Langfuse significantly outpaces Spanlens in community adoption with 32,131 stars compared to 10 stars on GitHub. This 3213.1x difference suggests Langfuse has a much larger and more active community. In terms of developer contributions, Langfuse has 3,442 forks, indicating strong developer engagement.

Both projects show recent activity, with Langfuse last updated 18 hours ago and Spanlens 14 hours ago.

Langfuse has been in development longer, starting 3 years ago, compared to Spanlens which began 3 months ago. This 3.0-year head start suggests Langfuse may have more mature features and established processes.

Spanlens is licensed under MIT, while Langfuse's license terms are not publicly specified.

Both tools serve similar use cases in LLM Observability & Evaluation.

Both Langfuse and Spanlens offer self-hosting capabilities, giving you full control over your data and infrastructure.