OpenAI Playground vs Vellum
OpenAI Playground
platform.openai.comVellum
vellum.aiSide by side
| Figure | OpenAI Playground | Vellum |
|---|---|---|
| Price from | — | $30/mo |
| Free plan | — | Yes |
| Free trial | — | — |
| Open source | — | Yes |
| Web | Yes | Yes |
| Windows | — | Yes |
| macOS | — | Yes |
| iOS | — | Yes |
| Android | — | Yes |
| API | — | Yes |
| Self-hosted | — | Yes |
| Plans published | 0 | 9 |
| Spec score · Prompt Engineering Tools | 5.6 (#24) | 8.6 (#6) |
| Headquarters | San Francisco, California, United States | United States |
Plans
Vellum
- BaseFree
- FreeFree
- Mighty$30 a month
- Mighty$30 a month
- Custom$50 a month
- Super$100 a month
- Super$100 a month
- Ultra$200 a month
- Ultra$200 a month
In their own words
OpenAI Playground
OpenAI Playground has no write-up on Specifiction yet; its figures are above.
Vellum
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.