# Add json object

**URL:** <https://discuss.elastic.co/t/add-json-object/289682>\
**Category:** Logstash\
**Created:** [November 19, 2021, 12:11pm UTC](https://discuss.elastic.co/t/add-json-object/289682 "2021-11-19T12:11:37Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Roberto\_B](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/roberto_b/32/77615_2.png) [@Roberto\_B](https://discuss.elastic.co/u/Roberto_B)\
**Post date:** [November 19, 2021, 12:11pm UTC](https://discuss.elastic.co/t/add-json-object/289682/1 "2021-11-19T12:11:37Z")

</div>

Hi there,

I would like to add a field liek this:

```auto
field : {sub1 : null}

```

which is the best way to do that?

Kind Regards

Roberto

---

<div class="post-metadata">

**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [November 19, 2021, 6:08pm UTC](https://discuss.elastic.co/t/add-json-object/289682/2 "2021-11-19T18:08:15Z")

</div>

You could try either

```
    mutate { add_field => { "[@metadata][json]" => '{ "sub1": null }' } }
    json { source => "[@metadata][json]" target => "field" }

```

or

```
ruby { code => 'event.set("[field][sub1]", nil)' }

```

Both will result in

```
     "field" => {
    "sub1" => nil
},
```

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [December 17, 2021, 6:08pm UTC](https://discuss.elastic.co/t/add-json-object/289682/3 "2021-12-17T18:08:17Z")

</div>

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