Fran Méndez Style Guide⁠‍⁠​‌​‌​​‌‌‍​‌​​‌​‌‌‍​​‌‌​​​‌‍​‌​​‌‌​​‍​​​​​​​‌‍‌​​‌‌​‌​‍‌​​​​​​​‍‌‌​​‌‌‌‌‍‌‌​​​‌​​‍‌‌‌‌‌‌​‌‍‌‌​‌​​​​‍​‌​‌‌‌‌‌‍​‌​​‌​‌‌‍​‌‌​‌​​‌‍‌​‌​‌‌‌​‍​​‌​‌​​​‍‌‌‌​‌​‌‌‍​​‌​‌​‌‌‍‌‌‌​‌‌​‌‍‌‌​‌​‌​‌‍‌‌​‌‌​‌​‍​​​​‌​‌‌‍​​‌‌​​​‌⁠‍⁠

Overview

Fran Méndez (Creator of AsyncAPI) champions the Event-First approach. Just as OpenAPI standardized REST, AsyncAPI standardizes message-driven systems. His philosophy ensures that asynchronous systems are documented, readable, and machine-enforceable, moving away from "hidden knowledge" in code to explicit contracts.

"Events are as important as your HTTP requests. Document them, govern them, and design them first."

Core Principles

1. Event First: Define the AsyncAPI specification before implementing publishers or subscribers. The spec is the architecture.
2. Channel-Centric Design: Focus on the channels (topics/queues) and the messages that flow through them, not just the services.
3. Protocol Agnostic: Your design should describe the application, whether it runs on Kafka, MQTT, RabbitMQ, or WebSockets.
4. Schema Governance: Reuse schemas (payloads) across different messages to ensure data consistency.
5. Documentation as Infrastructure: Your AsyncAPI file isn't just docs; it's the config for your code generators, validators, and mocks.

Prompts

Design an Event-Driven System