Enver

A fast, strict, opinionated .env file parser for .NET.

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Enver is built to:

• Parse common .env syntax
• Reject malformed or ambiguous input
• Fail fast with clear error messages

See PARSING.md for the full grammar and enforcement philosophy.

It supports:

• Value interpolation (NAME=World + GREETING="Hello ${NAME}!" = GREETING="Hello World!")
• Line-level and inline comments (KEY=value # This comment won't be parsed)
• Multi-level .env file loading
• Variant files (.env.{variant}) with correct precedence

Parsed output can be sent to:

• An in-memory dictionary
• System.Environment
• ASP.NET Core configuration
• A strongly-typed class via source-generated binding

What's in the box

The base package contains the core parser. Pick an integration package based on where you want the values to go:

Package	Use case
Enver	Core lexer + parser. Reference directly only if you're writing a custom consumer.
Enver.Binding	Strongly-typed configuration binding.
Enver.InMemory	Load .env files into an EnvCollection (a Dictionary<string, string> subclass with platform-appropriate key comparison).
Enver.SystemEnvironment	Load .env files into the process environment block via Environment.SetEnvironmentVariable. Useful when downstream code already uses Environment.GetEnvironmentVariable(...) and you want to keep that flow.
Enver.Extensions.Configuration	IConfigurationSource integration for ASP.NET Core / Microsoft.Extensions.Configuration. Plus IConfiguration.AsEnvReader() so Enver's typed accessors apply to any configuration source, not just .env files.

Quick start

Load .env into a dictionary

dotnet add package Gnar.Enver.InMemory

using Enver;

// Reads .env from the executable's directory.
var values = EnvCollection.From(DotEnvPaths.AppDirectory());

var dbHost = values["DB_HOST"];

EnvCollection is a Dictionary subclass, so all standard dictionary operations apply.

Load .env into the process environment

dotnet add package Gnar.Enver.SystemEnvironment

using Enver;

// C# 14+ only
Environment.LoadDotEnv(DotEnvPaths.AppDirectory());
// OR
EnvironmentExtensions.LoadDotEnv(DotEnvPaths.AppDirectory());

var dbHost = Environment.GetEnvironmentVariable("DB_HOST");

Load .env into ASP.NET Core configuration

dotnet add package Gnar.Enver.Extensions.Configuration

using Enver.Extensions.Configuration;

var builder = WebApplication.CreateBuilder(args);
builder.Configuration.AddDotEnvFiles();
// loads .env, .env.{environment}, .env.local, .env.{environment}.local
// in precedence order; every file is optional

string? dbHost = builder.Configuration["DB_HOST"];
int port = builder.Configuration.AsEnvReader().GetInt32("DB_PORT", 5432);

Bind .env to a typed class

dotnet add package Gnar.Enver.Binding

using Enver;
using Enver.Binding;

[EnvBindable]
public partial record DatabaseConfig(string Host, int Port)
{
    public bool UseSsl { get; init; } = true;
}

var cfg = DatabaseConfig.Bind(DotEnvPaths.AppDirectory());
// property names map to UPPER_SNAKE_CASE: Host -> HOST, UseSsl -> USE_SSL

Add System.ComponentModel.DataAnnotations attributes (or IValidatableObject) to have the bound config validated at bind time. Failures throw EnvValidationException. See the binding readme.

Typed accessors

The IEnvReader interface provides typed accessors for a collection of environment variables. These come in four patterns:

• Get*(key): throws EnvException on missing or unparseable.
• Get*(key, default): returns default on missing; throws on unparseable.
• GetOptional*(key): returns null on missing; throws on unparseable.
• TryGet*(key, out value): returns false on missing or unparseable.

EnvCollection (Enver.InMemory), Environment.Variables (Enver.SystemEnvironment), and configuration.AsEnvReader() (Enver.Extensions.Configuration) all expose this interface.

Enver.InMemory

using System.Net;
using Enver;

var values = EnvCollection.From(DotEnvPaths.AppDirectory());

string dbHost     = values.GetString("DB_HOST");
int    port       = values.GetInt32("DB_PORT", 5432);    // default if missing; 0x/0b prefixes supported
bool   debug      = values.GetBoolean("DEBUG", false);   // default if missing; strict true/false
Uri    apiUrl     = values.GetUri("API_URL");
IPAddress bindIp  = values.Get<IPAddress>("BIND_ADDRESS");

Enver.SystemEnvironment

using System.Net;
using Enver;

string dbHost     = Environment.Variables.GetString("DB_HOST");
int    port       = Environment.Variables.GetInt32("DB_PORT", 5432);    // default if missing; 0x/0b prefixes supported
bool   debug      = Environment.Variables.GetBoolean("DEBUG", false);   // default if missing; strict true/false
Uri    apiUrl     = Environment.Variables.GetUri("API_URL");
IPAddress bindIp  = Environment.Variables.Get<IPAddress>("BIND_ADDRESS");

Enver.Extensions.Configuration

using System.Net;
using Enver.Extensions.Configuration;

var builder = WebApplication.CreateBuilder(args);

var configuration = builder.Configuration.AsEnvReader();

string dbHost     = configuration.GetString("DB_HOST");
int    port       = configuration.GetInt32("DB_PORT", 5432);    // default if missing; 0x/0b prefixes supported
bool   debug      = configuration.GetBoolean("DEBUG", false);   // default if missing; strict true/false
Uri    apiUrl     = configuration.GetUri("API_URL");
IPAddress bindIp  = configuration.Get<IPAddress>("BIND_ADDRESS");

Supported types

Type	Methods	Notes
string	GetString / GetOptionalString / TryGetString
bool	GetBoolean / GetOptionalBoolean / TryGetBoolean	true / false (case-insensitive)
int	GetInt32 / GetOptionalInt32 / TryGetInt32	Honors 0x / 0b prefixes
long	GetInt64 / GetOptionalInt64 / TryGetInt64	Honors 0x / 0b prefixes
double	GetDouble / GetOptionalDouble / TryGetDouble
Guid	GetGuid / GetOptionalGuid / TryGetGuid
Uri	GetUri / GetOptionalUri / TryGetUri	UriKind parameter (defaults to Absolute)
Version	GetVersion / GetOptionalVersion / TryGetVersion
any enum	GetEnum<T> / GetOptionalEnum<T> / TryGetEnum<T>	Rejects raw numeric values that don't correspond to a declared member
any IParsable<T>	Get<T> / GetOptional<T> / GetOptionalRef<T> / TryGet<T> / TryGetRef<T>	Covers DateTime, DateTimeOffset, DateOnly, TimeOnly, TimeSpan, IPAddress, IPNetwork, char, etc.
any INumberBase<T>	GetNumber<T> / GetOptionalNumber<T> / TryGetNumber<T>	Covers byte, sbyte, short, ushort, uint, ulong, decimal, float, Half, etc. Honors 0x / 0b prefixes.

Every row also has a Get*(key, defaultValue) overload that returns the supplied default if the key is missing (parse failures still throw).

For custom env sources, implement IEnvReader's single TryGetValue method; the full typed surface then applies via extension methods.

Supported runtimes

net8.0, net9.0, net10.0.

The Environment.LoadDotEnv* extension-member call syntax requires C# 14. Earlier C# versions can call the same methods via EnvironmentExtensions.LoadDotEnv* directly.

License

MIT.