Systems and methods for generating asynchronous application programming interface (API) documents are generally described. In various examples, a topic discovery request may be sent to a message broker. A list of topics may be received from the message broker. First identifier data identifying a first topic of the list of topics may be received from the message broker. A first message may be received from the message broker, where the first message pertains to the first topic. First schema may be determined using the first message. The first schema data may describe content of the first message and organization of the content of the first message. The first identifier data may be stored in a first data structure in association with the first schema data.