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AI Prompt Tester & Comparator

Compare two to four prompt variants side by side with word-level diffs, token estimates and the {{variables}} each one uses.

AI Prompt Tester & Comparator

3 variations
18 words / 134 chars~34 tokens
{{query}}
18 words / 125 chars~32 tokens
{{query}}
20 words / 152 chars~38 tokens
{{domain}}{{query}}
Test and compare prompt variations side-by-side. No API calls — purely client-side analysis.

What this tool does

The AI Prompt Tester and Comparator puts prompt variations side by side so you can see which one wins before deployment. It counts tokens for each version, highlights the exact diffs between them, and tracks variables across variants, running entirely in your browser so no prompt text leaves your machine.

Updated . Provided as is. Check the output before you rely on it in production.

How to use AI Prompt Tester & Comparator

  1. 1

    Write prompt variations

    Create two or more versions of the same prompt with different wording, structure or instructions, or load the sample.

  2. 2

    Compare the wording

    Switch between side-by-side and diff view to see exactly what changed between any two variations.

  3. 3

    Check size and variables

    Compare characters, words, estimated tokens and template variables for each variation.

  4. 4

    Test them in your model

    The tool does not call any model. Run each variation against the same input in your provider's playground or eval harness and record the outputs.

  5. 5

    Iterate on the winner

    Refine the best-performing variation and compare it against new alternatives.

Questions and answers

What is AI Prompt Tester & Comparator?
Prompt comparison means checking how two wordings of an instruction differ in content, length and variables before you test them on a model. This tool holds two to four variants, diffs any pair word by word, estimates tokens at about four characters each, and lists the {{variables}} each uses.
Does AI Prompt Tester & Comparator store or send my data?
No. All processing happens entirely in your browser. Your prompts stay on your device — nothing is sent to any server.
Can AI Prompt Tester & Comparator actually run prompts against AI models?
No. This tool is for offline prompt analysis — comparing structure, token counts, and differences between variations. It does not make API calls to any AI model. Use it to optimize prompts before testing them live.
For AI agents: how to call this tool

Machine-readable contract, endpoints and examples. Humans can ignore this section.

Best Path For Builders

Browser workflow

Runs instantly in the browser with private local processing and copy/export-ready output.

Browser Workflow

This tool is optimized for instant in-browser execution with local data handling. Run it here and copy/export the output directly.

/ai-prompt-comparator/

For automation planning, fetch the canonical contract at /api/tool/ai-prompt-comparator.json.