Arize AI vs Braintrust

Arize AI is an LLM observability and evaluation platform designed for enterprises running AI agents and LLM applications at scale. Its flagship product, Arize AX, provides real-time monitoring, agent tracing, prompt management, online evaluations using LLM-as-a-Judge, and drift detection across NLP, computer vision, and multimodal models. The company also maintains Arize Phoenix, a widely adopted open-source AI observability library built on OpenTelemetry/OpenInference standards.

Braintrust is an AI observability and evaluation platform that enables teams to monitor production AI applications, evaluate output quality, and iterate on prompts and models systematically. Key differentiators include integrated tracing, evals, and monitoring in one system; Brainstore database optimized for AI traces with superior query speed; Loop AI agent for generating prompts and scorers; and flexible integrations via SDKs, OpenTelemetry, and AI Proxy. Typical buyers are engineering and product teams at tech companies building AI agents or LLM apps, such as Notion, Replit, and Coursera. In February 2026, it raised $80M Series B at $800M valuation, signaling strong investor confidence in AI observability infrastructure. Enterprise features support compliance with SOC 2 Type II, GDPR, and HIPAA.