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Offline Prompt Tester

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Overview

Test any prompt with multiple LLM-powered perturbations using local backends

Offline Prompt Tester lets you stress-test your LLM prompts by generating variations — rephrased, simplified, formalized, or completely restructured — entirely on your own machine. No cloud. No API keys. No data leaves your device. Connect it to any locally-running LLM (Ollama, Jan.ai, LM Studio, or any OpenAI-compatible endpoint) and see how your prompts hold up when reworded. Free — no account needed • 4 perturbation types: Rephrase, Simplify, Formalize, Informalize • Compare up to 3 types side by side • Text similarity scoring (Levenshtein) • Word-level diff view (highlights exactly what changed) • Token count estimate per result • Pin your best results across sessions • Export results as .txt, .csv, or .pdf • Prompt library (save up to 5 prompts) • 7-day history • Right-click any text on any page → "Test this prompt" • Omnibox shortcut: type pt <your prompt> in the address bar • Auto-detects available models from your local server • 10 free tests per day Pro — one-time purchase, lifetime license • Unlimited tests per day • 9 additional perturbation types: Add/Remove Ambiguity, Change Perspective, Reverse Polarity, Add/Remove Constraints, Domain Shift, Role Injection, Adversarial AI similarity scoring and sentiment delta (via your local LLM) • Batch mode: run a perturbation across multiple saved prompts at once, with CSV export • Save up to 50 prompts • 30-day history

Details

  • Version
    1.1.0
  • Updated
    May 6, 2026
  • Features
    Offers in-app purchases
  • Offered by
    The Banished Prince
  • Size
    186KiB
  • Languages
    English (United States)
  • Developer
    Iniyavel S
    Varadharajapuram Sivohum, Plot 64, 65, 66, Fortune Residency, 1st Street Mudichur, Tamil Nadu 600048 IN
    Email
    archiehacker@protonmail.com
    Phone
    +91 73584 12963
  • Trader
    This developer has identified itself as a trader per the definition from the European Union and committed to only offer products or services that comply with EU laws.

Privacy

Manage extensions and learn how they're being used in your organization
The developer has disclosed that it will not collect or use your data. To learn more, see the developer’s privacy policy.

This developer declares that your data is

  • Not being sold to third parties, outside of the approved use cases
  • Not being used or transferred for purposes that are unrelated to the item's core functionality
  • Not being used or transferred to determine creditworthiness or for lending purposes

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