Command: JSON.SET

Overview

The JSON.SET command allows clients to store structured JSON objects under a specific key in a distributed, in-memory data store. If the key already exists, the stored JSON value is overwritten. This is particularly useful for schema-less data use cases like storing user profiles, configurations, and nested records.

Command Name

JSON.SET

Description

Stores a valid JSON object at the specified key. If the key already exists, its previous value is replaced. The value must be a valid JSON object (e.g., not a number, string, or array as the top-level structure). This supports flexible, nested data models and is typically used for structured configurations, user metadata, and document storage.

Use Cases

  • Store user profile data:

      {"name": "Alice", "age": 27}

  • Save application settings:

      {"theme": "dark", "notifications": {"email": true, "sms": false}}

  • Manage nested business objects or configuration trees.

Syntax 

  JSON.SET <key> <json_value>

  • <key> : String identifier under which the JSON object is stored.

  • <json_value> : A stringified JSON object (must be valid JSON). The top-level structure must be an object ( {} ).

Permissions

  • Write Access Required: The user/client must have write access to the targeted key’s shard.

  • Internally WAL (Write-Ahead Log) records the command for durability and persistence.

Examples

Basic JSON Set 
  localhost:9219> JSON.SET myObj '{"name":"John","age":30,"hobbies":["reading","hiking"]}'
Ok
Retrieve It 
  localhost:9219> JSON.GET myObj
  
  Ok {
  "age": 30,
  "hobbies": [
    "reading",
    "hiking"
  ],
  "name": "John"
}
Update with Nested Object 
  localhost:9219> JSON.SET myObj '{"name":"John Doe","age":30,"isActive":true,"hobbies":["reading","hiking"],"address":{"street":"123 Main St","city":"New York"}}'
Ok
  
  localhost:9219> JSON.GET myObj
  
  Ok {
  "address": {
    "city": "New York",
    "street": "123 Main St"
  },
  "age": 30,
  "hobbies": [
    "reading",
    "hiking"
  ],
  "isActive": true,
  "name": "John Doe"
}

Behavior on Error

Condition Error Message
Missing key or value InvalidKeyError: Key must be provided
Incorrect number of arguments InvalidArgsError: invalid number of arguments, Syntax: LIST.FILTER <key> <path>
Invalid JSON value InvalidValueError: provided value not a valid json object