---
acl_categories:
- '@json'
- '@write'
- '@slow'
arguments:
- name: key
  type: key
- name: path
  type: string
- name: value
  type: string
categories:
- docs
- develop
- stack
- oss
- rs
- rc
- oss
- kubernetes
- clients
complexity: O(M+N) when path is evaluated to a single value where M is the size of
  the original value (if it exists) and N is the size of the new value, O(M+N) when
  path is evaluated to multiple values where M is the size of the key and N is the
  size of the new value * the number of original values in the key
description: Merges a given JSON value into matching paths. Consequently, JSON values
  at matching paths are updated, deleted, or expanded with new children
group: json
hidden: false
linkTitle: JSON.MERGE
module: JSON
railroad_diagram: /images/railroad/json.merge.svg
since: 2.6.0
stack_path: docs/data-types/json
summary: Merges a given JSON value into matching paths. Consequently, JSON values
  at matching paths are updated, deleted, or expanded with new children
syntax_fmt: JSON.MERGE key path value
title: JSON.MERGE
---
Merge a given JSON value into matching paths. Consequently, JSON values at matching paths are updated, deleted, or expanded with new children.

This command complies with [RFC7396](https://datatracker.ietf.org/doc/html/rfc7396) Json Merge Patch

[Examples](#examples)

## Required arguments

<details open><summary><code>key</code></summary>

is the key to merge into.
</details>

<details open><summary><code>path</code></summary>

specifies the JSONPath. For non-existing keys the `path` must be `$`. For existing keys, for each matched `path`, the value that matches the `path` is merged with the JSON `value`. For existing keys, when the path exists, except for the last element, a new child is added with the JSON `value`.

</details>

<details open><summary><code>value</code></summary>

is the JSON value to merge with at the specified path. Merging is done according to the following rules per JSON value in the `value` argument while considering the corresponding original value if it exists:
*   merging an existing object key with a `null` value deletes the key
*   merging an existing object key with non-null value updates the value
*   merging a non-existing object key adds the key and value
*   merging an existing array with any merged value, replaces the entire array with the value
</details>

## Examples

JSON.MERGE provides four different behaviors to merge changes on a given key: create a non-existent path, update an existing path with a new value, delete an existing path, or replace an array with a new array

<details open>
<summary><b>Create a non-existent path-value</b></summary>

{{< highlight bash >}}
redis> JSON.SET doc $ '{"a":2}'
OK
redis> JSON.MERGE doc $.b '8'
OK
redis> JSON.GET doc $
"[{\"a\":2,\"b\":8}]"
{{< / highlight >}}

</details>

<details open>
<summary><b>Replace an existing value</b></summary>

{{< highlight bash >}}
redis> JSON.SET doc $ '{"a":2}'
OK
redis> JSON.MERGE doc $.a '3'
OK
redis> JSON.GET doc $
"[{\"a\":3}]"
{{< / highlight >}}

</details>

<details open>
<summary><b>Delete an existing value</b></summary>

{{< highlight bash >}}
redis> JSON.SET doc $ '{"a":2}'
OK
redis> JSON.MERGE doc $ '{"a":null}'
OK
redis> JSON.GET doc $
"[{}]"
{{< / highlight >}}

</details>

<details open>
<summary><b>Replace an Array</b></summary>

{{< highlight bash >}}
redis> JSON.SET doc $ '{"a":[2,4,6,8]}'
OK
redis> JSON.MERGE doc $.a '[10,12]'
OK
redis> JSON.GET doc $
"[{\"a\":[10,12]}]"
{{< / highlight >}}

</details>

<details open>
<summary><b>Merge changes in multi-paths</b></summary>

{{< highlight bash >}}
redis> JSON.SET doc $ '{"f1": {"a":1}, "f2":{"a":2}}'
OK
redis> JSON.GET doc
"{\"f1\":{\"a\":1},\"f2\":{\"a\":2}}"
redis> JSON.MERGE doc $ '{"f1": null, "f2":{"a":3, "b":4}, "f3":[2,4,6]}'
OK
redis> JSON.GET doc
"{\"f2\":{\"a\":3,\"b\":4},\"f3\":[2,4,6]}"
{{< / highlight >}}

</details>

## Redis Software and Redis Cloud compatibility

| Redis<br />Software | Redis<br />Cloud | <span style="min-width: 9em; display: table-cell">Notes</span> |
|:----------------------|:-----------------|:------|
| <span title="Not supported">&#x274c; Standard</span><br /><span title="Not supported"><nobr>&#x274c; Active-Active</nobr></span> | <span title="Not supported">&#x274c; Standard</span><br /><span title="Not supported"><nobr>&#x274c; Active-Active</nobr></span> |  |

## Return information

{{< multitabs id="json-merge-return-info"
    tab1="RESP2"
    tab2="RESP3" >}}

One of the following:
* [Simple string reply]({{< relref "/develop/reference/protocol-spec#simple-strings" >}}): `OK` if executed correctly.
* [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}): if the operation fails to set the new values.

-tab-sep-

One of the following:
* [Simple string reply]({{< relref "/develop/reference/protocol-spec#simple-strings" >}}): `OK` if executed correctly.
* [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}): if the operation fails to set the new values.

{{< /multitabs >}}

## See also

[`JSON.GET`]({{< relref "commands/json.get/" >}}) | [`JSON.MGET`]({{< relref "commands/json.mget/" >}}) | [`JSON.SET`]({{< relref "commands/json.set/" >}}) | [`JSON.MSET`]({{< relref "commands/json.mset/" >}})

## Related topics

* [RedisJSON]({{< relref "/develop/data-types/json/" >}})
* [Index and search JSON documents]({{< relref "/develop/ai/search-and-query/indexing/" >}})