> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/upstash/redis-js/llms.txt
> Use this file to discover all available pages before exploring further.

# JSON.SET

> Set JSON values in Redis

Sets the JSON value at the specified path in the key. Creates the key if it doesn't exist.

## Usage

```typescript theme={null}
await redis.json.set("user:123", "$", { name: "Alice", age: 30 });
```

## Arguments

<ParamField path="key" type="string" required>
  The key to store the JSON document
</ParamField>

<ParamField path="path" type="string" required>
  JSONPath expression specifying where to set the value in the JSON document. Use `$` to set the entire document.
</ParamField>

<ParamField path="value" type="TData" required>
  The JSON value to set. Can be a number, string, boolean, object, or array.
</ParamField>

<ParamField path="opts" type="object">
  Optional conditional set options

  <Expandable title="properties">
    <ParamField path="nx" type="boolean">
      Only set if the path does not exist. Cannot be used with `xx`.
    </ParamField>

    <ParamField path="xx" type="boolean">
      Only set if the path already exists. Cannot be used with `nx`.
    </ParamField>
  </Expandable>
</ParamField>

## Response

<ResponseField name="result" type="'OK' | null">
  Returns `"OK"` if the value was set successfully, or `null` if the condition (NX/XX) was not met.
</ResponseField>

## Examples

### Set entire JSON document

```typescript theme={null}
interface User {
  name: string;
  email: string;
  age: number;
  tags: string[];
}

const user: User = {
  name: "Alice",
  email: "alice@example.com",
  age: 30,
  tags: ["developer", "admin"]
};

await redis.json.set("user:123", "$", user);
// "OK"
```

### Set specific field

```typescript theme={null}
await redis.json.set("user:123", "$.age", 31);
// "OK"
```

### Set nested value

```typescript theme={null}
await redis.json.set("user:123", "$.address.city", "New York");
```

### Set array element

```typescript theme={null}
await redis.json.set("user:123", "$.tags[0]", "senior-developer");
```

### Conditional set - only if path doesn't exist (NX)

```typescript theme={null}
const result = await redis.json.set(
  "user:123",
  "$.premium",
  true,
  { nx: true }
);

if (result === "OK") {
  console.log("Premium flag added");
} else {
  console.log("Premium flag already exists");
}
```

### Conditional set - only if path exists (XX)

```typescript theme={null}
const result = await redis.json.set(
  "user:123",
  "$.age",
  32,
  { xx: true }
);

if (result === "OK") {
  console.log("Age updated");
} else {
  console.log("Age field doesn't exist");
}
```

## JSONPath Syntax

* `$` - Root element (sets entire document)
* `$.field` - Set a specific field
* `$.field[0]` - Set array element at index
* `$.nested.field` - Set nested field

## See Also

* [JSON.GET](/api/commands/json-get) - Get JSON values
* [JSON.DEL](/api/commands/json-del) - Delete JSON values
* [Redis JSON.SET documentation](https://redis.io/commands/json.set)