Modular Prompt Library vs SpacePrompts
Modular Prompt Library
modularprompt.comSpacePrompts
spaceprompts.comSide by side
| Figure | Modular Prompt Library | SpacePrompts |
|---|---|---|
| Price from | $2.50/mo | $5/mo |
| Free plan | Yes | Yes |
| Free trial | Yes | — |
| Open source | — | — |
| Web | Yes | Yes |
| API | — | Yes |
| Plans published | 5 | 3 |
| Spec score · Prompt Management Software | 8.2 (#10) | 8.5 (#8) |
| Intended users | The site identifies AI content creation teams, prompt engineers, marketing agencies, software development teams, customer support teams, and educational institutions as audiences. | The maker describes SpacePrompts as serving people and teams who work with AI, including designers, writers, marketers, and API automation users. |
| Product | Modular Prompt Library is an AI prompt management platform for building, managing, sharing, testing, and comparing prompts. | SpacePrompts is a prompt management platform for saving, organizing, running, versioning, and reusing AI prompts. |
| Support | The site provides a support contact form for questions and help with the product. | The site directs users to a contact form and says replies typically arrive within 24 hours. |
| Team collaboration | Teams can share libraries, review changes, and collaborate on prompt development. | Team accounts provide a shared library, collaborative editing, invitations and Admin, Editor or Viewer roles. |
Plans
Modular Prompt Library
- Personal AccountFree
- StarterFree
- Growth$2.50 a month
- Professional$5 a month
- EnterprisePriced on request
In their own words
Modular Prompt Library
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.
SpacePrompts
SpacePrompts is a prompt management platform for people and teams working with AI. It runs on the web, through an API, and with Chrome, Edge, and Firefox extensions. Users can save, organize, run, version, and reuse prompts. The Playground combines an editor, variables, model selection, and immediate runs. An Evaluator scores prompts, highlights weak areas, and gives improvement guidance. Every save creates a version that can be restored later. The prompt manager extension can turn highlighted webpage text into a prompt. Its token counter supports OpenAI, Claude, Gemini, and DeepSeek models, showing token counts and estimated costs. Pro and Team plans provide API access, limited to 60 requests per minute per key. Team workspaces add shared libraries, collaborative editing, and role permissions for up to five members. Free includes 50 prompts and daily usage limits; Pro is $5 a month billed annually, and Team is $9 a month billed annually.