A Python framework for building LLM-powered applications and agents, with standard interfaces for models, embeddings, vector stores and third-party integrations.
guardrails-ai/guardrails
A Python framework that adds input and output guards to LLM applications and generates validated structured data from LLM outputs.
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- 7,540
- Forks
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- Open issues
- 74
- Last commit
- 6 days ago
What is it?
Guardrails is a Python framework for making LLM-based applications more reliable. It runs input and output guards that detect, quantify and mitigate specific risks, built from validators that can be combined into a single guard. Validators are distributed through Guardrails Hub, and each can be installed as a separate package with pip.
The framework also helps generate structured data from LLMs. You define the expected output as a Pydantic model, and Guardrails produces output matching that schema, using function calling where the model supports it and schema-in-prompt instructions where it does not.
Guardrails can run as a standalone Flask service exposing a REST API, and it offers an OpenAI-compatible endpoint so existing OpenAI SDK clients can route calls through guards. The project is licensed under Apache-2.0.
Key features
- 01Input and output guards that check LLM inputs and responses against configurable validators.
- 02Pre-built validators from Guardrails Hub, such as regex matching, competitor checks and toxic language detection.
- 03Structured data generation from LLMs using Pydantic models.
- 04Function calling and prompt-based schema instructions for different model capabilities.
- 05Standalone server with a REST API and an OpenAI-compatible endpoint.
Use cases
- Filtering toxic or off-topic content in a chatbot before it reaches users.
- Preventing an assistant from naming competitors or leaking restricted information.
- Getting LLM responses in a fixed JSON structure for downstream code.
- Adding a validation layer to an existing OpenAI-based application without rewriting client code.
Quick start
- 1
Install the guardrails-ai package
pip install guardrails-ai - 2
Configure the Guardrails Hub CLI
guardrails configure - 3
Install a validator from Guardrails Hub
pip install guardrails-ai-regex-match - 4
Create a Guard with the installed validator and run it, as shown in the README
Things to know
- Guardrails is discontinuing its hosted remote inferencing, with a planned cutoff on August 25, 2026.
- Validators are moving to separate PyPI packages that must be installed individually.
Topics
FAQ
- What is guardrails?
- A Python framework that adds input and output guards to LLM applications and generates validated structured data from LLM outputs. Guardrails is a Python framework for making LLM-based applications more reliable. It runs input and output guards that detect, quantify and mitigate specific risks, built from validators that can be combined into a single guard. Validators are distributed through Guardrails Hub, and each can be installed as a separate package with pip.
- Is guardrails free to use? What license does it have?
- guardrails is open source under the Apache-2.0 license. Check the license terms before using it in commercial products.
- Is guardrails still maintained?
- Actively maintained. The last commit to guardrails was on Oct 15, 2026.
- What can I use guardrails for?
- Filtering toxic or off-topic content in a chatbot before it reaches users. Preventing an assistant from naming competitors or leaking restricted information. Getting LLM responses in a fixed JSON structure for downstream code. Adding a validation layer to an existing OpenAI-based application without rewriting client code.
- How do I install guardrails?
- Install the guardrails-ai package: pip install guardrails-ai Configure the Guardrails Hub CLI: guardrails configure Install a validator from Guardrails Hub: pip install guardrails-ai-regex-match Create a Guard with the installed validator and run it, as shown in the README
- Where can I get guardrails?
- The source code and installation instructions are on GitHub: https://github.com/guardrails-ai/guardrails
Summary generated by AI from the project's README. GitHub stats refresh daily.
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