Show HN: Omni – Open-source workplace search and chat, built on Postgres

Doublon · 2026-03-02T09:36:59 1772444219

Interesting!

I also started to build something similar for us, as an PoC/alternative to Glean. I'm curious how you handle data isolation, where each user has access to just the messages in their own Slack channels, or Jira tickets from only workspaces they have access to? Managing user mapping was also super painful in AWS Q for Business.

prvnsmpth · 2026-03-02T09:51:27 1772445087

Thank you!

Currently permissions are handled in the app layer - it's simply a WHERE clause filter that restricts access to only those records that the user has read permissions for in the source. But I plan to upgrade this to use RLS in Postgres eventually.

For Slack specifically, right now the connector only indexes public channels. For private channels, I'm still working on full permission inheritance - capturing all channel members, and giving them read permissions to messages indexed from that channel. It's a bit challenging because channel members can change over time, and you'll have to keep permissions updated in real-time.

swaminarayan · 2026-03-02T09:52:15 1772445135

How well does the Postgres-only approach hold up as data grows — did you benchmark it against Elasticsearch or a dedicated vector DB?

prvnsmpth · 2026-03-02T10:05:26 1772445926

I've done small scale experiments with up to 100-500k rows, and did not notice any significant degradation in search query latency - p95 still well under 1s.

I haven't directly compared against Elasticsearch yet, but I plan to do that next and publish some numbers. There's a benchmark harness setup already: https://github.com/getomnico/omni/tree/master/benchmarks, but there's a couple issues with it right now that I need to address first before I do a large scale run (the ParadeDB index settings need some tuning).

cultofmetatron · 2026-03-02T11:19:59 1772450399

we have a pretty intensively used postgres backed app handling thousands of users concurrently. After 6 years and thousands of paying custoners, we are only now approaching to the limits of what it can support on the horizon. TLDR: when you get there, you can hire some people to help you break things off as needed. if you're still trying to prove your business model and carve yoruself a segment of the market, just use postgres

prvnsmpth · 2026-03-02T11:27:27 1772450847

Thanks for sharing! Big part of the reason why I decided on postgres, everything I've read about people using it in prod tells me that most organizations never really grow beyond requiring anything more than what it offers.

hobs · 2026-03-02T11:50:56 1772452256

Most of the time just re-casting what you want in a horizontally shardable way is the "right" way to do it with any rdbms (if you scale) but at this point you can get boxes on AWS with 32TiB of ram, and most organizations don't have that much total data across their entire suite of stuff (many do, most don't.)

keyle · 2026-03-02T10:12:45 1772446365

I've done some RAG using postgres and the vector db extension, look into it if you're doing that type of search; it's certainly simpler than bolting another solution for it.

prvnsmpth · 2026-03-02T10:19:29 1772446769

Yeah, Omni uses Postgres and pgvector for search. ParadeDB is essentially just Postgres with the pgsearch extension that brings in Tantivy, a full-text search engine (like Apache Lucene).

vladdoster · 2026-03-02T10:04:46 1772445886

Multiple pages link to a `API Reference` that returns a 404

prvnsmpth · 2026-03-02T10:11:02 1772446262

Oops, sorry! That page is still a WIP, haven't pushed it yet. The plan was to expose the main search and chat APIs so that users can build integrations with third-party messaging apps (e.g. Slack), but haven't gotten around to properly documenting all the APIs yet.