The best way to local-first

Replicache is a client-side sync framework for building realtime, collaborative, local-first web apps. It works with most backend stacks.

Benefits

Realtime collaboration

Users see each others’ changes live, as they happen. No refreshes, no locking.

Instant UI

Say goodbye to roundtrips and progress bars. All reads and writes are “optimistic” by default.

Offline support

Applications can go offline for hours or days and sync up smoothly when they come back online.

BYOB(ackend)

Replicache is client-side technology and works with most backend stacks.

It just works

Conflicts, tabs, schema migrations – Replicache handles the hard parts. You’ll find it’s even more productive than traditional web frameworks.

How it works

Replicache downloading data and caching it.

On a user's first visit, Replicache downloads an initial chunk of data and stores it persistently in the browser.

UI responding instantly while updating server in background.

The application reads and writes only to its local copy of the data. Thus the application responds instantly to all interaction by default.

Replicache syncronizing changes from multiple clients.

As the user moves through the app, additional data is downloaded as necessary. Replicache synchronizes changes to the server and other clients continuously in the background. Users see each others’ changes live.

Replicache merging conflicts from multiple clients.

Conflicts happen if two users edit data concurrently. Replicache merges conflicts using a form of server reconciliation — an intuitive and powerful technique from multiplayer games.

Replicache resolving conflict after client offline.

If sync can’t happen because the server is down or there’s no network, changes are queued persistently until the server comes back. Replicache apps can smoothly transit online, offline, and unreliable networks.

Who’s using Replicache?

vercel.com

“Realtime sync finally made easy and simple.”

“I love the programming model. The pairing with React is perfect.”

Guillermo Rauch

CEO

Malte Ubl

Chief Architect

swiggy.com

“Replicache has solved an important and complex problem for us. It is extremely reliable and performant. Love the product and would recommend it to anyone who needs offline support.”

Siddardha Garimella

Engineering Manager

placemark.io

“Realtime collaboration is too big for early teams to build. For my small team at Placemark, using Replicache meant that collaboration could just work and I can focus on building the product.”