Walkthrough: How we do month end close with Expensify and NetSuite in under 4 hours.

Hey everyone. Still getting my feet wet with cloud ops, but my team just streamlined our financial close process and I thought I’d share the technical bits. We got our month-end reconciliation between Expensify and NetSuite down from a couple of days to under 4 hours. The key was automating the data sync and validation.

We use a scheduled AWS Lambda function (Python) to pull the approved expense report data from Expensify's API, transform it, and push it to NetSuite via a RESTlet. The most important part was adding validation checks before the sync runs. Here’s a snippet of our core validation logic:

```python
def validate_expense_report(report):
# Check critical fields
required_fields = ['id', 'amount', 'date', 'customer_id']
for field in required_fields:
if field not in report or report[field] is None:
return False, f"Missing required field: {field}"

# Validate amount is positive
if report['amount'] <= 0:
return False, f"Invalid amount for report ID: {report['id']}"

# Check date is within the closing period
report_date = parse_date(report['date'])
if not (period_start <= report_date <= period_end):
return False, f"Report date out of closing period: {report['id']}"

return True, "Valid"
```

We run this in a Step Functions workflow that stops if validation fails, sending an alert to our #finance-ops Slack channel. We also built a simple dashboard in CloudWatch to track sync status. This automation, plus strict policies in Expensify (like required receipts for anything over $25), cut our manual review time way down. Curious if others have done something similar, especially around handling failed transactions or cost tracking for the Lambda jobs themselves 😅