Promptmetheus is a prompt engineering workspace for developers and teams. Compose instructions from blocks, supply test data and compare model outputs as you revise prompts for AI applications and automations. Its cloud editor keeps project history and supports collaboration, while a separate free playground offers a simpler place to start.
Checked against the site's own pages on .
Our take
We'd consider the editor when prompt changes need a repeatable review process across a project. Occasional AI chatting probably doesn't justify this setup. The subscription buys the workspace, so budget for model-provider usage separately and check that your preferred provider fits the workflow. Start with the trial before moving a team's prompt library into it.
Features
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Prompts built from blocks
Compose the user message from sections, then send it to a selected model; the getting-started guide walks through creating and renaming that first prompt.
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Model output comparison
The model catalog and completion ratings help compare a prompt's output across supported models, while cost estimates make the model choice part of the editing process.
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Automatic completion evaluators
Custom evaluators check generated responses against requirements, with datasets supplying changing context so a prompt can be examined beyond a single hand-written example.
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Versioned project work
Projects group prompts and their outputs, and the editor records changes so collaborators can trace which prompt version produced a result.
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Your own provider keys
The documentation says keys stay in the browser and are passed to the selected provider, so using a different browser or device requires entering them again.
Pricing
- Model
- Freemium
- Free tier
- Forge is a free playground with local storage and OpenAI models; the cloud Prompt IDE is a separate product.
- Paid plans
- Single costs $29 per month with a 7-day trial. Team is $99 per month for 3 users, plus $19 per month for each additional user.
Best for
- Developers maintaining prompts used by an application
- Teams comparing prompt versions against test data
- Automation builders evaluating model outputs
- Collaborators who need a shared prompt workspace
Not for
- People seeking a finished AI writing assistant
- Buyers expecting the editor subscription to include model inference credits
Limits
- Model inference is billed separately and needs your own provider API keys.
- The main website specifies a screen of 12 inches or larger for the editor.
FAQ
- Is Promptmetheus prompt engineering free?
- Forge is the free option. It stores work locally and supports OpenAI models, while the paid Prompt IDE adds cloud sync and a wider provider choice.
- Can I move existing work from Forge into Archery?
- Export a Forge backup, then use Archery's Import project option. Support notes that earlier playground history cannot be recovered and that the reverse migration, from Archery to Forge, isn't supported.
- Can a prompt or dataset move between projects?
- The getting-started FAQ says this isn't currently available, which matters if you expect to reorganize a library across existing projects.
Sources
- promptmetheus.com/ (opens in a new tab) Editor features, model catalog and advertised plan prices
- docs.promptmetheus.com/ (opens in a new tab) First-prompt workflow, signup and project restrictions
- docs.promptmetheus.com/subscriptions (opens in a new tab) Trial expiration and subscription management
- docs.promptmetheus.com/api-keys (opens in a new tab) Inference charges and provider-key handling
- promptmetheus.com/support (opens in a new tab) Forge migration and its history limitations
- docs.promptmetheus.com/models (opens in a new tab) Model selection, configuration and cost estimates