Summary of "Rails World 2025 Opening Keynote - David Heinemeier Hansson"

Summary of Rails World 2025 Opening Keynote by David Heinemeier Hansson

Key Themes & Technological Concepts

Paradox of Modern Software Development
- Despite advances in hardware, open source, and tooling, software development feels slower and more complicated than in the late 1990s.
- Deployment times have regressed from 5 seconds (FTP in 1999) to hours or days in 2025, despite larger teams and more advanced infrastructure.
- The industry suffers from "merchants of complexity" selling complicated tools that add overhead without solving real problems.
Embracing Simplicity and End-to-End Problem Solving
- Developers should accept the core nature of their work as "crud monkeying" (creating, reading, updating, deleting records) and embrace simplicity rather than overcomplicate with unnecessary computer science abstractions.
- Rails has always been a "mega framework" aiming to solve the whole web development problem end-to-end, rather than minimalist frameworks that only address parts of the stack.
- Rails philosophy likened to the Roman Empire at its height ("Paxraelsana") — a comprehensive, well-integrated ecosystem with freedom, ownership, and duty.
New Features and Improvements in Rails 8.1 and Related Tools
- Markdown Support: Rails 8.1 will have native support for Markdown rendering, making it easier to produce Markdown output and integrate with AI tools that prefer Markdown.
- Lexy Text Editor: Replacement for Trix in Action Text, built on Meta’s Lexical framework (used by Facebook, WhatsApp, Instagram). Features live syntax highlighting, Markdown pasting and exporting.
- Action Job Continuations: New job architecture allowing jobs to be paused and resumed, critical for long-running tasks and graceful shutdowns in deployment environments.
- Turbo Offline: Offline caching at the Turbo layer to support offline use cases for both native and web apps, shipping soon in two phases (cache-as-you-go and preemptive caching).
- Action Push (Push Notifications):
  - Native push notifications support for Apple and Google devices, replacing reliance on AWS Pinpoint.
  - Web Push support in Campfire (a native web app) is functional but needs extraction and simplification; community help requested.
- Development Environment Simplifications:
  - Dropping Puma-dev in favor of using localhost with explicit ports for running multiple Rails apps locally.
  - Hybrid approach to Docker: Use native Ruby installs (managed by mies) for Ruby versions and Docker only for databases/services.
- Testing Philosophy Changes:
  - System tests are mostly deprecated due to instability and slowness; only minimal smoke tests recommended.
  - Emphasis on running tests locally, leveraging faster modern CPUs (Apple M-series, Framework laptops) instead of slow cloud runners.
  - New DSL in Rails 8.1 for local CI runs and GitHub integration requiring human sign-off after local tests pass, relying on trust and developer responsibility.
Omachi: A Custom Linux-Based Developer OS
- David has created "Omachi," a Linux-based OS optimized for Ruby on Rails development.
- Installation demo showed setup in under 5 minutes on a new Framework laptop.
- Omachi includes preconfigured tools: Git (with LazyGit TUI), Ruby version manager (mies), Docker, databases, and a terminal-centric UI (NeoVim, Starship prompt).
- Focus on developer joy, speed, and freedom from vendor lock-in (especially Apple).
- USB keys with Omachi available at the conference for serious installers.
Reimagining Infrastructure: Micro Data Centers and Edge Computing
- Large data centers are expensive and introduce latency; mini data centers (micro data centers) in many locations could drastically reduce latency and improve performance.
- Network latency (speed of light limits) is a fundamental bottleneck, e.g., New York to Sydney RTT ~220ms, which adds up over multiple requests.
- Goal: Target response times under 200ms (comparable to a Formula One driver’s reaction time).
- Active Record Tenancy: One database per customer to enable distributing data closer to users.
- Beamer: A new project for replicating SQL-like databases at scale, designed for tens of thousands of databases and transactions.
- Kamal GeoProxy: Geo-aware routing to direct users to the nearest data center/outpost, with session affinity to avoid stale reads.
- This distributed architecture aims to combine performance, privacy, and scalability.
Philosophy of Open Source and Developer Freedom
- Open source allows full ownership and freedom to change any part of the stack.
- Encouragement to reject vendor lock-in and embrace end