PromptMetrics vs Vellum

PromptMetrics is a free, open-source, self-hosted prompt registry for managing prompt versions and observing LLM activity. Prompts can be stored, retrieved, and rolled back through a REST API or CLI, with changes recorded in Git. The system logs request metadata including model, tokens, latency, cost, and custom tags, and exports data to stdout JSON or OpenTelemetry. It also tracks agent traces, spans, workflow runs, and prompt versions labeled by environment. Evaluation suites can run against datasets with budget tracking, while A/B tests compare prompt versions and can promote a winner. A compliance scanner checks prompts for PII, API keys, URLs, and IP addresses, then assigns risk scores. Its playground can proxy calls for OpenAI, Anthropic, Cohere, Ollama, and Azure OpenAI. Prompt content can use filesystem, GitHub, or S3 storage; metadata can use SQLite or PostgreSQL. Interfaces include a REST API, CLI, optional Next.js dashboard, and Node.js and Python SDKs. Installation options include npm, Docker Compose, and building from source. The repository identifies the license as MIT.

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.