langtest vs promptfoo
Language-model testing and evaluation tools compared
langtest generates tests to assess NLP and language-model quality, including robustness, bias, fairness, and accuracy. promptfoo evaluates prompts and models, compares outputs, and red-teams LLM applications; it emphasizes developer workflows such as local runs and CI/CD.
langtest: Test Language Models for Safety and Quality
LangTest is a Python library for evaluating language models and NLP systems for robustness, bias, fairness, accuracy, and other quality risks. It supports NLP frameworks including Spark NLP and Hugging Face, plus several hosted LLM services.
promptfoo: Evaluate and Red-Team LLM Apps
Promptfoo is a TypeScript CLI and library for evaluating and red-teaming LLM-based apps. Compare prompts and models, scan for vulnerabilities, and run checks in CI/CD, with evaluations performed locally.
| langtest | promptfoo | |
|---|---|---|
| Language | Python | TypeScript |
| License | Apache-2.0 | MIT |
| Stars | 561 | 26.4k |
| Forks | 53 | 2.6k |
| Last analyzed | Oct 29, 2026 | Oct 24, 2026 |
Key differences
- langtest covers NLP tasks such as named entity recognition, translation, and text classification, alongside LLM checks; promptfoo focuses on prompts, models, and LLM-powered applications.
- langtest assesses quality concerns including bias, representation, fairness, and accuracy, and can augment training data for select models. promptfoo emphasizes output comparisons, red teaming, and vulnerability scanning.
- langtest is a Python library. promptfoo is a TypeScript CLI and library with a web viewer for evaluation results.
- langtest uses the Apache-2.0 license, while promptfoo uses the MIT license.
- promptfoo supports integrating evaluation and security checks into CI/CD and reviewing pull requests for LLM-related security and compliance issues. langtest supports integrations including Spark NLP, Hugging Face and Transformers, and supported LLM services.
- promptfoo has 25.7k stars and 2.4k forks, compared with langtest's 561 stars and 54 forks; both are unarchived.
Choose langtest if you…
- need to test NLP tasks such as named entity recognition, translation, or text classification.
- want to assess bias, representation, fairness, robustness, or accuracy with generated tests.
- want to use test results to guide training-data augmentation for select models.
Choose promptfoo if you…
- need to compare prompt revisions or model outputs across evaluation cases.
- want to red-team an LLM application or scan it for vulnerabilities.
- need to run evaluations or security checks locally or in CI/CD.
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This comparison is generated with AI from the OSRepos analyses of both projects. Always check each project's repository and documentation before choosing.