Vellum is a developer platform founded in January 2023 by Akash Sharma, Noa Flaherty, and Sidd Seethepalli. It is purpose-built for teams building applications powered by large language models (LLMs), helping them bring features from prototype to production efficiently. Vellum offers a comprehensive suite of tools including prompt engineering, semantic search, performance monitoring, and fine-tuning, as well as a visual builder, SDK, and observability features.

The platform integrates with models from leading providers like OpenAI, Anthropic, Cohere, Google, and MosaicML. Its goal is to eliminate the repetitive setup work and enable teams—technical and non-technical alike—to collaborate on building reliable, scalable AI workflows. With features like real-world feedback capture and integrated evaluations, Vellum supports test-driven AI development and multi-model orchestration.

Vellum has raised $5.12 million across two seed rounds, most recently a $5 million round in July 2023. Notable investors include Y Combinator, Eastlink Capital, Pioneer Fund, Rebel Fund, and Twenty Two Ventures. The company is headquartered at 169 Madison Avenue, Unit 2323, New York, NY 10016, with a secondary office in San Francisco, CA. As of April 2025, Vellum has between 11 and 50 employees, with an engineering team of around 12 people. The company continues to expand its capabilities to support modern AI teams in shipping faster and with more confidence.