Vellum
by Vellum AI
Platform to build, evaluate, and deploy LLM apps and AI agents
Last reviewed 2026-06-18
Vellum is an end-to-end AI development platform that takes LLM products from idea to production, with tooling for experimentation, evaluation, deployment, monitoring, and collaboration. Its core surface is a prompt-engineering playground for comparing prompts across open and closed models, a visual workflow builder where nodes are LLM calls, code, conditionals, API calls, and RAG, an evaluations framework for asserting on outputs, one-click deployments, and production monitoring. It ships an agent builder where an Agent Node connects to tools (code, subworkflows, Composio SaaS integrations, and MCP servers) with auto-generated schemas. Vellum is model-agnostic across many providers and serves product and engineering teams building production LLM features and agents. (Note: at the time of this review, the apex vellum.ai domain appeared to serve an unrelated product, with the platform's canonical surface on its docs.)
What it can do
Engineer and compare prompts
AssistantA playground for testing prompts across open and closed models side by side, with versioning.
sourceBuild visual LLM workflows
SupervisedA node-based builder where nodes are LLM calls, code, conditionals, API calls, and RAG, assembling chatbots, RAG apps, and agents.
sourceEvaluate and test LLM outputs
AssistantAn evaluations framework that runs assertions on intermediate and final outputs via test banks and custom or LLM-based metrics.
sourceBuild and deploy tool-using agents
SupervisedAn Agent Node connects to code, subworkflows, Composio integrations, and MCP servers, with auto-generated tool schemas, then deploys to an API.
source
Strengths
- +Genuinely model-agnostic with a large, frequently updated catalog, avoiding lock-in
- +Covers the full LLM lifecycle (experiment, evaluate, deploy, monitor) in one place
- +Strong agent tooling with first-class MCP, Composio integrations, and auto-generated function-calling schemas
Limitations
- −Brand and domain confusion: the apex vellum.ai domain appeared to host an unrelated product at this review
- −Platform pricing is not transparently published (sales-led, enterprise-leaning)
- −Adds an abstraction layer and vendor dependency versus building directly on provider SDKs
Overview
Vellum is an end-to-end platform for building, evaluating, deploying, and monitoring LLM applications and AI agents. It is model-agnostic and aimed at product and engineering teams shipping production LLM features.
What it does
The core surface includes a prompt-engineering playground for side-by-side model comparison, a visual workflow builder (LLM calls, code, conditionals, API, RAG), an evaluations framework with test banks and custom metrics, one-click deployment to an API, and monitoring. Its agent builder's Agent Node connects to code, subworkflows, Composio integrations, and MCP servers with auto-generated schemas. It ships human-in-the-loop by default via evaluation gates and explicit deploy steps.
Integrations & setup
Model-agnostic across 20+ providers (OpenAI, Anthropic, Gemini, Bedrock, and more), with Composio for SaaS tool actions and MCP support both as a client and a server.
Pricing
Not transparently published at this review; sales-led and enterprise-leaning. A free or low tier has historically existed.
Best for / not for
Best for teams that want one platform spanning experimentation through production monitoring and prefer not to lock into a single model. Teams comfortable building directly on provider SDKs may not need the abstraction.
Alternatives
Dify, Stack AI, and Langflow are comparable agent-building platforms.
What people are saying
We aggregate real LinkedIn discussion into sentiment for the agents people search most. Vellum isn't tracked yet, want it added? Request tracking.
FAQ
What is Vellum for?+
Building, evaluating, deploying, and monitoring LLM applications and AI agents. It provides a prompt playground, a visual workflow builder, an evaluation framework, one-click deployments, and production monitoring.
Does Vellum support MCP?+
Yes. Its Agent Node can connect to MCP servers as tools, and Vellum exposes its own MCP server so assistants like Claude Code and Cursor can work with it.
Sources
- Vellum docs: product overview · accessed 2026-06-18
- Built-in tool calling for complex agent workflows (Vellum blog) · accessed 2026-06-18
- Announcing our $20M Series A (Vellum blog) · accessed 2026-06-18
- Vellum (Y Combinator profile) · accessed 2026-06-18
Last reviewed 2026-06-18