# Multi-Tenant SaaS Cost Attribution: Correctly Attributing Costs of 1000 Customers Through One API Key

> Source: https://sukruyusufkaya.com/en/learn/token-ekonomisi/multi-tenant-saas-cost-attribution-mimarisi
> Updated: 2026-05-14T14:44:12.206Z
> Category: Token Ekonomisi & LLM Cost Optimization
> Module: Module 4: Cost Attribution
**TLDR:** In B2B SaaS you need to report costs separately for 1000 customers while using a single OpenAI API key. This lesson covers tenant_id propagation, metadata injection, and dashboard segmentation patterns.