vaxine VS walex

Hi HN, James, Valter, Sam and the team from ElectricSQL here.

We're really excited to be sharing ElectricSQL with you today. It's an open source, local-first sync layer that can be used to build reactive, realtime, offline-capable apps directly on Postgres with two way active-active sync to SQLite (including with WASM in the browser).

Electric comprises a sync layer (built with Elixir) placed in front of your Postgres database and a type safe client that allows you to bidirectionally sync data from your Postgres to local SQLite databases. This sync is CRDT-based, resilient to conflicting edits from multiple nodes at the same time, and works after being offline for extended periods.

Some good links to get started:

- website: https://electric-sql.com

- docs: https://electric-sql.com/docs

- code: https://github.com/electric-sql/electric

- introducing post: https://electric-sql.com/blog/2023/09/20/introducing-electri...

You can also see some demo applications:

- Linear clone: https://linear-lite.electric-sql.com

- Realtime demo: https://electric-sql.com/docs/intro/multi-user

- Conflict-free offline: https://electric-sql.com/docs/intro/offline

The Electric team actually includes two of the inventors of CRDTs, Marc Shapiro and Nuno Preguiça, and a number of their collaborators who've pioneered a lot of tech underpinning local-first software. We are privileged to be building on their research and delighted to be surfacing so much work in a product you can now try out.

The WAL CDC approach: https://github.com/cpursley/walex?tab=readme-ov-file#publica...

CREATE PUBLICATION news_item FOR TABLE news WHERE (topic IS "AAPL");

What do you mean testing with processes?

I won't suggest these are the best written tests, but I test various processes, supervisors, etc like this:

https://github.com/cpursley/walex/blob/master/test/walex/sup...

You don’t send the entire WAL, just what you subscribe to - and you can even filter via SQL: https://github.com/cpursley/walex?tab=readme-ov-file#publica...

What we do is much if the business logic in Postgres. But then there’s all the other stuff like external integrations, etc.

We handled that by having an Even system built on the Postgres WAL that we use like a callback system.

I put together a little library in Elixir (that originally started out as forked Supabase realtime) for this:

https://github.com/cpursley/walex

Recently added the ability to configure WalEx to forward events to webhooks or EventRelay (so you don’t need to know Elixir).

If you're using Elixir, check out https://github.com/cpursley/walex

I've actually been thinking about turning this idea into a product where you can just point it at your postgres database and select the tables you want to listen to (with filters, like you describe). And have that forwarded to a webhook (with possibility of other protocols).

I'd love to hear folks thoughts on that (and if it would be something people would pay for).

Neat, this is the pattern I've been thinking about for a while now. Also glad to see this is Elixir based.

I've been using https://github.com/cpursley/walex (basically a fork of cainophile via a fork for subabase) to listen to Postgres changes in Elixir.

https://github.com/cpursley/walex

Which is based on WAL logs and doesnt have the same limitations.

Great writeup, just added this to the WalEx readme:

https://github.com/cpursley/walex

(WalEx is an Elixir lib for listening to the WAL and perform callback-like actions with the data)

Very cool.

I'm using Elixir to listen to change events via https://github.com/cpursley/walex (which I basically ripped off from Supabase).