{"slug": "i-built-the-same-app-with-fable-5-opus-4-8-and-sonnet-5-the-results-werent-even", "title": "I Built the Same App with Fable 5, Opus 4.8, and Sonnet 5…The Results Weren’t Even Close", "summary": "Anthropic released three coding models—Fable 5, Opus 4.8, and Sonnet 5—and a developer built the same expense tracker app with each, finding significant performance differences based on prompt counts.", "body_md": "Member-only story\n\n# I Built the Same App with Fable 5, Opus 4.8, and Sonnet 5…The Results Weren’t Even Close\n\nAnthropic now has three models that can code:\n\n- Fable 5 at the top\n- Opus 4.8 in the middle\n- And Sonnet 5 as the new free default.\n\nI built the same app on all three.\n\nI used the same spec, the same stack, and the same judgment criteria. The prompt counts tell the whole story.\n\n## My Spec\n\nI used a real client spec.\n\nAn expense tracker with five features:\n\n- Auth via email/password with protected routes\n- Dashboard with total spending, category breakdown chart, and monthly trend line\n- Add expense form with description, amount, category dropdown, and date picker\n- Expenses table with category filter and CSV export\n- Mobile responsive throughout\n\nThe spec(Remember to add your Supabase project URL and anon key):\n\n```\nBuild a team expense tracker app.Stack: React, Vite, TypeScript, Tailwind CSS, Supabase.Supabase project URL and anon key are in .env as VITE_SUPABASE_URL and VITE_SUPABASE_ANON_KEY.The database…\n```\n\n", "url": "https://wpnews.pro/news/i-built-the-same-app-with-fable-5-opus-4-8-and-sonnet-5-the-results-werent-even", "canonical_source": "https://pub.towardsai.net/i-built-the-same-app-with-fable-5-opus-4-8-and-sonnet-5-the-results-werent-even-close-61d316461e7f?source=rss----98111c9905da---4", "published_at": "2026-07-15 03:01:14+00:00", "updated_at": "2026-07-15 03:23:57.464480+00:00", "lang": "en", "topics": ["artificial-intelligence", "large-language-models", "ai-products", "developer-tools"], "entities": ["Anthropic", "Fable 5", "Opus 4.8", "Sonnet 5"], "alternates": {"html": "https://wpnews.pro/news/i-built-the-same-app-with-fable-5-opus-4-8-and-sonnet-5-the-results-werent-even", "markdown": "https://wpnews.pro/news/i-built-the-same-app-with-fable-5-opus-4-8-and-sonnet-5-the-results-werent-even.md", "text": "https://wpnews.pro/news/i-built-the-same-app-with-fable-5-opus-4-8-and-sonnet-5-the-results-werent-even.txt", "jsonld": "https://wpnews.pro/news/i-built-the-same-app-with-fable-5-opus-4-8-and-sonnet-5-the-results-werent-even.jsonld"}}