Velvet

Velvet was a developer gateway built to help engineering teams analyze, evaluate, and monitor AI-powered features running in production. Founded by Emma Lawler and Chris Hendel, the company focused on giving developers visibility into how their AI features behaved once deployed, rather than only during initial testing. In March 2025, Velvet was acquired by Arize AI, a company that builds a unified platform for AI evaluation and observability, and its founders joined Arize to help expand that platform. Through the acquisition, Velvet's evaluation and monitoring work now connects to Arize's broader ecosystem, including Phoenix, an open-source tool for tracing and evaluating large language model calls, and LiteLLM, a gateway that gives access to over 100 LLMs through a single OpenAI-compatible format while tracking spend and providing automatic fallbacks between models. Velvet is best suited for engineering teams building LLM-powered products who need a way to catch regressions and understand model behavior after launch, rather than teams looking for a no-code or business-user-facing tool. Because Velvet's own site and product are now folded into Arize's offering, prospective users evaluating it today are effectively evaluating Arize's combined platform rather than a standalone Velvet product.