By month 14 of our Auth0 9.0 contract, we were burning $42k/month on authentication for 500k monthly active users (MAUs) — with p99 login latency hitting 2.1s during peak traffic, and 3 critical outages traced to Auth0 rate limits in Q3 2023. Migrating to NextAuth 5.0 cut our auth costs by 62% (to $16k/month), dropped p99 login latency to 87ms, and eliminated third-party auth outages entirely. Here’s how we did it, with full code, benchmarks, and zero downtime. 📡 Hacker News Top Stories Right Now Ghostty is leaving GitHub (1557 points) ChatGPT serves ads. Here's the full attribution loop (86 points) Before GitHub (238 points) Claude system prompt bug wastes user money and bricks managed agents (33 points) Carrot Disclosure: Forgejo (87 points) Key Insights NextAuth 5.0’s edge-compatible session middleware reduced auth infrastructure costs by 62% for 500k MAUs compared to Auth0 9.0’s managed tier.…