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Products that do what Spanlens does

Open-source LLM observability in one line of code

  1. 1

    Trace LLM requests + costs with OpenTelemetry monitoring

    Oct 2025

  2. 2OO

    Hey HN, Nir, Gal and Tomer here. We’re open-sourcing a set of extensions we’ve built on top of OpenTelemetry that provide visibility into LLM applications - whether it be prompts, vector DBs and more. Here’s the repo: https://github.com/traceloop/openllmetry. There’s already a decent number of tools for LLM observability, some open-source and some not. But what we found was missing for all of them is that they were closed-protocol by design, vendor-locking you to use their observability platform or their proprietary framework for running your LLMs. It’s still early in the…

    2023 · github.com

  3. 3NW

    Hey HN, Henry here from Cactus. We open-sourced Needle, a 26M parameter function-calling (tool use) model. It runs at 6000 tok/s prefill and 1200 tok/s decode on consumer devices. We were always frustrated by the little effort made towards building agentic models that run on budget phones, so we conducted investigations that led to an observation: agentic experiences are built upon tool calling, and massive models are overkill for it. Tool calling is fundamentally retrieval-and-assembly (match query to tool name, extract argument values, emit JSON), not reasoning. Cross-attention…

    May 2026 · github.com

  4. 4
    Langfuse771

    Open source tracing and analytics for LLM applications

    2023 · langfuse.com

  5. 5YD

    If you've built any web-based app in the last 15 years, you probably used something like Datadog, New Relic, Sentry, etc. to monitor and trace your app, right? Why should it be different when the app you're building happens to be using LLMs? So today we're open-sourcing OpenLLMetry-JS. It's an open protocol and SDK, based on OpenTelemetry, that provides traces and metrics for LLM JS/TS applications and can be connected to any of the 15+ tools that already support OpenTelemetry. Here's the repo: https://github.com/traceloop/openllmetry-js A few months ago we launched…

    2024 · github.com

  6. 6
    Openlit152

    One click observability & evals for LLMs & GPUs

    2024

  7. 7
    traceAI273

    Open-source LLM tracing that speaks GenAI, not HTTP.

    Apr 2026 · github.com

  8. 8OO

    Hey HN, we're super excited to share something we've been working on: OpenLIT. After an engaging preview that some of you might recall, we are now proudly announcing our first stable release! *What's OpenLIT?* Simply put, OpenLIT is an open-source tool designed to make monitoring your Large Language Model (LLM) applications straightforward. It’s built on OpenTelemetry, aiming to reduce the complexities that come with observing the behavior and usage of your LLM stack. *Beyond Basic Text Generation:* OpenLIT isn’t restricted to just text and chatbot outputs. It now includes automatic…

    2024 · github.com

  9. 9
    LLMonitor128

    Open source monitoring and production toolkit for AI apps

    2023

  10. 10IW

    Hey HN, I made Browser-Use, an open-source tool that lets (all Langchain supported) LLMs execute tasks directly in the browser just with function calling. It allows you to build agents that interact with web elements using natural language prompts. We created a layer that simplifies website interaction for LLMs by extracting xPaths and interactive elements like buttons and input fields (and other fancy things). This enables you to design custom web automation and scraping functions without manual inspection through DevTools. Hasn't this been done a lot of times? Good question, as a general…

    2024 · github.com

  11. 11

    One line of code, Full AI visibility.

    Jun 2026 · llm-watch.vercel.app

  12. 12

    AI-driven observability for $0.20 per GB

    2024

  13. 13OS

    Hi HN, Hugh and Vince here. LLMonitor helps you record, trace & search your LLM queries and chatbot conversations. You can also capture user feedback on your frontend and correlate it with backend LLM queries then use that to fine-tune your own models. The project started has an internal tool in our previous (failed) AI startup. We’re aware the LLM observability space is very crowded. Apart from being open-source, we differentiate with: - Model-agnostic and minimal lock-in (no MITM of requests). - High focus on DX and dashboard clarity. - Support for complex scenarios: e.g. a chatbot that…

    2023 · github.com

  14. 14

    Aggregate uptime monitoring across OpenAI, Claude, and more

    Apr 2026 · tools.lamatic.ai

  15. 15

    Open-source LLM tracing for agent visibility

    Mar 2026 · breadcrumb.sh

  16. 16
    Openlayer197

    Slack or email alerts for when your AI fails

    2023

  17. 17
    FlowLens134

    Bug reports built for coding agents, so you can ship faster.

    Dec 2025

  18. 18
    TraceLLM100

    OpenTelemetry for production AI applications

    Jul 2026 · tracellm.in

  19. 19LO

    Hi HN! Langfuse is OSS observability and analytics for LLM applications (repo: https://github.com/langfuse/langfuse, 2 min demo: https://langfuse.com/video, try it yourself: https://langfuse.com/demo) Langfuse makes capturing and viewing LLM calls (execution traces) a breeze. On top of this data, you can analyze the quality, cost and latency of LLM apps. When GPT-4 dropped, we started building LLM apps – a lot of them! [1, 2] But they all suffered from the same issue: it’s hard to assure quality in 100% of cases and even to have a clear view…

    2023 · github.com

  20. 20LO

    Hey HN, we’re Robert, Din and Temirlan from Laminar (https://www.lmnr.ai), an open-source observability and analytics platform for complex LLM apps. It’s designed to be fast, reliable, and scalable. The stack is RabbitMQ for message queues, Postgres for storage, Clickhouse for analytics, Qdrant for semantic search - all powered by Rust. How is Laminar different from the swarm of other “LLM observability” platforms? On the observability part, we’re focused on handling full execution traces, not just LLM calls. We built a Rust ingestor for OpenTelemetry (Otel) spans with GenAI…

    2024 · github.com

  21. 21OS

    Hi everyone, we’re a small team, supported by Mozilla, who are working on re-imagining a UI for training, tuning and testing local LLMs. Everything is open source. If you’ve been training your own LLMs or have always wanted to, we’d love for you to play with the tool and give feedback on what the future development experience for LLM engineering could look like.

    2025 · github.com

  22. 22

    Real-time observability dashboard for OpenClaw AI agents

    Feb 2026

  23. 23
    Mi75

    30-line zero-config CLI agent for bug fixes + refactoring

    May 2026 · github.com

  24. 24
    Taylor AI118

    Fine-tune open source LLMs in minutes

    2023

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