KIkiwicopple·Apr 11, 2025Submission
Show HN: Pg_CRDT – CRDTs in Postgres Using Automerge
11 points · Open discussionsupabase
pg_crdt
C2022–2025
supabase / pg_crdt
pg_crdt
CRDT support in Postgres (experimental)
2Distinct people
4Mentions
0Explicit recommenders
649GitHub stars
What to know before exploring
What it is
CRDT support in Postgres (experimental)
GitHub
Where it is used
No documented product use has been verified yet.
What people are saying
No recommendation phrase was found in the indexed comments.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
No other repository is repeatedly linked in the same discussions.
This week on Hacker News
Nov 8–Nov 15 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/15/2026, 3:38:16 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by month4 dated mentions
Observed mentions: 2022-12-10 12:20:24 UTC to 2025-04-11 16:53:32 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| Dec 2022 | 2022-12-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 1 | 1 | 0 |
| Jan 2023 | 2023-01-01 00:00:00 UTC | 2023-02-01 00:00:00 UTC | 0 | 0 | 0 |
| Feb 2023 | 2023-02-01 00:00:00 UTC | 2023-03-01 00:00:00 UTC | 0 | 0 | 0 |
| Mar 2023 | 2023-03-01 00:00:00 UTC | 2023-04-01 00:00:00 UTC | 0 | 0 | 0 |
| Apr 2023 | 2023-04-01 00:00:00 UTC | 2023-05-01 00:00:00 UTC | 0 | 0 | 0 |
| May 2023 | 2023-05-01 00:00:00 UTC | 2023-06-01 00:00:00 UTC | 1 | 0 | 1 |
| Jun 2023 | 2023-06-01 00:00:00 UTC | 2023-07-01 00:00:00 UTC | 0 | 0 | 0 |
| Jul 2023 | 2023-07-01 00:00:00 UTC | 2023-08-01 00:00:00 UTC | 0 | 0 | 0 |
| Aug 2023 | 2023-08-01 00:00:00 UTC | 2023-09-01 00:00:00 UTC | 0 | 0 | 0 |
| Sep 2023 | 2023-09-01 00:00:00 UTC | 2023-10-01 00:00:00 UTC | 0 | 0 | 0 |
| Oct 2023 | 2023-10-01 00:00:00 UTC | 2023-11-01 00:00:00 UTC | 0 | 0 | 0 |
| Nov 2023 | 2023-11-01 00:00:00 UTC | 2023-12-01 00:00:00 UTC | 0 | 0 | 0 |
| Dec 2023 | 2023-12-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 0 | 0 | 0 |
| Jan 2024 | 2024-01-01 00:00:00 UTC | 2024-02-01 00:00:00 UTC | 0 | 0 | 0 |
| Feb 2024 | 2024-02-01 00:00:00 UTC | 2024-03-01 00:00:00 UTC | 0 | 0 | 0 |
| Mar 2024 | 2024-03-01 00:00:00 UTC | 2024-04-01 00:00:00 UTC | 0 | 0 | 0 |
| Apr 2024 | 2024-04-01 00:00:00 UTC | 2024-05-01 00:00:00 UTC | 0 | 0 | 0 |
| May 2024 | 2024-05-01 00:00:00 UTC | 2024-06-01 00:00:00 UTC | 0 | 0 | 0 |
| Jun 2024 | 2024-06-01 00:00:00 UTC | 2024-07-01 00:00:00 UTC | 0 | 0 | 0 |
| Jul 2024 | 2024-07-01 00:00:00 UTC | 2024-08-01 00:00:00 UTC | 0 | 0 | 0 |
| Aug 2024 | 2024-08-01 00:00:00 UTC | 2024-09-01 00:00:00 UTC | 0 | 0 | 0 |
| Sep 2024 | 2024-09-01 00:00:00 UTC | 2024-10-01 00:00:00 UTC | 0 | 0 | 0 |
| Oct 2024 | 2024-10-01 00:00:00 UTC | 2024-11-01 00:00:00 UTC | 0 | 0 | 0 |
| Nov 2024 | 2024-11-01 00:00:00 UTC | 2024-12-01 00:00:00 UTC | 0 | 0 | 0 |
| Dec 2024 | 2024-12-01 00:00:00 UTC | 2025-01-01 00:00:00 UTC | 0 | 0 | 0 |
| Jan 2025 | 2025-01-01 00:00:00 UTC | 2025-02-01 00:00:00 UTC | 0 | 0 | 0 |
| Feb 2025 | 2025-02-01 00:00:00 UTC | 2025-03-01 00:00:00 UTC | 0 | 0 | 0 |
| Mar 2025 | 2025-03-01 00:00:00 UTC | 2025-04-01 00:00:00 UTC | 0 | 0 | 0 |
| Apr 2025 | 2025-04-01 00:00:00 UTC | 2025-05-01 00:00:00 UTC | 2 | 1 | 1 |
What Hacker News says
2 sourcesA couple of years ago we shared[0] an experimental extension for CRDTs in Postgres. This was a good start, but it had a major limitation: CRDTs can be very chatty and so they quickly fill up the WAL.
We just released a new version which solves this problem: https://github.com/supabase/pg_crdt
The new approach uses UNLOGGED tables for documents and logged tables for changes. This enables us to merge changes efficiently in-memory, then persists just the changes directly to the WAL (previously it was sending the entire CRDT).
The new version also takes advantage an advanced in-memory object persistence feature in Postgres called "expanded datum"[1] and some optimizations to this feature that are coming in Postgres 18[2]. This allows for more complex operations without serializing and deserializing the documents between every operation, which
Read the rest
gets progressively slower as documents grow.
What is a CRDT? A CRDT (Conflict-free Replicated Data Type) is a data structure that syncs across multiple devices or users. They are used in multi-player applications like Figma and Notion. For example: A shared text editor where multiple people type at once, and everyone sees the same final result without manual conflict resolution.
The end goal here is that you will be able to store CRDTs as a data type in your database, and treat Postgres simply as a "peer". A good example would be storing text for a blog post:
create table posts (
id serial primary key,
title text not null
content autodoc not null default '{}'
);
Repo: https://github.com/supabase/pg_crdt
Docs: https://supabase.github.io/pg_crdt/automerge/
----
[0] initial release/discussion: https://news.ycombinator.com/item?id=33931971
[1] expanded datum: https://www.postgresql.org/docs/current/storage-toast.html#S...
[2] PG18 optimizations: https://www.postgresql.org/message-id/3363452.1737483125%40s...