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Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

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Re: Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

#31

Congrats Marc! We've been using Langfuse for about 6-months for our LLMOps tooling. While its SDKs are limited to python and typescript, their openapi specification is pretty easy to implement in any language. The team behind it is amazing, and their product being OSS is one of the reasons we chose it. But it just keeps getting better. We're incidentally only using part of the product because we've implemented most o…

Thanks for the feedback.

Being unopinionated and API-first has been a core design decision. We want to build the building blocks that everyone needs while acknowledging that most Langfuse users are very sophisticated teams that have a clear idea of what they want to achieve. Over time we will build more abstractions for common workflows to make it easier to get started but new features will always start API-first.

More on this here: https://langfuse.com/why

Re: Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

#32
I've been using self hosted langfuse via litellm in a juptyer notebook for a few weeks for some synthetic data experiments. It's been a nice/useful tool.

I've liked having the traces and scores in a unified browser based UI, it made sanity checking experiments way easier than doing the same thing inside the notebook.

The trace/generation retrieval API was brutally slow for bulk scanning operations, so I bypassed it and just queried the db directly. But the is the beauty of open source/self hosted code.

Re: Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

#33
post #29

(unsolicited review) we've been happy adopters of LangFuse at AINews ( https://smol.ai/news ). ive been tracking the llm ops landscape ( https://www.latent.space/p/braintrust ) for a while and its very nice to have an open source solution that is so comprehensive and intuitive! reflections/thoughts on where this field goes next: 1. i wonder if there are new ops solutions for the realtime apis popping up 2. retries fo…

appreciate your constructive feedback!

> i wonder if there are new ops solutions for the realtime apis popping up

This is something we have spent quite some time on already, both on designs internally and talking to teams using Langfuse with realtime applications. IMO the usage patterns are still developing and the data capturing/visualization needs across teams is not aligned. What matters: (1) capture streams, (2) for non-text provide timestamped transcript/labels, (3) capture the difference between user-time and api-level-time (e.g. when catching up on a stream after having categorized the input first).

We are excited to build support for this, if you or others have ideas or a wishlist, please add them to this thread: https://github.com/orgs/langfuse/discussions/4757

> retries for instructor like structured outputs mess up the traces, i wonder if they can be tracked and collapsible

Great feedback. Being able to retroactively downrank llm calls to be `debug` level in order to collapse/hide them by default would be interesting. Added thread for this here: https://github.com/orgs/langfuse/discussions/4758

> chatgpt canvas like "drafting" workflows are on the rise (https://www.latent.space/p/inference-fast-and-slow) and again its noisy to see in a chat flow

Can you share an example trace for this or open a thread on github? Would love to understand this in more detail as I have seen different trace-representations of it -- the best yet was a _git diff_ on a wrapper span for every iteration.

> how often do people actually use the feedback tagging and then subsequently finetuning? i always feel guilty that i dont do it yet and wonder when and where i should.

Have not seen finetuning based on user-feedback a lot as the feedback can be noisy and low in frequency (unless there is a very clear feedback loop built into the product). More common workflow that I have seen: identify new problems via user feedback -> review them manually -> create llm-as-a-judge or other automated evals for this problem -> select "good" examples for fine-tuning based on a mix of different evals that currently run on production data -> sanitize the dataset (e.g. remove PII).

Finetuning has been more popular for structured output, sql generation (clear feedback loop / retries at run-time if the output does not work). More teams fine-tune on all the output that has passed this initial run-time gate for model distillation without further quality controls on the training dataset. They usually then run evals on a test dataset in order to verify whether the fine-tuned hits their quality bar.

Re: Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

#34

I've been using self hosted langfuse via litellm in a juptyer notebook for a few weeks for some synthetic data experiments. It's been a nice/useful tool. I've liked having the traces and scores in a unified browser based UI, it made sanity checking experiments way easier than doing the same thing inside the notebook. The trace/generation retrieval API was brutally slow for bulk scanning operations, so I bypassed it a…

Thanks for the feedback, glad that you find Langfuse useful!

Can you create an issue with more details on the API performance problems? We monitor strict SLOs on the public API for Langfuse Cloud and are not aware of any ongoing issues, would love to learn more.

Re: Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

#36

Have been a very happy Langfuse user since March - dead simple to use and has helped us a lot with LLM observability and debugging - great work guys :))

thank you! if you have any ideas for improvements after having used Langfuse for a while, please contribute them via github discussions: https://langfuse.com/ideas

Re: Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

#37
post #6

Earlier quoted context omitted.

What are other potential platforms?

Bunch of them : Langsmith, Lunary, Phoenix Arize, Portkey, Datadog and Helicone. We also picked Langfuse - more details here: https://www.nonbios.ai/post/the-nonbios-llm-observability-pi...

Thanks for sharing your blogpost. We had a similar journey. I installed and tried both Langfuse and Phoenix and ended up choosing Langfuse due to some versioning conflicts on the python dependency. I’m curious if your thoughts change after V3? I also liked that it only depended on Postgres but the scalable version requires other dependencies.

The thing I liked about Phoenix is that it uses OpenTelemetry. In the end we’re building our Agents SDK in a way that the observability platform can be swapped (https://github.com/zetaalphavector/platform/tree/master/agen...) and the abstraction is OpenTelemetry-inspired.

Re: Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

#38

Congrats on the launch :) happy users @ Samsara. Key to our LLM customer feedback flywheel and dataset building.

Thank you! Working with your team has been great. I love seeing you ship LLM-powered features and appreciate the feedback you have shared along the way.

Re: Launch HN: Langfuse (YC W23) – OSS Tracing and Workflows to Improve LLM Apps

#40
A happy Langfuse customer here!

We've been building an agent platform and some of our customers wanted someway to exfil OTEL traces to their own setup. Initially we tried building our own but then realised Languse does exactly what we needed doing. So we offered it as a first class integration, (and started using it internally).

Great product, and hope you guys continue to improve it!

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