Form Trigger "Redirect URL" does not map field values (e.g. appid) in latest n8n

[yangyang3]

Hi n8n team,

I have encountered a persistent issue with the Form Trigger node’s “Redirect URL” feature, even after upgrading to the latest version of n8n.

Problem Description:

• I created a form using the Form Trigger node, with fields named appid and secretkey.

• In the “Redirect URL” setting, I want to use the value entered by the user for appid, like this:

text

Apply to 授权应用.json

用户授权{{ appid }}&scope=xxxx

• However, after submitting the form, the redirect URL always has an empty value for appId, like:

text

Apply to 授权应用.json

…&appId=&scope=…

• I tried using both {{ appid }} and {{field-0}} in the expression. The editor highlights {{field-0}} in green (as if it’s recognized), but the value is still not mapped in the redirect URL after submission.

• The output JSON in the node shows the correct value for appid, but the redirect does not work.

What I have tried:

• Upgraded n8n to the latest version.

• Used both test and production form links.

• Cleared browser cache and tried different browsers.

• Tried different field names and variable expressions.

• The problem persists regardless of these attempts.

Screenshots:

(I have attached screenshots showing the form setup, the output JSON, and the resulting redirect URL.)

Expected behavior:

The value entered by the user for appid should be correctly mapped into the redirect URL after form submission.

Actual behavior:

The redirect URL always has an empty value for appId.

Additional notes:

• If I use a Webhook Trigger and a custom HTML form, I can map the variables and redirect as expected.

• This issue seems to be specific to the Form Trigger node’s redirect feature.

Request:

Please help investigate this issue. Is this a known bug? Is there any workaround for using dynamic field values in the Form Trigger’s redirect URL?

Thank you!

[zynate]

1. Use a full expression for the redirect URL (built-in support for partial mustache is not available):

• In the Form Trigger node’s Redirect URL field click “Expression”.
• Enter a single JavaScript expression, for example:

={{"https://yourapp.com/callback?appId=" + $json.appid + "&scope=xxxx"}}

• Make sure the entire value is inside that one ={{ … }} wrapper (no plain {{appid}} fragments).

2. If that still doesn’t work, handle the redirect yourself by:

• Removing the Redirect URL from the Form Trigger.
• Adding an HTTP Response (aka “Respond to Webhook”) node immediately after it.
• Configure the HTTP Response node as:
  • Response Code: 302
  • Header Location → set via expression:

https://yourapp.com/callback?appId={{$json.appid}}&scope=xxxx

• This will send a proper 302 redirect with your dynamic appid parameter.

Either approach will correctly inject the user’s appid into the URL at runtime.

[cutecatcode]

Hi @yangyang3, welcome to community.

What’s your purpose with the query params? Like url?data=appid&scope=x, also have you trying to use Form close node and pass the query params there?

Maybe this will help you.