Launch HN: Onyx (YC W24) – Open-source chat UI

252 points by Weves 8 days ago


Hey HN, Chris and Yuhong here from Onyx (https://github.com/onyx-dot-app/onyx). We’re building an open-source chat that works with any LLM (proprietary + open weight) and gives these LLMs the tools they need to be useful (RAG, web search, MCP, deep research, memory, etc.).

Demo: https://youtu.be/2g4BxTZ9ztg

Two years ago, Yuhong and I had the same recurring problem. We were on growing teams and it was ridiculously difficult to find the right information across our docs, Slack, meeting notes, etc. Existing solutions required sending out our company's data, lacked customization, and frankly didn't work well. So, we started Danswer, an open-source enterprise search project built to be self-hosted and easily customized.

As the project grew, we started seeing an interesting trend—even though we were explicitly a search app, people wanted to use Danswer just to chat with LLMs. We’d hear, “the connectors, indexing, and search are great, but I’m going to start by connecting GPT-4o, Claude Sonnet 4, and Qwen to provide my team with a secure way to use them”.

Many users would add RAG, agents, and custom tools later, but much of the usage stayed ‘basic chat’. We thought: “why would people co-opt an enterprise search when other AI chat solutions exist?”

As we continued talking to users, we realized two key points:

(1) just giving a company secure access to an LLM with a great UI and simple tools is a huge part of the value add of AI

(2) providing this well is much harder than you might think and the bar is incredibly high

Consumer products like ChatGPT and Claude already provide a great experience—and chat with AI for work is something (ideally) everyone at the company uses 10+ times per day. People expect the same snappy, simple, and intuitive UX with a full feature set. Getting hundreds of small details right to take the experience from “this works” to “this feels magical” is not easy, and nothing else in the space has managed to do it.

So ~3 months ago we pivoted to Onyx, the open-source chat UI with:

- (truly) world class chat UX. Usable both by a fresh college grad who grew up with AI and an industry veteran who’s using AI tools for the first time.

- Support for all the common add-ons: RAG, connectors, web search, custom tools, MCP, assistants, deep research.

- RBAC, SSO, permission syncing, easy on-prem hosting to make it work for larger enterprises.

Through building features like deep research and code interpreter that work across model providers, we've learned a ton of non-obvious things about engineering LLMs that have been key to making Onyx work. I'd like to share two that were particularly interesting (happy to discuss more in the comments).

First, context management is one of the most difficult and important things to get right. We’ve found that LLMs really struggle to remember both system prompts and previous user messages in long conversations. Even simple instructions like “ignore sources of type X” in the system prompt are very often ignored. This is exacerbated by multiple tool calls, which can often feed in huge amounts of context. We solved this problem with a “Reminder” prompt—a short 1-3 sentence blurb injected at the end of the user message that describes the non-negotiables that the LLM must abide by. Empirically, LLMs attend most to the very end of the context window, so this placement gives the highest likelihood of adherence.

Second, we’ve needed to build an understanding of the “natural tendencies” of certain models when using tools, and build around them. For example, the GPT family of models are fine-tuned to use a python code interpreter that operates in a Jupyter notebook. Even if told explicitly, it refuses to add `print()` around the last line, since, in Jupyter, this last line is automatically written to stdout. Other models don’t have this strong preference, so we’ve had to design our model-agnostic code interpreter to also automatically `print()` the last bare line.

So far, we’ve had a Fortune 100 team fork Onyx and provide 10k+ employees access to every model within a single interface, and create thousands of use-case specific Assistants for every department, each using the best model for the job. We’ve seen teams operating in sensitive industries completely airgap Onyx w/ locally hosted LLMs to provide a copilot that wouldn’t have been possible otherwise.

If you’d like to try Onyx out, follow https://docs.onyx.app/deployment/getting_started/quickstart to get set up locally w/ Docker in <15 minutes. For our Cloud: https://www.onyx.app/. If there’s anything you'd like to see to make it a no-brainer to replace your ChatGPT Enterprise/Claude Enterprise subscription, we’d love to hear it!

tomasphan - 8 days ago

This is great, the value is there. I work for a F100 company that is trying (and failing) to build this in house because every product manager fundamentally misunderstands that users just want a chat window for AI, not to make their own complicated agents. Your biggest competition in the enterprise space, Copilot, has terrible UI and we only put up with it because it has access to email, SharePoint and Teams.

rao-v - 8 days ago

I was pretty excited for Onyx as a way to stand up a useful open source RAG + LLM at small scale but as of two weeks ago it was clearly full of features ticked off a list that nobody has actually tried to use. For example, you can scrape sites and upload docs but you can’t really keep track of what’s been processed within the UI or map back to the documents cleanly.

It’s nice to see an attempt at an end to end stack (for all that it seems this is “obvious” … there are not that many functional options) but wow we’ve forgotten the basis of making useful products. I’m hoping it gets enough time to bake.

CuriouslyC - 7 days ago

Something like this has a very limited shelf life as a product. What users need from chat is very user specific, trying to be the one chat to rule them all is not gonna end well, and as models get more capable each chat experience is going to need to be more customized.

Something like this could have a nice future as an open source chat framework for building custom UIs if it's well made and modular, but that isn't gonna work well with a SaaS model.

unleashit - 6 days ago

Side question: It looks interesting but what's with the trend of open source projects providing such bloated installs? The recommended getting started with docker (which first recommends cloning a 350mb repo) seems to assume you need to scale to 100s+ users. At a glance, in their default docker compose I counted no less than 12 containers including nginx, redis and minio. I can't imagine any of these are necessary to run an app on a single localhost machine.

I understand they're trying to attract enterprisy customers, but even some of those are probably going to want to try it out first. Would be nice to have an easy minimal install option that doesn't require a deep dive into the project to figure out.

crocowhile - 7 days ago

In a landscape where every week we have a different leading model, these systems are really useful for the power users because they keep the interface and models constant and allow to switch easily using API via openrouter or naga. I have been using openwebui which is under active development but I'll give this a try.

jmward01 - 6 days ago

We need more diversity in this space. The fundamental UI experience, and environment hooks, aren't set in stone so we need many players, open and closed, to more fully explore this space.

gunalx - 7 days ago

Does it support multimodal documents?

My main gripe with openwebui, in addition to it being slow is the fact that it mangles documents in the OCR step. tables that could have been understood great by an multi modal llm, just gets mangled by the ocr and lost instead of storing both a text and original representation.

Being able to properly searcbin the knowlege base lime the llm does, but manually would be nice (like get recommendations for docs to add).

My usecase is mostly writing, so having a integrated document refinery editor is also a nice feature list.

I'm probably rambling but these are my base use-cases for a llm ui I personally have found.

Tsarp - 7 days ago

If we are already comfortable with our enterprise chatgpt subscription, how might this be of value. Given that it does RAG, tool calling, has all the SSO stuff/collab? Or are we not the target customer.

Just curious. Especially with both OpenAI and Anthropic really also outpacing startups in release cadence unlike previous cycles.

Guessing your selling point is any model no locking (Assuming we are happy with the privacy SOC 2 etc guarantees on enterprise contracts here)

jryio - 7 days ago

Do you know what's completely missing from all of these products like anything LLM and Onyx...

a mobile application that has parity on the same features that ChatGPT and Claude does...

jiehong - 7 days ago

The title could contain "LLM-chat UI", because "chat ui" also means like an instant messaging UI.

I'm nitpicking, congrats on the launch!

panki27 - 7 days ago

What does this do that OpenWebUI (or one of the many of other solutions) does not?

solarkraft - 7 days ago

One thing I really care about is extensibility. Every now and then one of the big consumer apps adds a feature I really like and the self-hosted solution should have some way to integrate that.

The main thing I really care about is voice mode, as that's my far preferred way of interacting with LLMs for longer backs and forths (most apps I've seen disable a lot of other functionality during it, which I hate, btw).

Two other things I would like to see are canvas mode and scheduled actions (with decision making capability - e.g. "send a notification if X happens").

I assume such features are going to continue being invented, so I find extensibility to be a huge deal. So much so that one thing I could imagine going really well would be a UI on top of Langchain, which already has most of the facilities for that!

zaptheimpaler - 6 days ago

I would love to set this up, I really want all my chats to be on one platform. The problem is, the AI companies seem to want the opposite.

My main concern is how well do all the extra features work compared to the native versions? Like web search, RAG on a document, or deep research, adding images, voice chats - my understanding is the models providers don't provide any API's for any of this stuff, so you have your own implementations of all the extra stuff right? Usually I find the open source versions of all these features aren't up to par with the corporate versions and they lag behind in development.

dannylmathews - 7 days ago

The license on this project is pretty confusing. The license at the root of the project links to backend/cc/LICENSE.md which says you need a subscription license to use the code.

Can you call it open source if you need a subscription license to run / edit the code?

echelon - 7 days ago

> open-source

How do you plan to make money? I'm very serious about this question.

I'm in an adjacent (but highly non-LLM field) and I'm grappling with this myself.

Selling compute or being a middle man and paying for API use seems like a low-margin game. It'd have to be with giving convenient search access to org data or something along those lines? Perhaps expanding into some kind of agent product?

My creativity on making money with LLMs is pretty sparse as I'm in the graphics world. But I'm certainly interested in "making money on aggregation" ideas.

Also, are you worried about competitors forking your code?

asdev - 7 days ago

Aren't most of the large frontier model providers SOC 2 compliant? I think AWS Bedrock is also SOC 2 compliant. Not sure why you would need to self host anything then as you'll get turnkey secure solutions from the bigger plays

nibab - 6 days ago

fabulous work. ive been following you since danswer. you certainly create a lot of value and have been successful in getting the community to cover the long tail of integrations.

its interesting to see how "lock-in" is the main pitch here. all things considered, i don't think "lock-in" is relevant at all unless the activity performed with the tool is highly strategic to the company.

you could argue that some orgs may not want openai/anthropic to have their sensitive data leave the parameter, but im also here to tell you that even the most privacy sensitive companies in the world probably resolve this by having a proxy in between the users and the LLM APIs from the labs.

so where does this leave you ? cost savings from OSS? maybe, but its hard to imagine that we are in the phase of the adoption cycle where companies have become as acutely aware of costs as you think they are.

my 2c - focus on the integrations and see which one gets most traction. that will be your value capture mechanism long-term.

oliya88 - 7 days ago

Impressive work on Onyx! It’s rare to see an open-source AI platform nail both enterprise-grade security (RBAC, SSO, 40+ connectors) and a truly polished UX. The attention to model-specific quirks—like GPT’s Jupyter assumptions—shows deep practical experience. Already spinning it up locally; thanks for keeping it open and extensible

oliya88 - 7 days ago

It’s rare to see an open-source AI platform nail both enterprise-grade security (RBAC, SSO, 40+ connectors) and a truly polished UX. The attention to model-specific quirks—like GPT’s Jupyter assumptions—shows deep practical experience. Already spinning it up locally; thanks for keeping it open and extensible

visarga - 7 days ago

That sidebar of past chats is where they go to be lost forever. Nobody came up with a UI that has decent search experience. It's like reddit internal search engine, but a bit worse.

terminalkeys - 7 days ago

The UI looks so close to Open WebUI I was shocked this isn't a fork. It even looks like it takes OWUI's unique model customization features, but makes it agents.

Might have to try this out. OWUI's lagging docs has made managing my own self hosted instance a pain.

PS: Your _See All Connectors_ button on the homepage is 404ing.

bilekas - 7 days ago

Interesting product and best of luck with it.

> but I’m going to start by connecting GPT-4o, Claude Sonnet 4, and Qwen to provide my team with a secure way to use them

I did get a little giggle out of that because I've never heard anyone say that hooking up 3rd party llms to anything was any way secure.

adam2221 - 4 days ago

I saw that in the new versions (2.x), you kind of broke the use of on-prem deployed LLMs, which is the whole point of Onyx.

mediumsmart - 6 days ago

I have been using onyx for years and quite happy with it.

https://titanium-software.fr/en/onyx.html

johnxie - 7 days ago

Kudos on the launch! Most of the real work isn’t the chat box. It’s keeping context stable, memory reliable, and tool calls from drifting when things get complex. That’s where projects usually break, and also where the interesting problems are now. :)

alalani1 - 7 days ago

Do you let organizations white-label it so its more customized (i.e. remove the Onyx branding, preload it with their internal MCP servers / docs) and feels like their own internal chat tool?

jbuendia829 - 7 days ago

Congrats on the launch!

Curious, it's a crowded space with other enterprise search companies like Glean and Elastic, and other companies coming in like Notion and Slack.

Why should a prospect choose Onyx over the others?

dberg - 8 days ago

how is this different from Librechat?

Der_Einzige - 8 days ago

Sorry, but why use this over oobabooga/sillytavern?

Why do we have to yet again poorly copy an oversimplified UI?

The value of local models comes from their huge amount of settings/control that they offer. Why must we throw that all away?

Yet again, the world waits for good UI/UX for pro/prosumers with AI systems. No one is learning from ComfyUI, Automatic1111, or SillyTavern. No, LM-Studio is not actually prosumer

thedangler - 7 days ago

If I'm understanding this right. I can train it on private data only for my company and then I can use the chat bot only for my site to acquire customers?

pablo24602 - 8 days ago

Congrats on the launch! Every enterprise deserves to use a beautiful AI chat UI (and Onyx is a fantastic and easy to try option).

novoreorx - 7 days ago

It's never too late to refine a common idea and take it to the next level. Congrats!

NullCascade - 7 days ago

Have you considered making a version that is packaged as a desktop app?

NickHoff - 7 days ago

Look neat. FYI clicking "See All Connectors" is a 404.

dackdel - 7 days ago

looks like https://github.com/block/goose

enoch2090 - 7 days ago

GW! How does Onyx differ from Open WebUI and its alike?

diebillionaires - 7 days ago

Seems like AnythingLLM

Axsuul - 7 days ago

Is this sort of like self-hosted NotebookLM?

awaseem - 8 days ago

This is awesome and love that its open source!

winddude - 7 days ago

why use a name, although spelled differently onyx vs onnx, that's already used and known in the ML/AI community?

mentalgear - 8 days ago

A bit like mastra.ai - my goto SOTA solution for these kind of LLM flow coordinations (though more dev-focused). (yes I realise this is more user-facing)

nawtagain - 8 days ago

Congrats on the launch!

Can you clarify the license and if this actually meets the definition of Open Source as outlined by the OSI [1] or if this is actually just source available similar to OpenWebUI?

Specifically can / does this run without the /onyx/backend/ee and web/src/app/ee directories which are licensed under a proprietary license?

1 - https://opensource.org/licenses

throw4039 - 7 days ago

Looks awesome! I'm really trying to switch off Open WebUI due to its general slowness and bugginess, as well as documentation which is almost entirely slop.

However it doesn't seem to have MinerU as a supported backend, which is hands-down the best PDF extraction tool I've ever used (and is self-hostable on a machine with a modest GPU). Could it be added?

https://github.com/opendatalab/MinerU

WhereIsTheTruth - 7 days ago

- can't branch-off/fork a chat

- can't fold/unfold code

- lack syntax highlight for some languages (Zig, Odin, D)

simianparrot - 7 days ago

... just because OpenAI call their product "ChatGPT" doesn't mean the term "chat" should now mean "interacting with an LLM".

KaoruAoiShiho - 8 days ago

I've been using Cherry Studio, works great.

hobofan - 7 days ago

Congrats on the launch!

We are building a competing open source tool[0] with a very similar focus (strongly relying on interoperable standards like MCP; built for enterprise needs, etc.), though bootstrapping with customers rather than being VC funded. It's nice to see a competitor in the field following similar "OSS Friends" principles, while many of the other ones seem to have strong proprietary tendencies.

(Small heads up: The "view all integrations" button goes to a 404)

[0] https://erato.chat/

symisc_devel - 7 days ago

Congratulations for the launch. Actually we launched a similar product recently named Vision Workspace (https://vision.pixlab.io). The general chat niche is quite saturated and practically locked by the major players. I recommend that you focus on one core feature and pivot from there. For us it was the built-in OCR and document query interface inside the UI that initiated the traction and the app is quite popular now in Japan and Malaysia.

turblety - 7 days ago

What is it with these Chat apps having strange and not-real open source licenses? OpenWebUI is the same. Is there something about these chat apps that seems to make them more prone to weird and strange licenses? Just opportunist?

_pdp_ - 8 days ago

> We’re building an open-source chat that works

As long as you have Pricing on your website your product is not open source in the true spirit of open sourceness. It is open code for sure but it is a business and so incentive is to run it like a business which will conflate with how the project is used by the community.

Btw, there is nothing wrong with that but let's be honest here if you get this funded (perhaps it already is) who are you going to align your mission with - the open source community or shareholders? I don't think you can do both. Especially if a strong competitor comes along that simply deploys the same version of the product. We have seen this story many times before.

Now, this is completely different from let's say Onyx being an enterprise search product where you create a community-driven version. You might say that fundamentally it is the same code but the way it is presented is different. Nobody will think this is open-source but more of "the source is available" if you want to check.

I thought perhaps it will benefit to share this prospective here if it helps at all.

Btw, I hear good things about Onyx and I have heard that some enterprises are already using it - the open-source version.

phildougherty - 8 days ago

Honestly surprised something like this can get funded

haolez - 7 days ago

[flagged]

polynomial - 7 days ago

Onyx?

And no one bothered to say anything to them?

zach_moore - 7 days ago

This was funded by YC? Why? It's more of a developer project/tool. It will become useless really quickly.