You know, curl is a popular command-line tool which is used by many developers for testing REST APIs. However, curl doesn’t format API response containing JSON document, which makes it difficult to read and understand the JSON content. For example:

{"id":1,"firstName":"Bilbo","lastName":"Baggins","name":"Bilbo Baggins","role":"burglar","_links":{"self":{"href":"http://localhost:8080/employees/1"},"employees":{"href":"http://localhost:8080/employees"}}}

Surely you want to have the JSON content formatted nicely like the below, right?

{
  "id": 1,
  "firstName": "Bilbo",
  "lastName": "Baggins",
  "name": "Bilbo Baggins",
  "role": "burglar",
  "_links": {
    "self": {
      "href": "http://localhost:8080/employees/1"
    },
    "employees": {
      "href": "http://localhost:8080/employees"
    }
  }
}

In this quick post, I’m going to share with you how to prettify JSON with curl like that - making API testing using curl more convenient and easier.

Basically, to format JSON with curl, you need to use pipe syntax in command line as follows:

curl options URI | <another_tool>

Here, | is the pipe character, followed by another tool that processes the output given from curl.

 

1. How to prettify JSON with curl on Windows

On Windows, you can use jq or NodeJS’s json tool as JSON beautifier for curl.

Using jq:

jq is a lightweight and flexible command-line JSON processor. Visit this page to download its executable EXE file. You will have jq-win64.exe file. Copy it to C:\Windows\System32 and change the name to just jq.exe.

Now, in the command prompt you can type the following command to pretty print JSON output from curl:

curl localhost:8080/employees/1 | jq

The output will look like this:

 

Using NodeJS:

Download and install NodeJS from its official homepage. Then open a new command prompt, type the following:

npm install -g jsontool

This command will install JSON tool. Then you can pretty print JSON output from curl using the follow command:

curl localhost:8080/employees/1 | json

2. How to prettify JSON with curl on macOS

On macOS, you don’t have to install extra software as macOS comes with pre-installed tools that can format JSON, such as Python and json_pp. So in the terminal you just type:

curl localhost:8080/employees/1 | json_pp

or:

curl localhost:8080/employees/1 | python -m json.tool

That’s few tips you can use to prettify JSON output when testing REST APIs using curl. I hope you found this post helpful. Thanks for reading.

 

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