Braintrust vs Weights & Biases Weave

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.

Weights & Biases (W&B) is a San Francisco-based MLOps and LLMOps platform founded in 2017. Weave is W&B's product layer purpose-built for LLM observability, evaluation, and governance. It provides automatic tracing of LLM calls (inputs, outputs, latency, cost), evaluation pipelines with human and automated scoring, dataset versioning, and guardrails to block prompt attacks and harmful outputs. Weave integrates with major LLM providers including OpenAI, Anthropic, Google Gemini, and frameworks such as LangChain and LlamaIndex. For AI compliance, W&B runs EU AI Act-focused webinar series demonstrating how Weave can generate compliance dossiers for high-risk AI systems, providing audit trails and evidence generation. The platform holds SOC 2 Type II certification. Enterprise tier includes SSO, RBAC, and private cloud deployment. W&B has raised $305M total and was valued at $1.25B in 2023.