Loop

Iterate over a list of items, processing them one at a time or in batches. Similar to n8n’s SplitInBatches node.

Configuration

Output

Usage Examples

Process items one at a time

Iterate over database rows and send an email for each:

1. Database Query — SELECT * FROM users WHERE active = true
2. Loop — Items: {{DatabaseQuery.rows}}, Batch Size: 1
3. Send Email — To: {{Loop.currentItem.email}}

Process items in batches

Batch API calls to avoid rate limits:

1. HTTP Request — Fetch a list of records
2. Loop — Items: {{FetchRecords.data}}, Batch Size: 10
3. HTTP Request — Process {{Loop.currentBatch}} as a batch

How Iteration Works

The Loop node uses batch-based iteration:

1. The array is split into batches based on batchSize
2. Each batch iteration processes the next chunk of items
3. The hasMore flag indicates whether more batches remain
4. The workflow executor uses currentBatchIndex to track progress

For single-item iteration (batch size = 1), use {{Loop.currentItem}} to access the current item directly.

Generated Code

When exporting a workflow, the Loop action generates:

export async function loopStep(input: {
  items: unknown[];
  batchSize?: number;
  currentBatchIndex?: number;
}) {
  "use step";
 
  const items = Array.isArray(input.items) ? input.items : [];
  const batchSize = Math.max(1, input.batchSize || 1);
  const currentBatchIndex = input.currentBatchIndex ?? 0;
  const totalItems = items.length;
  const totalBatches = Math.ceil(totalItems / batchSize);
 
  const startIndex = currentBatchIndex * batchSize;
  const endIndex = Math.min(startIndex + batchSize, totalItems);
  const currentBatch = items.slice(startIndex, endIndex);
 
  return {
    hasMore: currentBatchIndex < totalBatches - 1,
    currentBatchIndex,
    currentBatch,
    currentItem: currentBatch[0],
    currentIndex: startIndex,
    totalItems,
    totalBatches,
    items,
    batchSize,
  };
}