The Power of Simplicity in a World of Complex Messaging.
While powerful messaging systems like Apache Kafka and RabbitMQ dominate the enterprise, they often come with significant operational complexity. NATS.io offers a radically different approach, rooted in simplicity, performance, and resilience. It is a lightweight, open source messaging system that provides a flexible communication fabric for everything from simple fire and forget messaging to request-reply patterns, and even durable streaming with NATS JetStream.
But this simplicity can be misleading. An engineer who treats NATS as a "dumb pipe" will fail to leverage its powerful features for building resilient and scalable systems. An expert understands the trade offs between core NATS and JetStream, knows how to design a subject hierarchy for effective message routing, and can build applications that handle the realities of an "at most once" messaging guarantee when using core NATS.
This playbook explains how Axiom Cortex vets for a deep, practical understanding of NATS, finding engineers who can use its elegant design to build fast, reliable, and easy-to-operate cloud native systems.
Traditional Vetting and Vendor Limitations
A vendor who can vet for deep NATS expertise is exceptionally rare. Most will see it on a résumé and lump it in with other messaging systems, failing to test for the specific knowledge required to use it effectively.
The result is often an application that is brittle and fails to meet its reliability goals:
- Misunderstanding Delivery Guarantees: A developer uses core NATS for a critical workflow that requires guaranteed delivery, not realizing that it provides "at most once" semantics. Messages are lost during network partitions or broker restarts.
- Inefficient Subject Design: The team uses a flat, unstructured subject hierarchy, making it impossible to use wildcards for flexible message consumption.
- Ignoring JetStream: The team tries to build their own persistence and durability layer on top of core NATS, unaware that NATS JetStream provides this out of the box with features like streams and consumers.
How Axiom Cortex Evaluates NATS Developers
Axiom Cortex is designed to find engineers who appreciate the power of simplicity and understand the trade offs in distributed messaging. We evaluate candidates across three critical dimensions.
Dimension 1: Core NATS vs. JetStream
This is the fundamental architectural choice when building with NATS. This dimension tests a candidate's ability to choose the right tool for the job.
We provide a use case and evaluate their ability to:
- Explain the Trade-offs: Can they explain when the high performance, "at most once" semantics of core NATS are appropriate versus when the durability and "at least once" guarantees of JetStream are required?
- Design a JetStream Solution: Can they design a system using JetStream streams, consumers, and acknowledgement policies to build a reliable message processing workflow?
Dimension 2: Subject-Based Messaging and Routing
NATS's power and flexibility come from its subject-based addressing. This dimension tests a candidate's ability to design a clean and effective subject hierarchy.
We present a messaging problem and evaluate if they can:
- Design a Subject Hierarchy: Can they design a hierarchical subject space (e.g., `orders.us.new`, `orders.eu.new`) that allows for flexible consumption using wildcards (`orders.us.*` or `orders.*.new`)?
- Implement Request-Reply Patterns: Do they know how to use NATS to implement synchronous request-reply interactions between services?
Dimension 3: Operations and Resilience
An elite NATS developer understands how to run and scale it in a production environment.
We evaluate their knowledge of:
- Cluster Architecture: Can they explain how to set up a resilient, multi-node NATS cluster?
- Security: Are they familiar with configuring NATS security using accounts, users, and permissions?
The Nervous System of Modern Applications
When you staff your team with engineers who have passed the NATS.io Axiom Cortex assessment, you are investing in a team that can build the lightweight, high performance, and resilient messaging backbone that modern microservices and edge applications require. They will be able to build systems that are both powerful and operationally simple, a rare and valuable combination in today's complex cloud native world. For other caching or fast data access needs, they might use tools like Memcached or Redis.