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Langfuse vs Scribbler

Langfuse focuses on observability for LLM apps, not on in-browser notebooks.
LangfuseOpen Source Observability & Analytics for LLM Apps 🕵️‍♂️ScribblerUnleash JavaScript's Power: Experiment with Ease Using Notebooks!

Side by side

What it is
Langfuse:Langfuse is an open-source platform for tracing, evaluating and monitoring LLM applications and AI agents.
Scribbler:Scribbler is an in-browser, no-backend notebook for running JavaScript AI, data science, and visualization.
Best for
Langfuse:LLM observability & analytics
Scribbler:Client-side AI notebooks
Who it’s for
Langfuse:Developers building, debugging and scaling LLM-based apps and agents.
Scribbler:Developers and data scientists who want client-side AI without servers.
Pricing
Langfuse:Freemium
Scribbler:Free
Plans
Langfuse:Hobby Free · Core $29 per month · Pro $199 per month · Enterprise $2499 per month
Scribbler:—
Open source
Langfuse:Yes, 35,097 GitHub stars
Scribbler:Yes, 378 GitHub stars
Works with
Langfuse:Python, TypeScript, Go, Java, .NET, Ruby, PHP, Swift
Scribbler:TensorFlow.js, ONNX Runtime Web, Transformers.js, Plotly, D3, WebLLM, WebGPU
DevHunt upvotes
Langfuse:89
Scribbler:13
Launched on DevHunt
Langfuse:Jan 2023
Scribbler:Jan 2023

Langfuse features

  • Hierarchical Traces. Capture every LLM call, tool invocation and retrieval step with filters for user, session, cost and latency.
  • Prompt Management. Version, fetch, release and cache prompts separately from code with one-click deployments.
  • Evaluation Engine. Run LLM-as-judge, heuristic or human-review evaluations on production data or experiments.
  • Experiments & Datasets. Define test cases, run experiments and create golden datasets for continuous improvement.
  • Dashboards & Alerts. Monitor cost, latency and quality via custom dashboards and automated alerts.
  • Human Annotation. Collaborative human-in-the-loop workflows with annotation queues.
  • Extensive Integrations. Supports Python, TypeScript, Go, Java, .NET, Ruby, PHP, Swift and 100+ agent frameworks and model providers.
  • Self-hosted & Cloud Options. Available as hosted SaaS or self-hosted under MIT license.
Langfuse on DevHunt →Alternatives

Scribbler features

  • Zero-setup. Runs entirely in the browser; no install, login, or backend required.
  • WebGPU acceleration. Uses WebGPU for near-native performance on LLMs, image generation and ML inference.
  • Dynamic library loading. Import TensorFlow.js, ONNX Runtime, Transformers.js, Plotly, D3 and more from CDNs on demand.
  • Interactive notebooks. Mix JavaScript, HTML, CSS and Markdown in live cells with inline output.
  • Privacy-first. All computation stays on the device; no data leaves the browser.
  • Share & collaborate. Export notebooks as .jsnb files, share via URL, or push/pull directly to GitHub.
  • Self-hostable. Pure static files can be hosted on any web server, S3 bucket or GitHub Pages.
  • Built-in AI models. Run Stable Diffusion, LLM chat, and TTS via WebNN and ONNX Runtime in the browser.
Scribbler on DevHunt →Alternatives

Based on each tool's website and DevHunt data. Details may change; check the official sites.