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openai/evals

Analysis updated 2026-06-21

18,459PythonAudience · researcherComplexity · 3/5Setup · moderate

TLDR

A framework and benchmark library for testing how well AI language models perform, run existing tests or write your own to measure accuracy on tasks specific to your app.

Mindmap

mindmap
  root((openai evals))
    What it does
      Test AI model accuracy
      Benchmark registry
      Custom eval framework
    Eval types
      Model-graded evals
      YAML plus JSON evals
      Custom Python evals
    Use cases
      Compare model versions
      Private data testing
      App-specific benchmarks
    Audience
      AI researchers
      ML engineers
    Requirements
      OpenAI API key
      Python 3.9 plus
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What do people build with it?

USE CASE 1

Run an existing benchmark from the registry to compare two AI model versions on a set of standardized tasks

USE CASE 2

Write a custom eval using a YAML config and JSON test data to measure how well a model handles your app's specific use case

USE CASE 3

Build a model-graded eval where one AI judges whether another AI's answers are correct, without writing any code

USE CASE 4

Use private proprietary data to evaluate a language model without exposing that data publicly

What is it built with?

PythonYAMLGit LFS

How does it compare?

openai/evalsjantic/deoldifypython-world/python-mini-projects
Stars18,45918,46418,492
LanguagePythonPythonPython
Setup difficultymoderatemoderateeasy
Complexity3/53/51/5
Audienceresearchervibe codervibe coder

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · moderate Time to first run · 30min

Requires an OpenAI API key and a separate Git LFS fetch after cloning to access the benchmark datasets.

License information was not mentioned in the explanation.

In plain English

OpenAI Evals is a framework for evaluating large language models (LLMs), AI systems that generate text, and an open-source registry of benchmark tests for measuring their capabilities. An "eval" in this context is a structured test that runs a model against a set of inputs and measures how well its outputs match expected results. The project serves two purposes. First, it provides an existing library of benchmarks that test different capabilities of language models. Second, it gives developers a framework to write their own custom evaluations for use cases specific to their application, including private evals that use proprietary data without exposing it publicly. Custom evals can be built in two ways: model-graded evals, where another language model judges whether the output is correct (these are currently accepted as contributions), or evals with custom Python code (currently not accepted as community submissions). For basic evals, no coding is required, you provide data in JSON format and specify parameters in a YAML configuration file. To run evals, you need an OpenAI API key and Python 3.9 or later. The eval registry data is stored using Git LFS (Large File Storage), a Git extension for tracking large binary files, which needs to be fetched separately after cloning the repository. Results can optionally be logged to a Snowflake database. An interactive dashboard version is also available directly in the OpenAI platform without needing this codebase.

Copy-paste prompts

Prompt 1
Using the OpenAI Evals framework, show me how to create a simple custom eval that tests whether a model correctly answers multiple-choice questions from a JSON dataset
Prompt 2
How do I run an existing eval from the OpenAI Evals registry against gpt-4o and get a report of its accuracy?
Prompt 3
I want to build a model-graded eval where Claude judges whether GPT-4's answers to customer support questions are helpful. How do I configure this in the Evals YAML format?
Prompt 4
How do I fetch the Git LFS eval registry data after cloning the openai/evals repository so I can access the benchmark datasets?
Prompt 5
Show me how to log eval results to a Snowflake database when running the OpenAI Evals framework

Frequently asked questions

What is evals?

A framework and benchmark library for testing how well AI language models perform, run existing tests or write your own to measure accuracy on tasks specific to your app.

What language is evals written in?

Mainly Python. The stack also includes Python, YAML, Git LFS.

What license does evals use?

License information was not mentioned in the explanation.

How hard is evals to set up?

Setup difficulty is rated moderate, with roughly 30min to a first successful run.

Who is evals for?

Mainly researcher.

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