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Validate data: check first, then process

6 steps± 4 minVideoVerified 22 Oct 2026
  1. Step 1 · Open Flow and create a workflow
  2. Step 2 · A request with a mistake
  3. Step 3 · Write the rules
  4. Step 4 · Two ways
  5. Step 5 · Put the steps in one line and save
  6. Step 6 · Run

Validate data comes from a plugin: an extension your administrator adds to Flow, and that sits in the library like any other step. You write per field which type it must have. If everything is right, the workflow continues through the top exit; if something is missing or a type is wrong, through the bottom one, with the errors attached.

Watch the whole guide as a video6 steps in one film
Step 1 / 6

Open Flow and create a workflow

In the portal, under Environments, click Development and there Open; Flow opens in a new tab. There, click ＋ next to General, choose New workflow and give it a name. A new workflow starts with an Event trigger: the point where it begins.

  1. Click Development
Open Flow and create a workflow · Click Development
  1. Click Open ↗
Open Flow and create a workflow · Click Open ↗
  1. Click Add to General
Open Flow and create a workflow · Click Add to General
  1. Click New workflow
Open Flow and create a workflow · Click New workflow
  1. In Workflow name, type Guide · check a request
Open Flow and create a workflow · In Workflow name, type Guide · check a request
Step 2 / 6

A request with a mistake

Put a request in the sample data where the amount was filled in as text: in real life you see that more often than you would think.

  1. Click the step ‘Event trigger’
A request with a mistake · Click the step ‘Event trigger’
  1. Click Code
A request with a mistake · Click Code
  1. In the sample data, type `{
A request with a mistake · In the sample data, type `{; ; ;
Step 3 / 6

Write the rules

Add Validate data. Under Rules (Code) you put the type per field: string (text), number, boolean, object or array (list). A field that is not there is an error too.

  1. Click Add node
Write the rules · Click Add node
  1. Click Validate data
Write the rules · Click Validate data
  1. In Name, type Check request
Write the rules · In Name, type Check request
  1. Click Code
Write the rules · Click Code
  1. In the rules, type `{
Write the rules · In the rules, type `{; ; ;
  1. Click the dot of ‘Event trigger’
Write the rules · Click the dot of ‘Event trigger’
  1. Click the dot of ‘Check request’
Write the rules · Click the dot of ‘Check request’
Step 4 / 6

Two ways

Add Transform data twice: Process for a good request, Send back for a wrong one, with the errors from {{validation.errors}}. Connect Yes (top) to Process and No (bottom) to Send back.

  1. Click Add node
Two ways · Click Add node
  1. Click Transform data
Two ways · Click Transform data
  1. In Name, type Process
Two ways · In Name, type Process
  1. Click Remove field
Two ways · Click Remove field
  1. Click Remove field
Two ways · Click Remove field
  1. In New field, type status
  2. In status, type in progress
Two ways · In New field, type status; In status, type in progress
  1. Click Transform data
Two ways · Click Transform data
  1. In Name, type Send back
Two ways · In Name, type Send back
  1. Click Remove field
Two ways · Click Remove field
  1. Click Remove field
Two ways · Click Remove field
  1. In New field, type status
  2. In status, type sent back
  3. In New field, type reason
  4. In reason, type {{validation.errors}}
Two ways · In New field, type status; In status, type sent back; In New field, type reason; In reason, type {{validation.errors}}
  1. Click exit Yes of ‘Check request’
Two ways · Click exit Yes of ‘Check request’
  1. Click the dot of ‘Process’
Two ways · Click the dot of ‘Process’
  1. Click exit No of ‘Check request’
Two ways · Click exit No of ‘Check request’
  1. Click the dot of ‘Send back’
Two ways · Click the dot of ‘Send back’
Step 5 / 6

Put the steps in one line and save

Select the steps (click the first, and the others while holding Shift) and click Align horizontally: they then stand in one line and you read the workflow from left to right; a branch (such as No of an If / Else) gets its own row below. Fit to view puts everything in sight; then Save.

  1. Click ‘Event trigger’
Put the steps in one line and save · Click ‘Event trigger’
  1. Click ‘Check request’ while holding Shift
Put the steps in one line and save · Click ‘Check request’ while holding Shift
  1. Click ‘Process’ while holding Shift
Put the steps in one line and save · Click ‘Process’ while holding Shift
  1. Click ‘Send back’ while holding Shift
Put the steps in one line and save · Click ‘Send back’ while holding Shift
  1. Click Align horizontally
Put the steps in one line and save · Click Align horizontally
  1. Click Fit to view
Put the steps in one line and save · Click Fit to view
  1. Click Save
Put the steps in one line and save · Click Save
Step 6 / 6

Run

The check found one error and the workflow went to Send back; under Data after the run is why: the amount must be a number. Flow knows what the step returns ({{validation.valid}} and {{validation.errors}}) while you build, so you can use it straight away.

  1. Click Run
Run · Click Run
Run · Status: Completed.
Run · 1 error found.
Run · status: sent back.

This guide was carried out step by step on 22 Oct 2026 by an automated test on Flow (version 3e563176).