review 9 min read
GPT-4o vs Claude Sonnet 4.5: We Tested Both for 2 Weeks — Here's the Winner (2026)
After two weeks of daily testing with real development tasks, Claude Sonnet 4.5 edges out GPT-4o for most developers. It's faster for code generation, writes cleaner functions, and costs 40% less per million tokens. But GPT-4o wins on complex reasoning and multimodal tasks.
Jordan Blake
