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Promptfoo

SecurityApplicationFree

Ensure LLM Security with Open-Source Vulnerability Testing.

Last updated Apr 28, 2026

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What is Promptfoo?

Promptfoo is an open-source tool designed to ensure the security and reliability of LLM (Large Language Models) applications. It offers a comprehensive vulnerability scanner specifically tailored to each LLM product, providing customized probes for detecting PII leaks, unauthorized prompt manipulations, and other critical failures. With capabilities like caching, concurrency, and detailed vulnerability reports, Promptfoo allows developers to build, test, and refine LLM applications efficiently with test-driven development rather than trial-and-error.

Promptfoo's Top Features

Key capabilities that make Promptfoo stand out.

Open-source

Customized vulnerability probes

Detection of PII leaks

Protection against unauthorized prompt manipulations

Prevention of jailbreaks

Detailed vulnerability reports

Support for multiple LLM API providers

Local operation without cloud dependencies

Test-driven LLM development

Community-supported

Use Cases

Who benefits most from this tool.

Developers of LLM applications

Ensuring security by detecting PII leaks, unauthorized prompt manipulations, and other vulnerabilities.

Security Analysts

Running comprehensive pentests to verify the security, privacy, and compliance performance of LLMs.

Open-Source Contributors

Collaborating on improving an open-source tool used for LLM security and reliability.

Large Organizations

Implementing reliable and secure LLM applications without depending on cloud services or SDKs.

Tech Startups

Rapidly developing and fine-tuning LLM models with customized tests and vulnerability scans.

Educators

Teaching students about LLM application security using a practical, open-source tool.

QA Engineers

Automating red teaming and security tests for CI/CD pipelines.

AI Researchers

Evaluating different LLM models and prompts efficiently using Promptfoo's comprehensive tools.

Compliance Officers

Ensuring LLM applications meet regulatory and compliance standards through detailed reporting.

Product Managers

Overseeing the development of secure LLM applications with actionable insights from vulnerability reports.

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Tags

open-sourcesecurityreliabilityLLMvulnerability scannerPII leaksprompt manipulationvulnerability reports

Promptfoo's Pricing

Free plan available

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Frequently Asked Questions

What is Promptfoo?
Promptfoo is an open-source tool for testing the security and reliability of LLM applications through customized vulnerability probes.
How does Promptfoo ensure the security of LLM applications?
Promptfoo uses customized vulnerability probes to detect issues like PII leaks, unauthorized prompt manipulations, and other critical failures.
Is Promptfoo open-source?
Yes, Promptfoo is completely open-source and supported by a community of seasoned contributors from major tech companies.
Can I use Promptfoo with different LLM API providers?
Yes, Promptfoo supports various LLM API providers such as OpenAI, Anthropic, Azure, Google, HuggingFace, and even allows for custom API integration.
What kind of vulnerabilities can Promptfoo detect?
Promptfoo can detect a range of vulnerabilities including PII leaks, competitor endorsements, unintended contracts, prompt injections, jailbreaks, and more.
Does Promptfoo require cloud dependencies or SDKs?
No, Promptfoo operates locally without the need for SDKs, cloud dependencies, or logins.
What is test-driven LLM development?
Test-driven LLM development involves building and refining LLM applications through systematic testing and evaluation, as opposed to trial-and-error methods.
How does Promptfoo help in building reliable LLM apps?
Promptfoo offers evaluations, security, and red teaming capabilities to build, test, and refine reliable LLM applications efficiently.
Can Promptfoo generate detailed vulnerability reports?
Yes, Promptfoo provides in-depth analysis of detected vulnerabilities along with practical remedies.
Who uses Promptfoo?
Promptfoo is trusted by over 20,000 developers, including teams from major tech companies for securing their LLM applications.