Formatting datetime in asp net core 3 0 using system text json


Formatting datetime in ASP.NET Core 3.0 using System.Text.Json can be a common requirement in web development. In this article, we will explore how to achieve this with examples.

Formatting DateTime

ASP.NET Core 3.0 provides the System.Text.Json for JSON and deserialization. To format DateTime values, we can use the JsonSerializerOptions class and its , Converters.

Let's consider an example where we have a DateTime that needs to be formatted as a in a specific format.

using System;
using System.Text.Json;

public class Program
    public static void Main()
        DateTime dateTime = DateTime.Now;
        JsonSerializerOptions options = new JsonSerializerOptions();
        options.Converters.Add(new DateTimeConverter("yyyy-MM-dd HH:mm:ss"));
        string formattedDateTime = JsonSerializer.Serialize(dateTime, options);

public class DateTimeConverter : System.Text.Json.Serialization.
    private readonly string format;

    public DateTimeConverter(string format)
        this.format = format;

    public override DateTime Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        throw new NotImplementedException();

    public override void Write(Utf8JsonWriter writer, DateTime value, JsonSerializerOptions options)

In the above example, we create a DateTimeConverter class that from the JsonConverter class provided by System.Text.Json. This class allows us to customize the serialization and deserialization of DateTime .

We override the Write method to format the DateTime value using the format. In this case, we use the “yyyy-MM-dd HH:mm:ss” format.

Next, we create an of the DateTimeConverter class and add it to the Converters property of the JsonSerializerOptions class. This ensures that the DateTime value will be formatted according to our custom converter.

Finally, we use the JsonSerializer.Serialize method to convert the DateTime object to a JSON string, passing the options object as a parameter. The formatted DateTime string is then printed to the console.


Formatting DateTime values in ASP.NET Core 3.0 using System.Text.Json is straightforward. By creating a custom converter and adding it to the JsonSerializerOptions, we can easily format DateTime objects according to our requirements.

Remember to adjust the format string in the DateTimeConverter class to match your desired format. This allows you to have full control over how DateTime values are serialized to JSON strings.

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