Simple-Evals

Evaluation tools for language models by OpenAI.

GrowingOpen SourceLow lock-in

Pricing

Free tier

Flat rate

Adoption

Stable

License

Open Source

Data freshness

Aging · Jun 8, 2026

Overview

What is Simple-Evals?

Simple-Evals provides a set of evaluation tools and utilities to assess the performance of language models. It is designed to help developers understand how well their models are performing under various conditions, ensuring reliable and accurate outputs.

Key differentiator

Simple-Evals stands out by offering a comprehensive and flexible framework for evaluating language models, making it easier to integrate into existing development workflows without the need for extensive setup.

Capability profile

Capability Radar

Ease of StartEcosystemValueMaturityFlexibilityScale Ready

Honest assessment

Strengths & Weaknesses

↑ Strengths

Comprehensive evaluation metrics for language models.medium

Easy integration with existing model pipelines.medium

Supports various types of evaluations including accuracy, consistency, and robustness.medium

↓ Weaknesses

Steep learning curve for non-Python developershigh

API requires Python-specific patterns, TypeScript SDK is community-maintained

Frequent breaking changes between versionsmedium

v0.1 to v0.2 migration required rewriting chain definitions

Limited documentation for advanced use caseshigh

Detailed guides and examples are lacking, making it hard to implement complex evaluations

Performance issues with large datasetsmedium

Evaluation processes can become slow when dealing with very large datasets or models

Fit analysis

Who is it for?

✓ Best for

Developers who need to evaluate the robustness and accuracy of their custom-trained language models.

Teams working on natural language processing projects requiring rigorous testing frameworks.

Researchers comparing different language models for specific tasks.

✕ Not a fit for

Projects that require real-time evaluation capabilities as Simple-Evals is designed for batch processing.

Use cases where a graphical user interface (GUI) is preferred over command-line or script-based evaluations.

Cost structure

Pricing

Free Tier

Available

Open source — free to use

Starts at

$0

Model

Flat rate

Enterprise

None

Performance benchmarks

How Fast Is It?

Ecosystem

Relationships

Next step

Get Started with Simple-Evals

Step-by-step setup guide with code examples and common gotchas.

View Setup Guide →