Modular Prompt Library vs PromptHelm
Modular Prompt Library
modularprompt.comPromptHelm
prompthelm.appSide by side
| Figure | Modular Prompt Library | PromptHelm |
|---|---|---|
| Price from | $2.50/mo | $39/mo |
| Free plan | Yes | Yes |
| Free trial | Yes | Yes |
| Open source | — | — |
| Web | Yes | Yes |
| iOS | — | Yes |
| Android | — | Yes |
| API | — | Yes |
| Self-hosted | — | Yes |
| Plans published | 5 | 4 |
| Spec score · Prompt Management Software | 8.2 (#10) | 9.0 (#5) |
| 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 documentation identifies engineering teams shipping LLM features, platform teams consolidating provider keys and reporting, and builders who want rigorous prompt history as intended users. |
| Product | Modular Prompt Library is an AI prompt management platform for building, managing, sharing, testing, and comparing prompts. | PromptHelm describes itself as a prompt management platform for LLM engineering teams to version, deploy, and monitor prompts across providers. |
| Support | The site provides a support contact form for questions and help with the product. | Listed support ranges from community on Free to email with a 48-hour response on Pro, priority plus Slack on Business, and a dedicated SE on Enterprise. |
| Trial | Organizational accounts have a 60-day free trial for all tiers, and the site says no credit card is required to start. | Every new account gets an automatic 14-day Pro trial with no credit card required. |
Plans
Modular Prompt Library
- Personal AccountFree
- StarterFree
- Growth$2.50 a month
- Professional$5 a month
- EnterprisePriced on request
PromptHelm
- FreeFree
- Pro$39 a month
- Business$249 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.
PromptHelm
PromptHelm is a prompt management platform for engineering teams building LLM features. It supports deploying prompts by environment, keeping version histories, rolling back changes, and testing in a playground. Its multi-provider gateway names OpenAI, Anthropic, Google, and DeepSeek. Teams can track token spending by model and prompt, review usage and cost trends, and set budget alerts. Request monitoring filters by status, model, or prompt and provides request and response details for debugging; analytics cover P50/P95/P99 latency, error rates, and model performance comparisons. SDKs are listed for Node, Python, iOS, Android, Java, and.NET. Plans include a free tier, Pro at $39 a month, and Business at $249 a month; Enterprise pricing is custom and unlisted. New accounts receive an automatic 14-day Pro trial without a credit card. The documentation describes access as invite-only, with private-beta invitations rolling out weekly.