SF Ruby Meetup @ Chime, June 4 Recap
SF Ruby Conference CFP, JRuby, Clickhouse, Langchain.rb, Leva, Active Agent, Foobara, Amplified.dev, Pretty Todo, and SF Ruby AI Hackathon!
Here’s the recap of the SF Ruby meetup this week! You’re probably here for the conference updates, but that’s just to entertain you before we open ticket sales on July 3.
Thank you to Chime for hosting, and Gusto for sponsoring travel for 2 speakers, Charles and Kieran.
Announcing the San Francisco Ruby Conference 2025!
CFP open until July 13 at cfp.sfruby.com
Topics: new open source including AI, Ruby and Rails at scale, Ruby startup demos
Early bird tickets ($300) go live on July 3, sign up here for updates
First sponsors: Chime, Bolt.new, Gusto (big shoutout for their commitment to Ruby and Rails)
Ruby & AI Hackathon: July 19 at Sentry, sign up at lu.ma/sfruby
Talks Breakdown
1. Optimize Your Ruby World with JRuby – Charles Oliver Nutter
JRuby 10 now supports Ruby 3.4 and Rails 8
Unlocks JVM superpowers: real parallelism, garbage collection, and Java ecosystem integration
Live demo: Built a GUI charting app with JFreeChart using pure Ruby
2. RubyGems Analytics at Scale – Melvyn Peignon (ClickHouse)
Analyzed 200B+ rows of download logs with zero sampling
4B new rows/month processed via ClickHouse’s S3 integration
Demo: gem data live on sql.clickhouse.com (select rubygems in queries)
Coming soon: real-time dashboards for rubygems
3. Langchain.rb Update: Andrei Bondarev shared his learnings and announced v2.0 with tighter Rails integration
Andrei’s Langchain.rb pioneered AI/LLM tooling for Ruby
Key learning: deeper integration with Rails is needed
Future roadmap includes rebranding and deeper integration into Rails
4. Systematic LLM Evaluation – Kieran Klaassen (Cora)
Introducing Leva – open-source eval framework for Rails
$100k saved by switching from GPT-4 to Google’s Gemma 2B (and understanding cost vs. quality tradeoff)
“Evaluation is TDD for AI – without it, you’re just vibing.”
5. Agents Are Controllers – Justin Bowen (Active Agent)
Live demo: Built a cat image generator and multilingual translator
MVC for AI: Prompt contexts = Models, Agents = Controllers, Action Prompts generate Views
Framework highlight: Automatic cost controls for GPT-4/Claude
Star it: ActiveAgent
💡 Open Mic Lightning Round
Pretty Rails Todo: Celina Lopez’s gem beautifies
rails notes(GitHub)Amplified.dev: Brian Douglas shared his TDD implementation of Conway's Game of Life in Ruby (check out the SF Ruby branch), and he’s looking for feedback.
Foobara, a command-centric framework for complex domains by Miles Georgi. Check it out.
Sarah Mei’s newsletter launch (sarahmei.substack.com)
SF Ruby AI Hackathon: Kamil Nicieja invites everyone to our next event and asks if someone can “code a whole app without keyboard”. Sign up.
🙌 Shoutouts & Next Steps
Huge thanks to Chime for hosting + Gusto for sponsoring travel for two speakers
Join us: SF Ruby Slack | Conference Updates (it’s here!)
Watch the full recording on YouTube