Spanlens Reviews

Spanlens Description

Spanlens is an open-source observability platform licensed under MIT that enables developers to effectively track each interaction their applications have with services like OpenAI, Anthropic, Gemini, Mistral, OpenRouter, Azure OpenAI, or a local Ollama model. The integration process is incredibly simple, requiring just a single line of code to change the client's baseURL to the Spanlens proxy, or by executing "npx @spanlens/cli init," which prompts a wizard to automatically adjust your code. Once integrated, all requests are meticulously logged, capturing details such as the model used, token counts, latency, cost, and the complete prompt and response body, while also seamlessly reconstructing streaming responses.

The accompanying dashboard transforms this raw log data into actionable operational insights. Cost tracking functionality allows users to break down expenditures by individual requests, models, and end users, while also distinguishing prompt-cache tokens to provide clarity on actual savings rather than simply the total costs. Additionally, agent tracing presents multi-step workflows visually, using Gantt waterfalls and node-and-edge graphs to emphasize the critical path, enabling developers to pinpoint the slowest dependencies in a fan-out scenario. This comprehensive approach not only enhances visibility but also empowers users to optimize their model interactions for better efficiency and cost management.