π About Vellam
Vellum is an AI product development platform designed to help engineering and product teams build, test, and deploy large language model (LLM) powered applications with greater confidence and speed. The platform was built by the Vellum team, co-founded by Nate Sesti and other AI-focused engineers, and launched in 2023 to address the growing complexity of taking LLM applications from prototype to production. It targets companies that need more than just an API connection β teams that require systematic workflows for prompt management, evaluation, and deployment.
The technology behind Vellum works by giving you a structured environment where you can design and chain together LLM workflows using a visual node-based editor, connect to models from providers like OpenAI, Anthropic, and Cohere, and run those pipelines against real data. You can version your prompts, test variations against regression suites, and track quality metrics over time without writing custom evaluation infrastructure from scratch. Vellum abstracts away much of the orchestration complexity while still giving developers direct control over model parameters, context windows, and decision logic at each step.
Among Vellum's standout features, its Prompt Sandbox lets you run side-by-side comparisons of different prompts and models, scoring outputs against custom criteria so you can make data-driven decisions before shipping. Its Test Suites feature allows you to define evaluation datasets and automatically check new prompt or model changes against historical performance benchmarks, catching regressions before they reach production. Additionally, Vellum's Document Indexes provide a managed vector store so you can build retrieval-augmented generation (RAG) pipelines directly within the platform without needing to set up and maintain a separate vector database.
Vellum operates on a freemium model, offering a free tier that gives smaller teams and individual developers access to core prompt management and sandbox features with limited usage. Paid plans start at the Starter and Growth tiers, which unlock higher API call volumes, team collaboration features, advanced evaluations, and priority support, making them suited for startups scaling their LLM products. Enterprise plans offer custom pricing, dedicated infrastructure, SSO, and compliance features for larger organizations with strict security and data governance requirements.
By 2026, Vellum has become a trusted tool among AI product teams at Series A through Series C startups as well as enterprise innovation labs that need to move fast without sacrificing reliability. You can find it used by teams building customer support bots, document processing pipelines, and intelligent search experiences, where consistent output quality directly affects user satisfaction. Companies report measurably shorter iteration cycles on prompt engineering and fewer costly model-related incidents in production, making Vellum a core part of the modern AI development stack.
