Power Automate vs. Custom Code: The Decision Framework

Power Automate is the right choice when the workflow lives within the M365 ecosystem, the exception rate is low, and volume is moderate. It handles happy-path automation well and complex stateful exception management poorly.

Custom code is the right choice when the integration requires direct API calls to systems without reliable connectors (carrier portals, legacy AMS platforms), when transformation logic is complex, when the solution needs to own its infrastructure, or when licensing cost at scale makes it cheaper. For high-volume workflows, Azure Functions running custom code can be significantly cheaper than Power Automate flows hitting premium connectors.

The most common production architecture is both. Power Automate handles user-facing workflow triggers in Teams and SharePoint. A custom API handles the heavy lifting: multi-system data fetch, normalization, business rule application, and write-back. The interface between the two is a clean API call, so each side can be maintained and scaled independently.

The single most predictive question: will this process still look the same in two years? If the process is stable, Power Automate's faster build time is a genuine advantage. If the process is evolving, the maintainability of custom code pays for itself quickly.