YouTube's Data API v3 quota is 10,000 units per key per day. For ViralVidVault , which fetches trending videos across seven European regions every seven hours, that quota needs careful management. One careless loop can burn through an entire day's allocation in minutes. The Quota Math Understand what each call costs before writing any fetch logic: API Call Quota Cost search.list 100 units videos.list 1 unit channels.list 1 unit playlistItems.list 1 unit A naive approach — searching each category in each region — means 7 regions times 15 categories times 100 units = 10,500 units per fetch cycle. That's more than one key allows per day. Key Rotation Architecture Multiple API keys, rotated by usage.…