Claude AI Free API Key Not Working in Python? Causes, Limits & Fixes (2026)
Table of Contents Introduction: Why Claude AI Free API Key Fails in Python Claude AI Free vs Paid: Whatβs the Difference? Why the Claude Free API Key Doesnβt Work (Error code: 400 Explained) Claude AI Pricing Explained (Subscription vs API Costs) Start Building with Claude AI for Just $5 How to Start Building with Claude