PromptForge vs Vellum

PromptForge is a web and API platform for building, testing and deploying multimodal prompts. Its workbench includes chat, image and video, speech, transcription and embeddings modes, with a model catalog, streaming previews and version history. Teams can batch-test prompts on datasets using evaluators, A/B tests and scheduled regression runs. Release gates enforce a configured pass-rate threshold through the app, APIs or CLI tools, including GitHub Actions. Versioned deployments offer environment pins, invoke URLs, optional schedule guards and API keys. A visual builder links prompt steps, HTTP calls and logic into versioned flows. Production and test logs provide cost, latency and quality signals. The media library stores uploaded and generated images, video and audio with metadata, bulk actions and links to prompts. BYOK connections support providers including OpenAI, Anthropic and Google. The free plan is free for one user, three projects, 200 test runs monthly and 1 GB storage.

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.