Jazz - the DB that syncs

Huge thanks to our speakers, volunteers, venue staff, and sponsors @cloudflare.social, @powersync.com, @coderabbitai.bsky.social, @jazz.tools, @bsky.app, @tangled.org, and solstone.app for making this possible at an accessible price. And to everyone who came: this only works because you show up.

Wrapped up @localfirstconf.com in a summery Berlin beer garden yesterday. Always a special crowd to me because it’s where @jazz.tools got born 2 years ago. And where else can you hang out with Martin Kleppmann, Dan Ingalls and people who only use Mistral models at the same place?

history of distributed systems with the 🐐 at @localfirstconf.com

TLDR

For his master's thesis, @siidorow.dev interviewed me about how @jazz.tools fits into the landscape of sync engines and local-first DBs. Now that it's published (congrats!) I can say that it is *the* most rigorous & precisely categorized overview of our field! PDF: aaltodoc.aalto.fi/server/api/c...

Building @jazz.tools v2 in public, Ep 3 Main learning: ground your LLMs in your concrete problem, build jigs, religiously optimize code iteration speed. The last couple days were more perf work, driven by a specific target that a commercial use case gave us.

Fluid migrations are one of the most novel features of @jazz.tools v2. Inspired by @inkandswitch.com’s Cambria paper, they re-imagine migrations: - not a stop-the-world global mutation - but bidirectional lenses (mappings) - translating between a pair of schema versions - that can be chained

As promised, yapping more on @jazz.tools After launching the v2 alpha at React Miami our focus has been polish and perf, and there is a lot to do. Often, refactoring and nailing down semantics go hand in hand with performance.

My talk from @sync_conf 2025 is ready! Check it out to learn how: 1) CRDTs + cryptographic permissions work 2) @jazz.tools is now a general-purpose database 3) our unique Jazz Cloud infra compares to - traditional stacks - other sync engines - Durable Objects www.youtube.com/watch?v=wils...

@anselm.io (@jazz.tools)will help us grapple with the question of when our sync systems become a full-fledged database. Anselm's talks at Local-First Conf have always been crowd-pleasers, so he's sure to delight at Sync Conf.

Shipping the feature and going to bed early

it has begun

People keep asking us if @jazz.tools will have vector search... What's better than building a first class vector search feature for Jazz in maybe a couple months? A single person right now being able to ship it as a small, very neat, very high quality library *on top of* Jazz! vimeo.com/1111603758

Given our realisation that *actually, @jazz_tools is a database* (see QT)... ...we're hosting another meetup in SF this Wednesday! (RSVP below!) Thinking of Jazz as a DB begs the question: how does it fit into the stack? bsky.app/profile/jaz...

The wait is finally over! It’s time for another FUTURE OF CODING LONDON Tuesday, July 22 @ 18:00 Kindly hosted by Granola at their office Sponsored by @jazz.tools RSVP here: lu.ma/lo2medup Demo/Talk submission here: foc-london.notion.site/21c379f0e4c...

Two weeks after alpha-3 which foreshadowed our move to @jazz.tools for greater stability, alpha-4 gets it done! blog.muni.town/roomy-space-... Special shoutout to @flo-bit.dev who took the lead on this release. Up next is bridging so Roomy & Discord (later Matrix) folk can share the same space.

My full talk from @localfirstconf.com is up! Featuring 1y of progress on @jazz.tools And: two big announcements + the most sketchy, yet successful demo I've ever done. - Waffle, a Discord/Slack alternative built on Jazz - Soul, our upcoming AI toolkit for Jazz www.youtube.com/watch?v=e3-y...

> The AI just is "one more collaborator" and you just dump the tokens into Jazz state as they come in. This is the correct mental model

Streamed LLM responses are the perfect example of why we didn't base @jazz.tools on an existing DB, but are building a new backend + DB from scratch. Originally we just wanted to support Figma/Notion-like apps where we knew we had to sync 100,000s of tiny edits per second... 🧵 x.com/marbemac/st...

Sync engines are an incremental improvement to the "centralised server + client" model - the minimal possible step towards the real-time nature of apps today. But we can do much better 🧵

Love meeting new builders online me: “Hey Jazz supports ProseMirror now, we should build a ProseKit example or something” *minds my own business for 3h* @ocavue.bsky.social: “here’s the example”

"Local First is accidentally perfect for the AI age" Great talk from @anselm.io of @jazz.tools on how AI and Local First software are the perfect partners.

@localfirstconf.com is off to a fantastic start, the number of new people is mind blowing. For us at @jazz.tools, today was all about getting hands-on and helping people building cool stuff with Jazz - and handing out our first vibe coding certifications!

my endless shared canvas with @jazz.tools is kinda usable now, come draw something at: flo-bit.dev/jazz-endless...

Megathread of everything we're announcing for @jazz.tools at @localfirstconf.com It's been a hell of a year in the best sense and I can't wait to share what we've been cooking. (And this doesn't even include our "one more thing" 🤫) Stay tuned as I expand on details over the next couple days!

Join the @jazz.tools team at Local-First Conf! - learn how to vibe-code apps with Jazz - get a first glimpse of AI that “already knows how to use your app”

I love doing adopter support calls for @jazz.tools "No you don't need to do that..." "This extra indirection isn't necessary..." "Yes, you can use CoValues as both UI state and the persisted source of truth - you don't need to copy back and forth" "No you don't need to 'save' "

Discord driven development Shoutout to @jmsv.bsky.social for the 3h suggestion-to-🚢 Shoutout to @bensleveritt@mastodon.social for the months of gruelling work in the ProseMirror mines that made this a quick win

Nothing better than telling people to edit just their package.json for a 12x perf improvement. I still think we can do better for this particular hot path internally. But their app’s “screen of everything” *cold start* is now bottlenecked by React & the DOM! bsky.app/profile/jaz...

Security is the most subtle challenge in full-stack apps. Many devs still re-invent the wheel, building access control with low-level tools like RLS (or worse, ad-hoc backend code) 😱 The security design of @jazz.tools is a godsend for vibe coders (and experienced devs!) 🧵

Very happy with how this comparison page turned out and proud to have co-sponsored it as @jazz.tools! The fact that such a thorough, fair comparison page could be created by competing vendors and open-source projects is a testament to the spirit of collaboration in the local-first community.

users in Portugal and Spain are asking us if we can make Jazz even more batteries included 🫂

coming soon

Just finished working through the [React tutorial](jazz.tools/docs/react/g...) at @jazz.tools and it _is_ pretty impressive how easy it is.

Last year @localfirstconf.com, I showed @jazz.tools to a wider audience for the first time - a humble MVP built in my spare time I found investors, team members and our first prod user there ❤️ This year, there'll be 13 of us and so much progress to share! Stay tuned 🎵

This is a pre-announcement! We'll do another @jazz.tools meetup in SF on Apr 1, but this time it'll be a vibe coding mini-hackathon! Prizes and more details TBA soon! lu.ma/1fru6ldd