PromptForge

PromptForge is an agentic prompt refinement platform with a Next.js frontend and a FastAPI + LangGraph backend. It runs a creator/critic loop against OpenRouter models, stores runs in Postgres, and presents a modern studio UI for refining prompts.

What’s Inside

• Frontend: Next.js app (Tailwind + Base UI)
• Backend: FastAPI + LangGraph + SQLAlchemy (async)
• LLM: OpenRouter via langchain-openai
• DB: PostgreSQL (asyncpg)

PromptForge/
├── frontend/
└── backend/

Quick Start (Local)

1) Backend

Prereqs: Python 3.13+, Postgres, OpenRouter API key

cd backend
uv sync

Create .env in backend/:

DATABASE_URL=postgresql+asyncpg://user:pass@host:5432/dbname
OPENROUTER_API_KEY=your_openrouter_key
ENV=development
DEBUG=True

Run the API:

uv run uvicorn app.main:app --reload --port 8000

Notes:

• On startup (in development), the backend will auto-create tables.
• If you run the backend from the repo root, it still finds backend/.env.

2) Frontend

Prereqs: Node 18+ (or Bun/PNPM)

cd frontend
npm install

Create frontend/.env.local:

NEXT_PUBLIC_API_BASE=http://localhost:8000

Run the UI:

npm run dev

Open: http://localhost:3000

Environment Variables

Backend (backend/.env)

Variable	Required	Description
DATABASE_URL	Yes	Postgres async URL (postgresql+asyncpg://...)
OPENROUTER_API_KEY	Yes	OpenRouter API key
ENV	No	development or production
DEBUG	No	True/False

Frontend (frontend/.env.local)

Variable	Required	Description
NEXT_PUBLIC_API_BASE	Yes	Backend URL (e.g., http://localhost:8000)

Model Support

The frontend sends creator_model and critic_model directly to the backend. The backend forwards them to OpenRouter without validation.

If a model ID isn’t supported by OpenRouter, the request will fail. Consider adding a backend /models endpoint or a validation list if you want guardrails.

Troubleshooting

• DB errors: confirm DATABASE_URL uses the postgresql+asyncpg:// scheme.
• CORS: backend allows all origins in development by default.
• Model errors: ensure the model name exists on OpenRouter.

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If you want a single-command dev runner (frontend + backend), I can add one.