Spanlens Pricing 2026

Spanlens is a freemium ai agent infrastructure tool that offers 6 key features including One-line instrumentation via a CLI that rewrites your call sites, Request logging with cost, latency and token counts for OpenAI, Anthropic and Gemini, Agent workflow tracing in a Gantt view. Spanlens is an MIT-licensed LLM observability platform whose main design goal is that instrumenting an application should cost one line rather than an afternoon. A CLI initialiser rewrites the call sites for you, after which every OpenAI, Anthropic and Gemini request is logged with its cost, latency and token counts, and multi-step agent workflows are traced into a Gantt view that shows where the time and money actually went. Beyond straight logging it runs three checks that most cost dashboards do not: anomaly detection on a three-sigma basis, PII and prompt-injection detection on request content, and a model recommendation pass that proposes cheaper models with a dollar-figure saving attached rather than a vague suggestion. Recent SDK releases added Ollama support for local models and LangGraph tracing, so self-hosted and graph-structured agent stacks are covered alongside the hosted APIs. The licensing position is the sharpest part of the pitch: the vendor states the project is fully MIT with no `ee/` folder, meaning there is no enterprise-only directory carved out of the open-source repository — self-host with Docker Compose and every feature listed on the paid tiers is available at zero cost. The hosted tiers exist to sell managed retention, seats and alerting rather than to gate functionality, and the site publishes direct comparisons against Langfuse and Helicone.

✅ Spanlens is a good choice if you need:

• •One-line instrumentation via a CLI that rewrites your call sites
• •Request logging with cost, latency and token counts for OpenAI, Anthropic and Gemini
• •Agent workflow tracing in a Gantt view
• •PII and prompt-injection detection on request content
• •Three-sigma anomaly detection and cheaper-model recommendations with dollar savings

💡 Value Assessment

With a free tier available, Spanlens is an easy recommendation for anyone looking to try ai agent infrastructure tools without financial commitment. The paid plans offer good value for power users who need the additional features and higher usage limits.