#1 Koanf
Simple, extremely lightweight, extensible, configuration management library for Go. Supports JSON, TOML, YAML, env, command line, file, S3 etc. Alternative to viper.
github.com/caarlos0/env
env
A simple, zero-dependencies library to parse environment variables into structs
Decision Signals
Health score 54/100, confidence 80/100.
Install
go get github.com/caarlos0/env
Package Data
updated May 31, 2026| Latest version | v3.5.0+incompatible |
| Imported by | 1.4K packages |
| Stars | 0 |
| Forks | 0 |
| Last activity | 7 years ago |
| Latest release | Unknown |
| License | Unknown |
| Known vuln records | 0 |
API Surface
8 symbols| Symbol | Kind | Synopsis |
|---|---|---|
| CustomParsers | Type | type CustomParsers map[reflect.Type]ParserFunc |
| ParserFunc | Type | type ParserFunc func(v string) (interface{}, error) |
| ErrNotAStructPtr | Variable | var ErrNotAStructPtr = errors.New("Expected a pointer to a Struct") |
| ErrUnsupportedSliceType | Variable | var ErrUnsupportedSliceType = errors.New("Unsupported slice type") |
| ErrUnsupportedType | Variable | var ErrUnsupportedType = errors.New("Type is not supported") |
| OnEnvVarSet | Variable | var OnEnvVarSet func(reflect.StructField, string) |
| Parse | Function | func Parse(v interface{}) error |
| ParseWithFuncs | Function | func ParseWithFuncs(v interface{}, funcMap CustomParsers) error |
Maintained Alternatives
limited recent repository activity#2 Viper
Go configuration with fangs.
#3 argus
Package argus provides a comprehensive dynamic configuration management framework for Go applications, combining ultra-fast file monitoring, universal format parsing, and zero-reflection configuration binding in a single, cohesive system.
#4 agent-sdk-go
Go SDK for building durable AI agents on Temporal with support for tools, MCP, human approvals, and sub-agent delegation.
#5 Kono
lightweight extendable API Gateway in Go - parallel fan-out, flexible aggregation, and zero configuration magic.
#6 v2
Package config is a go config management implement.
Similar Packages
Go Configuration Libraries#1 Koanf
Simple, extremely lightweight, extensible, configuration management library for Go. Supports JSON, TOML, YAML, env, command line, file, S3 etc. Alternative to viper.
#2 Viper
Go configuration with fangs.
#3 argus
Package argus provides a comprehensive dynamic configuration management framework for Go applications, combining ultra-fast file monitoring, universal format parsing, and zero-reflection configuration binding in a single, cohesive system.
#4 agent-sdk-go
Go SDK for building durable AI agents on Temporal with support for tools, MCP, human approvals, and sub-agent delegation.
#5 Kono
lightweight extendable API Gateway in Go - parallel fan-out, flexible aggregation, and zero configuration magic.