Strongly Typed JSON Keys

Strongly Typed JSON Keys is a .NET Roslyn source generator that reads JSON files at build time and generates static classes containing const string fields for each JSON key (including nested).

The goal is to eliminate hard-coded string keys when working with JSON-based data such as configuration files, localization resources, or structured payloads.

Why use this?

Hard-coding JSON keys as strings can lead to:

• Typos that only fail at runtime;
• Painful refactors when keys change;
• Poor discoverability and IntelliSense support.

This source generator solves those problems by:

• Generating compile-time constants for JSON keys;
• Making key usage refactor-safe;
• Providing IntelliSense and compile-time checking.

What it does

Given one or more JSON files, the generator:

• Parses their keys at compile time;
• Generates static classes with const string fields each containing the full key path;
• Keeps your code in sync with your JSON structure.

How do I use it

Just include your JSON files in your project as AdditionalFiles like this:

<!-- ExampleProject.csproj -->

  <ItemGroup>
    <AdditionalFiles Include="json_files/example.json">
      <GenerateKeys>true</GenerateKeys>
      <ClassName>ExampleKeys</ClassName>
    </AdditionalFiles>
  </ItemGroup>

The GenerateKeys tag is required for the generator to process your JSON files.

Options

You can configure the generation of each file to your liking with these options:

Name	Description	Type
RootKeyPath	Limits key generation to a nested JSON object instead of the entire file.	string
KeysPrefix	Prefixes all generated keys with a specified value.	string
ClassName	The name of the generated class. Defaults to the JSON file name.	string
CapitalizeGeneratedKeys	Capitalizes generated field names to avoid conflicts with C# keywords.	bool

License: MIT