How do you implement a loop in a Salesforce Flow?

Posted by Vinay Vernekar 23rd October 2025

When and why to use a Loop in Salesforce Flow

Use a Loop when you need to iterate over a collection of records or items (for example, a list of Contacts, Opportunities or custom objects) and perform logic or transformations on each item. Loops let you process items one-by-one inside the Flow canvas while keeping the operation bulk-safe by collecting changes and then performing a single DML operation.

High-level pattern

Typical pattern for using a Loop in a record-triggered or autolaunched Flow:

  • Get Records (populate a collection)
  • Loop over the collection
  • Inside Loop: use Assignment and Decision elements to evaluate and change each item
  • Assignment: add modified items to a separate collection for updates
  • After Loop: Update Records (single bulk DML using the collected items)

Step-by-step example: Update a Contact field for a set of Contacts

Goal: For all Contacts related to an Account, set a checkbox Needs_Follow_Up__c to true if their LastActivityDate is more than 90 days old.

Flow elements and variables you’ll use:

  • collectionContacts (Record Collection) — result of Get Records
  • singleContact (Record) — current item in Loop
  • contactsToUpdate (Record Collection) — accumulates modified contacts
  • Loop element that iterates over collectionContacts
  • Decision element inside loop to check LastActivityDate
  • Assignment element to set the field and add to contactsToUpdate
  • Update Records element after the loop to update contactsToUpdate

Pseudo-configuration


// Get Records
Get Records: contact where AccountId = {!record.Id} (store all records in collectionContacts)

// Loop
Loop: for each {!singleContact} in {!collectionContacts}
Decision: is LASTACTIVITYDATE <= TODAY() - 90 ? True: Assignment: set {!singleContact}.Needs_Follow_Up__c = True Assignment: add {!singleContact} to {!contactsToUpdate} False: (do nothing) End Loop// After loop Update Records: Update {!contactsToUpdate}

Best practices and tips

  • Always operate on collections and perform DML once after the loop to avoid governor limits (do not update inside the loop).
  • Prefer autolaunched Flow for scheduled bulk processing or record-triggered Flow when reacting to record changes.
  • Initialize collection variables before the loop (Assignment to a new empty collection) to avoid null reference issues.
  • Be careful with loops that may iterate thousands of records — add limits in your Get Records or use Scheduled Batch flows.
  • When you need parallel processing or callouts, consider using subflows or Apex for complex/long-running work.
  • Use Fault paths on Get/Update elements to log or handle errors gracefully.

Common mistakes

  • Performing Update Records inside the loop — causes excessive DML and governor limit errors.
  • Not initializing collections — leads to null pointer issues when adding items.
  • Using a Flow-Built loop for very large datasets — better to use Batchable Apex or split into smaller scheduled batches.

Conclusion

Loops in Salesforce Flow are powerful for iterating collections and performing item-level logic. Follow the standard pattern (Get Records → Loop → Assign/Collect → Update Records) to keep Flows efficient and governor-limit friendly. For more complex scenarios, combine subflows, scheduled runs, or Apex to maintain performance and reliability.