I’ve spent years writing CSOM code, and I keep seeing the same performance sins in every codebase I review. Including my own older code, which is the humbling part. For a long time, slow CSOM was just annoying. Users waited, someone made coffee, life went on. Then I sat down with a client to …

TL;DR Problem: Loading taxonomy fields via CSOM for SharePoint list items with many terms is painfully slow. Including taxonomy fields in ViewFields makes the initial query extremely expensive. Solution: Batch-load items in chunks, use FieldValuesForEdit to get raw taxonomy data, and parse the …

TL;DR Problem: Client making 90,000 CSOM calls/month, 88% were redundant EnsureUser operations for users already on the site. Solution: Use FieldUserValue.FromUser() optimistically with ExceptionHandlingScope for server-side try-catch logic. Impact: 75-85% reduction in API calls (90,000 → …