# Source: https://upstash.com/docs/redis/sdks/ts/commands/hash/hsetnx.md

# Source: https://upstash.com/docs/redis/sdks/py/commands/hash/hsetnx.md

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

# HSETNX

> Write a field to a hash but only if the field does not exist.

## Arguments

<ParamField body="key" type="str" required>
  The key of the hash.
</ParamField>

<ParamField body="field" type="str" required>
  The name of the field.
</ParamField>

<ParamField body="value" type="Any" required>
  The value to set.
</ParamField>

## Response

<ResponseField type="bool" required>
  `True` if the field was set, `False` if it already existed.
</ResponseField>

<RequestExample>
  ```py Example theme={"system"}
  assert redis.hsetnx("myhash", "field1", "Hello") == True
  assert redis.hsetnx("myhash", "field1", "World") == False
  ```
</RequestExample>