A JavaScript framework to build offline-first but collaborative webapp

📰 Hacker News · jjzhiyuan

Learn how to build offline-first but collaborative web apps with Replicache, a JavaScript framework that enables real-time sync and zero-latency user interfaces

intermediate Published 20 Oct 2022

Action Steps

Explore the Replicache documentation to learn how to integrate it into your web app
Use the Replicache client-side sync framework to build a realtime collaborative web app
Configure Replicache to work with your existing backend stack
Test and deploy your Replicache-powered web app to ensure seamless offline-to-online transitions
Migrate to Zero, the new plan to bring sync to the entire web, as recommended by the Replicache team

Who Needs to Know This

Frontend developers and full-stack developers can benefit from using Replicache to build collaborative web apps with offline support and real-time sync. This framework is particularly useful for teams working on web applications that require instant UI updates and seamless offline-to-online transitions.

Key Insight

💡 Replicache enables real-time sync and zero-latency user interfaces for web apps, making it ideal for collaborative applications that require instant updates and offline support

Key Takeaways

Learn how to build offline-first but collaborative web apps with Replicache, a JavaScript framework that enables real-time sync and zero-latency user interfaces

Full Article

Title: Replicache

URL Source: https://replicache.dev/

Published Time: Thu, 02 Jul 2026 04:21:43 GMT

Markdown Content:
[![Image 1: Replicache logo](https://replicache.dev/replicache.svg)](https://replicache.dev/#)
* [![Image 2: Replicache logo](https://replicache.dev/replicache.svg)](https://replicache.dev/#)

* [Why](https://replicache.dev/#)
* [Status](https://replicache.dev/#)
* [How](https://replicache.dev/#)
* [Reactions](https://replicache.dev/#)
* [Contact](https://replicache.dev/#)
* [Blog](https://rocicorp.dev/blog)
* [Docs](https://doc.replicache.dev/)
* [Get started](https://replicache.dev/#)

* [Why](https://replicache.dev/#)
* [Status](https://replicache.dev/#)
* [How](https://replicache.dev/#)
* [Reactions](https://replicache.dev/#)
* [Contact](https://replicache.dev/#)
* [Blog](https://rocicorp.dev/blog)
* [Docs](https://doc.replicache.dev/)
* [Get started](https://replicache.dev/#)

# Realtime sync for any backend stack

Replicache is a client-side sync framework for building realtime, collaborative web apps with zero-latency user interfaces. It works with most backend stacks.

[Video 1](https://www.youtube.com/watch?v=GTid9iwWX0Y)

## Status

After five years, thousands of developers, and millions of end users, Replicache is now in maintenance mode. We have[open-sourced the code](https://github.com/rocicorp/mono/tree/main/packages/replicache)and no longer charge for its use.

We have shifted focus to [Zero](https://zero.rocicorp.dev/) – our plan to bring sync to the entire web.

We will continue to support Replicache, but won't add new features. Existing users should migrate to Zero as they are able.

## Benefits

![Image 3](https://replicache.dev/benefits/realtimeCollab.svg)

### Realtime collaboration

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

![Image 4](https://replicache.dev/benefits/instantUI.svg)

### Instant UI

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

![Image 5](https://replicache.dev/benefits/offline.svg)

### Offline support

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

![Image 6](https://replicache.dev/benefits/byob.svg)

### BYOB(ackend)

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

![Image 7](https://replicache.dev/benefits/itworks-white.svg)

### 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

![Image 8: Replicache downloading data and caching it.](https://replicache.dev/how-01.svg)
On a user's first visit, Replicache downloads an initial chunk of data and **stores it persistently in the browser**.

![Image 9: UI responding instantly while updating server in background.](https://replicache.dev/how-02.svg)
The application reads and writes only to**its local copy** of the data. Thus the application responds **instantly** to all interaction by default.

![Image 10: Replicache syncronizing changes from multiple clients.](https://replicache.dev/how-03.svg)
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**.

![Image 11: Replicache merging conflicts from multiple clients.](https://replicache.dev/how-04.svg)
Conflicts happen if two users edit data concurrently. Replicache merges conflicts using a form of[server reconciliation](https://en.wikipedia.org/wiki/Client-side_prediction)— an intuitive and powerful technique from multiplayer games.

![Image 12: Replicache resolving conflict after client offline.](https://replicache.dev/how-05.svg)
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 onlin

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A JavaScript framework to build offline-first but collaborative webapp

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