Side Project Spotlight

Mike Zornek wants your software to keep working even when the company behind it disappears. He joins The Trio to explain local-first software, Automerge, and CRDTs, then shares what he learned building LocalCents, an expense tracker that syncs offline edits. Steve digs into collaboration, Kotaro asks about changing data structures, and Mike explains why giving users more control is worth the extra work.

## Chapters

00:00 Introductions & Welcome Mike Zornek

04:22 From Mac Apps to Elixir

12:30 What Is Local-first Software?

22:32 Inside Automerge and CRDTs

36:29 Collaboration Between Equal Peers

42:49 Building LocalCents

48:33 Collisions and Schema Evolution

01:01:57 Fighting for the Users

01:04:37 Keyhive and Access Control

01:07:33 A Little Doom and Gloom

01:10:23 Outro & One More Thing...

01:11:33 Tag

## Show Notes

- Mike Zornek returns to PhillyCocoa and jokingly takes full credit for the iOS gold rush.

- App Store distribution rules helped push Mike from Apple development back to the web and Elixir.

- Mike explains why local-first means more than offline support: collaboration, longevity, privacy, and user ownership matter too.

- Automerge handles persistence and merging independently of the UI, with APIs for different language ecosystems.

- Steve and Mike unpack how a cloud relay can help equal peers exchange changes without becoming the authoritative copy.

- Mike's LocalCents proof of concept syncs expenses between a Mac app and a browser, including edits made offline.

- Collision UI and schema evolution leave plenty of work for application developers even when merging is automatic.

- Mike argues that harder technical problems are worth tackling to give users more power.

- Keyhive's access-control diagrams get scary enough that Mike recommends brewing a pot of coffee first.

- After a little internet doom and gloom, Kotaro shares that BarCamp Philly is back, and Mike plans to attend.

## Links

**Mike Zornek**

Website: https://mikezornek.com

LocalCents: https://mikezornek.com/posts/2026/8/local-cents

**Local-first Software**

Previously on SPS (#117): https://podcast.phillycocoa.org/episodes/117-assumption-one-youre-a-hoarder

Mike's local-first post: https://mikezornek.com/posts/2025/2/what-is-local-first-software/

Ink & Switch paper: https://www.inkandswitch.com/essay/local-first

**Tools and Further Reading**

Automerge: https://automerge.org

Martin Kleppmann: https://martin.kleppmann.com/

Conflict-free replicated data type (CRDT): https://en.wikipedia.org/wiki/Conflict-free_replicated_data_type

Keyhive: https://www.inkandswitch.com/keyhive/notebook/

**One More Thing**

BarCamp Philly: https://barcampphilly.org/

**PhillyCocoa:** https://phillycocoa.org

Intro music: "When I Hit the Floor", © 2021 Lorne Behrman. Used with permission of the artist.