Modular Prompt Library vs PromptForge

Modular Prompt Library is a web platform for building, managing, sharing, testing, and comparing AI prompts. Users can assemble prompts from reusable components and use them across projects. Version history records changes and supports returning to an earlier version, while shared libraries let teams review and collaborate on prompt work. For testing, users connect their own OpenAI, Anthropic, or Google API keys, fill prompt variables, adjust temperature, top-p, and max tokens, and save presets for a prompt version. The comparison environment displays outputs side by side with latency, token counts, and estimated cost. The site says keys are encrypted at rest, usage is billed directly by the model provider, and prompts, variables, and outputs remain in the user's workspace. Personal Account is free for personal use, with up to five workspaces and unlimited prompts and modules. Starter is free for up to five users or three workspaces; Growth costs $2.50 a month and Professional costs $5 a month. Organizational accounts have a 60-day free trial, and no credit card is required to start.

PromptForge manages AI prompt templates and makes them available through a REST API. It is aimed at AI developers who want to update prompt text without redeploying application code. Templates can include reusable placeholders using {{variable}} syntax. Each edit creates an immutable version, and users can compare line-by-line changes and roll back. Applications can request a stable, latest, or specific prompt version; API requests use Bearer token authentication and GET or POST methods. Listed integrations include OpenAI, Anthropic Claude, Google Gemini, Grok, Groq, Mistral, Vercel AI SDK, Ollama, Cohere, Together AI, Azure OpenAI, and AWS Bedrock. PromptForge stores, organizes, versions, and shares text prompts; it does not perform AI generation, analysis, or training. The free Hobby plan is billed forever and allows one production prompt and 1,000 API requests per month. Starter costs $9 a month, Pro $29 a month, and Business $49 a month. The terms state that there is no export feature or formal SLA or uptime credits.