aero

Aero

Aero is a small Clojure/ClojureScript library for explicit, intentional EDN configuration. It extends EDN with tag literals that handle environment variables, profiles, file inclusion, cross-references, and more — without resorting to Turing-complete configuration languages.

Coordinates: [aero "1.1.6"] / {aero/aero {:mvn/version "1.1.6"}}

Quick Decision: What do you need?

Task	Go to
Load config, understand read-config, resolvers, profiles	getting-started.md
Full reference for every built-in tag literal	tag-literals.md
Patterns: secrets, components, feature flags, schema validation	patterns.md
Define your own tag literals via reader multimethod or alpha macro API	extending.md
Common mistakes and things to avoid	anti-patterns.md

Core Mental Model

Aero reads an EDN file and resolves tag literals in a single pass (with a fixpoint loop to handle forward #ref references). The result is a plain Clojure map — no special types, no lazy resolution at call sites. Tag literals are resolved at read time, not at access time.

read-config accepts a source (file path, java.io.File, java.net.URL, classpath resource) and an optional options map:

(require '[aero.core :refer [read-config]])

;; From classpath (recommended for production):
(read-config (clojure.java.io/resource "config.edn"))

;; With profile:
(read-config (clojure.java.io/resource "config.edn") {:profile :prod})

The default profile is :default. Every #profile map should include a :default key as a fallback.