Prompt Management & Engineering Platform · Head to head

Langfuse vs LangSmith

Both products compete in Prompt Management & Engineering Platform. Prompt management and engineering platforms provide version control, deployment pipelines, A/B testing, evaluation tracking, and collaborative editing for the prompts that drive LLM-powered applications — treating prompts as first-class software artifacts rather than strings in a config file. Here are the facts the B4 Index maintains on each, side by side.

The two files, side by side

Langfuse

LangSmith

What it is

Open-source LLM observability with tracing, evaluation, and prompt management

LLM observability and evaluation platform from LangChain for tracing, testing, and monitoring

Website

langfuse.com ↗

smith.langchain.com ↗

Pricing

Free tier; from $20/mo; enterprise from $2,499/yr

Free limited tier; from $39/user/mo

Categories served

Prompt Management & Engineering Platform, LLM Observability & Agent Tracing Platform

Prompt Management & Engineering Platform, LLM Observability & Agent Tracing Platform, AI Model Evaluation (Evals) Platform

Status

Active · verified June 2026

The Langfuse file → The LangSmith file →

The decision underneath the comparison

Choosing between Langfuse and LangSmith assumes you're buying Prompt Management & Engineering Platform at all. That's the prior question, and the B4 Index scores it on two axes: how much Prompt Management & Engineering Platform differentiates you, and how far AI has come at building it. Read the build-versus-buy considerations for Prompt Management & Engineering Platform before you shortlist either product.

Vendor facts are maintained independently of any B4 verdict and re-verified on a monthly liveness check. See the full methodology.