topic Re: Custom Code Action Not Returning Output Fields — Workflow Shows Success but Output Is Empty in APIs & Integrations

Custom Code Action Not Returning Output Fields — Workflow Shows Success but Output Is Empty

GMaheshwari — Fri, 28 Nov 2025 07:00:18 GMT

Hi Community,

I’m facing an issue with a Custom Code Action inside a workflow.
The code executes successfully and the logs show success: true, but no output fields are returned to the workflow.

🔍 What’s happening

Custom code runs successfully
No errors reported
callback({ success: true, outputFields: {...} }) is executed
But in the workflow execution details:
- Output fields section is blank
- Downstream actions receive undefined
  🧪 Checked already
  - Output fields are properly defined in the action
  - Field names match exactly
  - Tried both formats:
    
    callback({ outputFields: { lineItemId: data.id } });
    and
    
    callback({ success: true, lineItemId: data.id });
  - Added debug logging → values are present in code
  - No timeouts
  - No exceptions
  - Tried multiple workflows — same issue
    🧵 Example log
    { success: true, lineItemId: "123456789" }
    
    But the workflow UI shows:
    Output Fields: empty
    Next action input: undefined
    ❓ Question
    Is this a known issue with Custom Code Actions not returning output fields?
    Is there any recent change to output handling in workflows?
    Would appreciate any guidance or confirmation.
    Thanks!

Re: Custom Code Action Not Returning Output Fields — Workflow Shows Success but Output Is Empty

BérangèreL — Fri, 28 Nov 2025 13:02:19 GMT

Hi @GMaheshwari, I hope you’re doing well!

Thank you for reaching out to the HubSpot Community!

Here are a couple of resources that might be helpful:

- Workflows | Custom Code Actions
- Automation API | Custom Workflow Actions

I’d also love to hear from our amazing Top Experts: Hi @HFisher7, @sylvain_tirreau and @BGrenon do you have any suggestions to help @GMaheshwari, please?

Thanks so much, and wishing you a fantastic weekend!
Bérangère

Re: Custom Code Action Not Returning Output Fields — Workflow Shows Success but Output Is Empty

RubenBurdin — Fri, 28 Nov 2025 17:47:44 GMT

Hi @GMaheshwari , this one is frustrating because everything “looks green” in the logs while the workflow shows nothing.

A couple of quirks to double-check. First, HubSpot only persists values that are nested under outputFields and whose keys exactly match the internal names you defined in the action config. The canonical pattern is callback({ outputFields: { line_item_id: data.id } }); and nothing else at the top level.

Extra keys like success: true are simply ignored by the workflow engine, even though they show up in logs (https://developers.hubspot.com/docs/api-reference/automation-actions-v4-v4/custom-code-actions )

Also make sure the output field type matches the value you’re returning: if the field is a number and you send a string, HubSpot quietly drops it instead of casting. Second, confirm you’re defining the outputs on that specific custom code action, not on a different revision or cloned action, and that you’re using the internal names (usually snake_case) in the callback.

A quick litmus test is to strip the code down to a minimal snippet that hardcodes a value, run “Test action,” and see if it appears. If even that doesn’t populate the Output fields section, it’s likely a platform-side issue and worth opening a ticket with the workflow run link and timestamp. When this custom code’s main job is just shuttling IDs between HubSpot and another system, Stacksync can handle that two-way sync layer so your workflows only read clean properties instead of wrestling with callback edge cases.

topic Re: Custom Code Action Not Returning Output Fields — Workflow Shows Success but Output Is Empty in APIs & Integrations

Custom Code Action Not Returning Output Fields — Workflow Shows Success but Output Is Empty

🔍 What’s happening

🧪 Checked already

🧵 Example log

❓ Question

Re: Custom Code Action Not Returning Output Fields — Workflow Shows Success but Output Is Empty

Re: Custom Code Action Not Returning Output Fields — Workflow Shows Success but Output Is Empty