Originally published on NextFuture

Picking the best LLM observability tools used to mean choosing between a Datadog dashboard hacked into your prompt logs or a homegrown SQLite trace viewer. In 2026 you have seven serious platforms, four of them open source, and pricing that starts at zero. This post benchmarks the tools I run in production for a Claude API + RAG stack: tracing depth, eval support, self-hosting, OpenAI-compatible proxying, and what a real bill looks like at 5M spans/month.

TL;DR: The 2026 winners

If you only read the table, here is which tool I would integrate this week by use case.…