Evals

Concept

Evals Explained

Evals are the unit tests of AI systems. Without them you're flying blind. Here's how to build a useful eval set without going overboard.

Tool Guide

Braintrust Guide

The definitive guide to Braintrust for AI evals and observability — traces to experiments, GitHub Action CI, scoring UX, and when to pick Langfuse instead.

Tool Guide

Langfuse Guide

The definitive guide to Langfuse for LLM observability — traces, prompt versions, evals, cost tracking, self-host setup, and when to pick it over Braintrust or Phoenix.

Comparison

Langfuse vs Braintrust vs Phoenix

Three observability options for production LLM apps — open-source tracing, eval-first SaaS, and RAG-focused OSS from Arize.

Interview

How would you build an evaluation suite for an LLM-powered feature?

Evals are the difference between shipping and praying. Standard interview topic in 2026.

Interview

Design an internal platform for running LLM evals at scale.

Tests AI infrastructure thinking — increasingly relevant as companies build AI platforms.