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Gin Web Framework

AsciiJSON

AsciiJSON serializes data to JSON but escapes all non-ASCII characters into \uXXXX Unicode escape sequences. HTML-special characters like < and > are also escaped. The result is a response body that contains only 7-bit ASCII characters.

When to use AsciiJSON:

  • Your API consumers require strictly ASCII-safe responses (for example, systems that cannot handle UTF-8 encoded bytes).
  • You need to embed JSON inside contexts that only support ASCII, such as certain logging systems or legacy transports.
  • You want to ensure that characters like <, >, and & are escaped to avoid injection issues when JSON is embedded in HTML.

For most modern APIs, standard c.JSON() is sufficient since it outputs valid UTF-8. Use AsciiJSON only when ASCII safety is a specific requirement.

package main


import (
  "net/http"


  "github.com/gin-gonic/gin"
)


func main() {
  router := gin.Default()


  router.GET("/someJSON", func(c *gin.Context) {
    data := map[string]interface{}{
      "lang": "GO语言",
      "tag":  "<br>",
    }


    // will output : {"lang":"GO\u8bed\u8a00","tag":"\u003cbr\u003e"}
    c.AsciiJSON(http.StatusOK, data)
  })


  // Listen and serve on 0.0.0.0:8080
  router.Run(":8080")
}

You can test this endpoint with curl:

Terminal window
curl http://localhost:8080/someJSON
# Output: {"lang":"GO\u8bed\u8a00","tag":"\u003cbr\u003e"}

Notice that the Chinese characters 语言 are replaced with \u8bed\u8a00, and the <br> tag becomes \u003cbr\u003e. The response body is safe to consume in any ASCII-only environment.