Changing the Wheels While the Car Is Moving

When John, Garrett and Kris bought Fireside, they inherited an eight-year-old Rails app running on Ruby 2.7, Rails 5, Postgres 9.5, and aging infrastructure that could not simply be switched off and rebuilt.

Two years later, almost every piece has been replaced while podcasts, feeds, and downloads kept running.

In the first episode of The Friday Deploy, they break down how they rebuilt Fireside while it was live, including a jump from Postgres 9.5 to 18 with no downtime for listeners. They talk about reverse-engineering undocumented infrastructure, using Flipper to put the application into read-only mode, testing migrations until they became boring, and letting agents carry work all the way to the final approval.

This is not a story about giving an AI agent one prompt and letting it loose on production. It is about breaking dangerous work into small, verifiable steps and knowing where experience and taste still matter.

They also get into:

• Why verification matters more than another round of prompting
• How multiple models can provide independent reviews
• Giving agents safe, read-only access to production context
• Keeping deterministic work out of nondeterministic agents
• Using real customer data to guide product and interface decisions
• Scheduled tasks as the beating heart of an AI-assisted workflow
• Whether the next generation of software needs a traditional interface at all

The goal is not to eliminate risk. It is to gather enough evidence that shipping stops feeling like a leap of faith.

• Fireside
• Flipper
• Flare