Promptmetheus
ChatGPT prompt engineering toolkit. [Free]
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What is Promptmetheus?
Promptmetheus is a prompt engineering IDE for building, testing, optimizing, and deploying prompts for LLM-powered apps, agents, workflows, and automations. It is designed to help users compose prompts from structured sections, compare variants, and improve reliability through testing and evaluation.
The tool breaks prompts into LEGO-like blocks such as Context, Task, Instructions, Samples, and Primer, making it easier to iterate on each part independently. It also supports prompt variables, custom evaluators, datasets, completion ratings, model parameter tuning, and performance visualization so users can understand what is working and why.
Promptmetheus is aimed at people who need predictable LLM outputs, including product builders, prompt engineers, AI developers, and teams collaborating on AI workflows. The website emphasizes traceability, statistics, and repeatable experimentation, which makes it especially useful for production-oriented prompt design rather than casual chat use.
It supports testing against many providers and models, offers export and collaboration features, and includes workspace options for individuals and teams. The product also positions itself as a place to manage prompt libraries, track changes, and estimate costs while working with your own API keys.
Promptmetheus pricing
Pricing model: Freemium
Promptmetheus offers a free Playground tier and paid plans for individuals and teams. The Playground plan is free and includes Forge, 1 user, local data storage, OpenAI models, Stats & Insights, data import/export, and community support. The Single plan costs $29 per month, includes a 7-day free trial, and adds the Prompt IDE, cloud sync between devices, 15 providers and 150+ models, multiple projects, automatic evaluators, prompt history and full traceability, Stats & Insights, data export, and dedicated support. The Team plan costs $99 per month, includes 3 users, adds $19 per extra user, and includes all Single features plus user management, a shared workspace with real-time collaboration, and business support. Subscriptions do not include inference spend, so users must supply their own API keys. Enterprise plans and special requests are available by contacting the company.
Promptmetheus pros
- Structured prompt blocks
- LEGO-like prompt composition
- Prompt variable support
- Custom prompt evaluators
- Test datasets for iteration
- Completion ratings
- Visual performance statistics
- Cost calculation for completions
- Full prompt traceability
- Versioning and changelogs
- Stats and insights dashboard
- Real-time sync for teams
- Shared team workspaces
- Prompt library management
- Export to .txt, .csv, .xlsx, and .json
- Supports 15 APIs and 150+ LLMs
- Model catalog for provider comparison
- Works for apps, agents, workflows, and automations
- No-code prompt development focus
- Local data storage in the free tier
Promptmetheus cons
- Requires a 12-inch or larger screen
- Subscriptions do not include inference credits
- You must provide your own API keys
- Free tier is limited to one user
- Free tier uses local data storage only
- Team plan starts at three users
- No refund policy
- Forge history cannot be recovered after migration
- Archery to Forge migration is not possible
- Some support is routed through documentation first
- Enterprise pricing is not listed publicly
- Open-source status is not offered
- Real-time collaboration requires a paid team plan
- Cloud sync is not included in the free tier
- Advanced automation support is not spelled out in detail
Frequently asked questions about Promptmetheus
What does Promptmetheus do?
Promptmetheus is a prompt engineering IDE for composing, testing, optimizing, and deploying prompts for LLM-powered apps, agents, workflows, and automations. It is built for users who want structured prompt development, model comparison, evaluation, and traceability rather than simple one-off chatting.
How does prompt composition work in Promptmetheus?
Promptmetheus breaks prompts into structured blocks so you can work on pieces like Context, Task, Instructions, Samples, and Primer separately. This lets you create variants for each section and fine-tune prompts systematically instead of editing a single long text field.
What can I test inside the platform?
You can test prompts with datasets, compare completions across models and parameters, and use completion ratings to judge quality. The platform also provides visual statistics so you can see how different prompt blocks and variants perform.
What models and providers are supported?
The website says Promptmetheus can test prompts with 15 APIs and 150+ LLMs, and it lists many providers such as Anthropic, OpenAI, Google DeepMind, Mistral, Perplexity, xAI, DeepSeek, Cohere, and others. It also supports custom models that are compatible with the OpenAI API or LiteLLM SDK.
Does Promptmetheus support collaboration?
Yes. The site says Team accounts include shared workspaces for real-time collaboration, user management, and a shared prompt library. Private workspaces are available for individual users as well.
What export formats are available?
Promptmetheus can export prompts and completions in .txt, .csv, .xlsx, and .json formats. The site also mentions data import/export in the free tier and export features in the paid plans.
How is pricing structured?
There is a free Playground plan, a Single plan at $29 per month, and a Team plan at $99 per month. The Single plan includes a 7-day free trial, while the Team plan includes 3 users and charges $19 per month for each additional user.
Do I need to pay for model usage separately?
Yes. The website states that subscriptions do not include a budget for inference, so you must provide your own API keys. That means model usage costs are separate from the Promptmetheus subscription.
Can I use Promptmetheus without code?
The site positions Promptmetheus as a no-code prompt engineering tool. It is meant to help users build and evaluate prompts visually, although it still relies on your own API keys for model access.
How do support and account changes work?
The support page recommends checking the documentation and troubleshooting section first, then contacting support by email or Discord for other issues. It also says team account switches are handled by email, subscriptions can be canceled through the account menu, invoices are available in the Stripe billing portal, and refunds are not offered.