PromptBuilder: Visual Prompt Engineering#

Overview#

PromptBuilder is an open-source tool for designing and testing prompts visually. It provides a split-pane interface with real-time previews, version control, and A/B testing capabilities.

Key Features#

Visual Editor#

Syntax-highlighted prompt editing
Variable interpolation with {{placeholders}}
Template library with common patterns
Side-by-side input/output preview

Version Control#

Git-like versioning for prompts
Diff view between prompt versions
Branch and merge prompt variants
Rollback to any previous version

A/B Testing#

Compare prompt variants side by side:

Run multiple prompts against the same input
Score outputs with custom rubrics
Statistical analysis of performance
Export results as CSV/JSON

Architecture#

The tool is built with a simple but effective stack:

Frontend: React + Monaco Editor
Backend: Node.js with WebSocket for real-time updates
Storage: SQLite for prompt history

Quick Start#

bash

git clone https://github.com/example/prompt-builder
cd prompt-builder
npm install
npm run dev

Open http://localhost:3000 and start building prompts.