Intended Audience

This page describes who envconfig is built for and where it fits best in your development workflow. Understanding the intended audience helps you decide whether envconfig matches your project's needs and how to apply its conventions effectively.

Who This Library Is For

envconfig is designed for Go developers building applications that read configuration from environment variables — a pattern central to 12-factor app design and cloud-native deployments.

You will get the most out of envconfig if you:

• Write Go applications deployed to containerized or cloud environments (Docker, Kubernetes, AWS ECS, etc.)
• Already understand how environment variables work at the operating system or shell level
• Prefer configuration managed outside the application binary rather than embedded config files
• Want a lightweight, convention-driven approach rather than a large configuration framework

What You Are Expected to Know

envconfig assumes intermediate Go familiarity. Specifically, you should be comfortable with:

• Defining structs and using struct tags
• Understanding basic Go types (string, int, bool, time.Duration, slices)
• Working with Go modules and go get
• Setting environment variables in your shell or container runtime

You do not need deep expertise in reflection or interface implementation to use envconfig day-to-day, though understanding Go interfaces becomes useful if you want to implement a custom decoder for non-standard types.

Where envconfig Fits in Your Stack

envconfig is a small, focused library. It does one thing: map environment variables into a typed Go struct at application startup. It does not manage secrets, poll for config changes at runtime, or integrate with remote configuration stores.

This makes it a strong fit when:

• Your configuration is injected by the environment (CI/CD pipelines, Kubernetes env fields, Docker --env)
• You want configuration validation and type conversion handled automatically
• You prefer your configuration schema to live in code, not in a separate config file format

If you need dynamic config reloading or integration with Vault, Consul, or similar systems, you would use envconfig alongside those tools — not as a replacement.

Typical user scenario: a backend service reading its config at startup

A developer deploying a Go HTTP service to Kubernetes sets environment variables in their deployment manifest and uses envconfig to load them safely at boot.

package main

import (
	"fmt"
	"log"
	"time"

	"github.com/kelseyhightower/envconfig"
)

// Config holds all environment-driven settings for the service.
// Struct tags tell envconfig which environment variable maps to each field.
type Config struct {
	Port        int           `envconfig:"PORT" default:"8080"`
	DatabaseURL string        `envconfig:"DATABASE_URL" required:"true"`
	Timeout     time.Duration `envconfig:"REQUEST_TIMEOUT" default:"30s"`
	Debug       bool          `envconfig:"DEBUG" default:"false"`
}

func main() {
	var cfg Config
	if err := envconfig.Process("", &cfg); err != nil {
		log.Fatalf("failed to load configuration: %v", err)
	}

	fmt.Printf("Listening on port %d\n", cfg.Port)
	fmt.Printf("Connecting to database: %s\n", cfg.DatabaseURL)
	fmt.Printf("Request timeout: %s\n", cfg.Timeout)
}

Environment variables set before running:

export DATABASE_URL="postgres://user:pass@localhost:5432/mydb"
export REQUEST_TIMEOUT="45s"
export DEBUG="true"

Expected output:

Listening on port 8080
Connecting to database: postgres://user:pass@localhost:5432/mydb
Request timeout: 45s

This pattern — define a struct, annotate it with tags, call Process once — is the core workflow envconfig is built around. The library handles type conversion, default values, and required-field validation so your application code stays focused on business logic.

• Defining a configuration struct — How to model your application's configuration using Go structs and envconfig struct tags
• Processing environment variables — The envconfig.Process function and how it maps variables to struct fields
• Default values and required fields — Controlling what happens when an environment variable is absent
• Custom decoders — Extending envconfig to handle types it does not support out of the box
• 12-factor app configuration (external) — The methodology that motivates storing config in the environment