How can I configure ASP.NET Core Web API controller to return pretty formatted JSON content for the Development environment only?
By default, it returns something like:
{"id":1,"code":"4315"} I would like to have indents in the response for readability:
{ "id": 1, "code": "4315" } .NET Core 2.2 and lower:
In your Startup.cs file, call the AddJsonOptions extension:
services.AddMvc() .AddJsonOptions(options => { options.SerializerSettings.Formatting = Formatting.Indented; }); Note that this solution requires Newtonsoft.Json.
.NET Core 3.0 and higher:
In your Startup.cs file, call the AddJsonOptions extension:
services.AddMvc() .AddJsonOptions(options => { options.JsonSerializerOptions.WriteIndented = true; }); As for switching the option based on environment, this answer should help.
SerializerSettings is in Microsoft.AspNetCore.Mvc, but in order to use Formatting you need a using Newtonsoft.Json.
options.SerializerSettings.Formatting = Newtonsoft.Json.Formatting.Indented;
If you want to turn on this option for a single controller instead of for all JSON, you can have your controller return a JsonResult and pass the Formatting.Indented when constructing the JsonResult like this:
return new JsonResult(myResponseObject) { SerializerSettings = new JsonSerializerSettings() { Formatting = Formatting.Indented } }; In .NET Core 3 (and later), you can achieve this as follows:
services.AddMvc() .AddJsonOptions(options => { options.JsonSerializerOptions.WriteIndented = true; }); In my project, I used Microsoft.AspNetCore.Mvc with the code below for all controllers. This for .NET Core 3.
public void ConfigureServices(IServiceCollection services) { services.AddControllers() .AddNewtonsoftJson(options => { options.SerializerSettings.Formatting = Formatting.Indented; }); } In .NET 7, if you want to return indented JSON output and you are using controllers, you can use this in your startup code:
builder.Services.AddControllers() .AddJsonOptions(options => { options.JsonSerializerOptions.WriteIndented = true; }); This is using the built-in JSON capabilities in .NET, not using any external frameworks like Newtonsoft.
If you want this option only for specific action, using System.Text.Json
return new JsonResult(myResponseObject) { SerializerSettings = new JsonSerializerOptions() { WriteIndented = true } }; 