System Prompt Tester - Free Online Tool | PivaBox

Design test cases for system prompts — generate message variations, fill expected outputs, and export for API testing

How to Use System Prompt Tester

1. Enter your system prompt and conversation messages (User/Assistant) to define the test context
2. Set the temperature and max tokens settings, select a model for documentation, then click Generate Test Cases to create message variations (typos, rephrases, edge cases)
3. Fill in the Expected Output, Actual Output, and Notes columns in the results grid for each test case. Export as JSON to use with actual API testing tools

Frequently Asked Questions

Is System Prompt Tester free?

Yes, PivaBox System Prompt Tester is completely free. No API calls are made — it helps you design and organize test cases to run against actual AI APIs separately.

Does this tool call the AI models?

No. The model selector and settings are for documentation and test planning purposes only. This tool generates test case variations and provides a structured grid to record expected and actual outputs. You run the tests against real AI APIs yourself.

How do I use the exported JSON?

The exported JSON includes your system prompt, messages, settings, test cases, and results. You can write a script to iterate over the test cases and send them to OpenAI, Anthropic, or other AI APIs to automatically populate the actual output column.