failing. Properties will not be checked in an `ASSERT NOT EXISTS` statement. The `TIMEOUT` clause specifies the amount of time to wait for the assertion to succeed before failing. If the `TIMEOUT` clause is not present, then ksqlDB will use the timeout specified by the server configuration `ksql.assert.topic.default.timeout.ms`, which is 1000 ms by default. If the assertion fails, then an error will be returned.