LangChain vs Vellum

LangChain is a free, MIT-licensed open-source framework for building agents with models and tools. Its create_agent harness combines a model, tools, prompt and middleware, with templates for common uses and a ReAct pattern. Middleware can add human approval, conversation compression, sensitive-data removal, guardrails, retries, routing and custom tool policies. Agents run on LangGraph’s durable runtime, which supports persistence, rewind, checkpointing and human-in-the-loop workflows. LangChain documents more than 1,000 integrations across chat and embedding models, tools, toolkits, document loaders and vector stores. Standard interfaces for chat models and embeddings support switching providers with minimal code changes. Documentation covers Python and JavaScript/TypeScript. LangSmith adds tracing, debugging and output evaluation. The framework supports API and self-hosted use. LangChain was started in 2023 and is headquartered in San Francisco.

Vellum is a personal AI assistant that can read files, manage calendars, send email, run code, and control a computer. It saves preferences and context in its workspace for later conversations, and users can create, install, and manage skills. Listed OAuth services include Discord, GitHub, Google services, HubSpot, Linear, Twitter (X), Asana, Notion, Microsoft Outlook, and Todoist. Vellum says OAuth tokens stay in a credential vault rather than being exposed to the language model. Sensitive actions prompt for approval, and users can set trust rules for standing permissions. By default, conversation context is sent to Anthropic to generate responses; OpenAI, Google, OpenRouter, Fireworks, and local Ollama are listed alternatives. An internet connection is required. Vellum Cloud runs assistants in isolated environments with private storage and 24/7 availability. The Free plan includes first tasks and pay-as-you-go credits. Mighty costs $30 a month, Super $100 a month, and Ultra $200 a month. There is no shipped Linux desktop client, but Linux users can use the web app, Chrome extension, or self-host the runtime.