# Buffer and env variable

**URL:** <https://discourse.nodered.org/t/buffer-and-env-variable/6252>\
**Category:** General\
**Created:** [31 December 2018 06:51 UTC](https://discourse.nodered.org/t/buffer-and-env-variable/6252 "2018-12-31T06:51:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Rahul\_Mathavan](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/rahul_mathavan/32/4550_2.png) [@Rahul\_Mathavan](https://discourse.nodered.org/u/Rahul_Mathavan)\
**Post date:** [31 December 2018 06:51 UTC](https://discourse.nodered.org/t/buffer-and-env-variable/6252/1 "2018-12-31T06:51:14Z")

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What is the use of buffer and env variable in the inject node,where can I use them

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<div class="post-metadata">

**Author:** ![knolleary](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/knolleary/32/3_2.png) [@knolleary](https://discourse.nodered.org/u/knolleary)\
**Post date:** [31 December 2018 09:36 UTC](https://discourse.nodered.org/t/buffer-and-env-variable/6252/2 "2018-12-31T09:36:23Z")

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They are other types of data you can inject into the flow.

The Buffer type let's you inject a node.js Buffer object - typically used to inject binary data.

The Env type let's you inject the value of an environment variable.

It's up to you when to use them, and whether you have a particular need for them. The Env var option can be useful where you run the same flow on multiple devices and want to customise some value per-device without having to change the flow.