The Pulse: RoR creator sparks new “death of coding by hand” debate

The creator of Ruby on Rails, David Heinemeier Hansson, announced that 37signals has stopped writing code by hand, relying instead on AI agents—citing the release of “Opus 4.5” on Nov 24 2025 as the tipping point. The company is now building native mobile apps with AI assistance and migrating backend services from Ruby to Rust because agents can generate sufficiently performant Rust code. Ruby on Rails is retained for web apps because its convention‑over‑configuration design is especially friendly to AI agents. This shift signals engineers to reconsider manual coding in favor of AI‑augmented development pipelines.

⚡ Key Takeaways

• Opus 4.5 was identified as the “Kodak Brownie” of AI coding, marking an inflection point on Nov 24 2025.
• 37signals is moving backend services to Rust, noting that AI agents can write “good enough” Rust for performance reasons.
• Ruby on Rails remains in use for web applications because its convention‑over‑configuration architecture simplifies agent interaction.
• The organization has declared hand‑written code an “exceptional state,” effectively treating AI‑generated code as the default development mode.

Engineers can leverage mature AI agents to automate large portions of code generation, reducing manual effort and enabling rapid product iteration, especially when using frameworks that align with AI‑friendly patterns.

✅ Practical Steps

1. Apply the concepts from this article to your own system design.

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