Fuzz Test AI Prompts with
Variable Mutations
Input prompt templates with {{variables}}, auto-generate hundreds of edge case variations, test against OpenAI & Anthropic APIs, and surface failure cases before they hit production.
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Mutation Engine
Generates empty strings, special chars, long text, Unicode, injections, and more for every variable.
LLM API Testing
Runs variations against OpenAI and Anthropic in parallel. Captures errors, timeouts, and unexpected outputs.
Failure Dashboard
Highlights failing cases with diffs, response previews, and exportable reports for your team.
Simple Pricing
Pro
$39/mo
Everything you need to ship reliable prompts
- ✓ Unlimited prompt templates
- ✓ 500+ mutation strategies per variable
- ✓ OpenAI & Anthropic API support
- ✓ Failure reports & CSV export
- ✓ Team sharing & history
FAQ
What LLM APIs are supported?
Currently OpenAI (GPT-4o, GPT-4, GPT-3.5) and Anthropic (Claude 3.5, Claude 3). More providers coming soon.
Do I need to provide my own API keys?
Yes. You bring your own OpenAI or Anthropic API keys. We never store them — they are used only during your active session.
What kinds of mutations does the engine generate?
Empty strings, whitespace-only, very long text, SQL/HTML/prompt injection attempts, Unicode edge cases, null-like values, and custom user-defined mutations.