# Template strings in subflow args

**URL:** <https://discourse.nodered.org/t/template-strings-in-subflow-args/100445>\
**Category:** General\
**Created:** [24 February 2026 14:59 UTC](https://discourse.nodered.org/t/template-strings-in-subflow-args/100445 "2026-02-24T14:59:49Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![ThingsTinkerer](https://avatars.discourse-cdn.com/v4/letter/t/91b2a8/32.png) [@ThingsTinkerer](https://discourse.nodered.org/u/ThingsTinkerer)\
**Post date:** [24 February 2026 14:59 UTC](https://discourse.nodered.org/t/template-strings-in-subflow-args/100445/1 "2026-02-24T14:59:49Z")

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Learned the hard way I need to environmentalize url in node red today. I have a lot of http subflows which take URL string arg. Is it possible to mix in env vars here? For example `${MY_URL}/api/auth/login`. This is a piece of cake in js, hopefully easy in nr too?

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**Author:** ![ThingsTinkerer](https://avatars.discourse-cdn.com/v4/letter/t/91b2a8/32.png) [@ThingsTinkerer](https://discourse.nodered.org/u/ThingsTinkerer)\
**Post date:** [24 February 2026 15:02 UTC](https://discourse.nodered.org/t/template-strings-in-subflow-args/100445/2 "2026-02-24T15:02:47Z")

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I guess one way is to do manual string replacements inside subflow.

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [24 February 2026 15:05 UTC](https://discourse.nodered.org/t/template-strings-in-subflow-args/100445/3 "2026-02-24T15:05:43Z")

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Yes if you use the `$` option, you can

> **[Using environment variables : Node-RED](https://nodered.org/docs/user-guide/environment-variables)**

> - if `${}` is present, it will substitute the corresponding environment variable into the result: For example, given the value `"Hello ${FOO}"` and the env var `FOO` is set to `World`, this results in the value `"Hello World"`

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<div class="post-metadata">

**Author:** ![ThingsTinkerer](https://avatars.discourse-cdn.com/v4/letter/t/91b2a8/32.png) [@ThingsTinkerer](https://discourse.nodered.org/u/ThingsTinkerer)\
**Post date:** [24 February 2026 17:02 UTC](https://discourse.nodered.org/t/template-strings-in-subflow-args/100445/4 "2026-02-24T17:02:57Z")

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Fantastic! Onto further improvements 😃 Had a case today where an url went down, and without env variable it was too much hassle to change url everywhere. But next time, it will be a breeze.

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [10 March 2026 17:03 UTC](https://discourse.nodered.org/t/template-strings-in-subflow-args/100445/5 "2026-03-10T17:03:31Z")

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