FormSG (Multi-Respondent Form) integration
Advanced Feature
This guide covers Plumber's integration with FormSG Multi-Respondent Forms. Before proceeding, you should:
Be comfortable using Plumber to create basic pipes
Understand how Multi-Respondent Forms work in FormSG
Have already set up and tested an MRF workflow in FormSG
If you're new to MRF, we recommend reading FormSG's guide on Multi-Respondent Forms first to understand workflow steps, approval fields, and respondent routing.
What is Multi-Respondent Forms?
Multi-Respondent Forms (MRF) is a FormSG feature that allows multiple people to fill out different parts of the same form in sequence. For example, an employee submits a leave request, then their manager reviews and approves it, then HR processes it, all within a single form submission.
MRF Integration with Plumber
When you connect an MRF form to Plumber, you can automate actions at each step of the approval process:
Send notifications when someone submits or approves
Update spreadsheets with the latest status
Trigger different actions based on approval or rejection
Requirements Before you start, make sure you have:
A Multirespondent FormSG form
Workflow steps configured in FormSG (who fills out what, in what order)
The form must be published
How to Connect Your MRF Form
Click "Choose how you want your workflow to start"
Select "FormSG"
Click "Choose connection" and add new form
Enter your MultiRespondent form URL and secret key
Click "Connect"
Plumber will detect that your form is a Multirespondent form
Adding action to each step
MRF forms don't always require approvers, but the example in this guide will include approval steps
Now you can add actions after each workflow step. Click the + button after any step to add an action. In this example, there are two other approvers in this workflow.
Understanding Approval Branches
When you add an approval step to your workflow, you can set up two different paths depending on the outcome:
Each approval step shows two tabs:
Setting Up Your Branches
Click on the If approved tab
Add the actions you want to happen when approved
Click on the If rejected tab
Add the actions you want to happen when rejected


"If Rejected" is currently selected, the Third Submission step is greyed out and will not run. The automation is essentially blocked at Step 2, nothing downstream will trigger until the rejection is handled or the flow is redesigned.
If approved
Actions that run when someone approves the request
If rejected
Actions that run when someone rejects the request
Example
Imagine you're building a leave request workflow that involves approval from both team lead and manager:
If approved:
Send an email to employee that team has approved
Send a confirmation email to the employee
Notify HR via email

If rejected:
Send a rejection email with the reason

Tips & Good to Know
Updating step names: Step names are pulled from FormSG. To rename a step, update it in your FormSG workflow settings, then click "Test step" in Plumber to sync the new name.
MRF steps can only be managed in FormSG. You cannot reorder, create, delete, or edit them in Plumber. After making changes in FormSG, click "Test step" in Plumber to sync.
You can, however, freely reorder action steps within or across MRF steps and branches.
What Happens When MRF Steps Change
Deleting an MRF step in FormSG: After syncing via "Test step", all action steps between the deleted step and the next MRF step will also be removed from Plumber.
Adding a new MRF step in FormSG: The new step appears after the last existing MRF step. If the previous last step had a rejection branch that the new step doesn't, the rejection branch will be removed.
Limitations
For-Each and If-Then steps can only be added in the last MRF step, one per branch in approval branches.
Delay and Only Continue If cannot be placed immediately before an MRF step. It will not work as intended.
Reconnecting your pipe to a non-MRF form will wipe your entire pipe configuration.
Common errors when using MRF integration
MRF steps didn't appear after testing
Make sure your form is set to Multirespondent mode in FormSG
Check that you have workflow steps configured in FormSG
Make sure the form is published
Try clicking Test step again
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