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verifiers: Build Environments for LLM Training and Evaluation

verifiers is a Python library for building environments that train and evaluate large language models. It connects those environments with Prime Intellect’s hub and training tools, making it useful for teams developing or running LLM reinforcement-learning workflows.

ActivePythonMITLibraryAIEvaluation
Stars
4.7k
Forks
696
Stars, last 16 days
+54
Last commit
today
Contributors
90

Our take

Activeregular commits and releases

Health score

73/100

How it is scored
Activity
85
Community
78
Issues
53
Pull requests
76

+54 stars in the last 16 days

  • Releases more often than 86% of the projects we track
  • Merges more pull requests than 80% of the projects we track
  • More contributors than 76% of the projects we track

verifiers is an actively maintained, MIT-licensed option for teams building LLM training or evaluation environments, with a sizable contributor base and regular releases.

Good fit if

  • You need a Python library for LLM training or evaluation environments.
  • Your workflow uses, or may benefit from, the Prime Intellect Hub, prime-rl, or hosted training integrations.
  • You can use Python 3.11 through 3.14 and want a project with recent commits and releases.

Look elsewhere if

  • You need a general-purpose evaluation tool unrelated to building LLM environments.
  • You require a non-Python implementation or support outside Python 3.11 through 3.14.
  • Your team does not want to depend on the Prime Intellect ecosystem and needs integrations the repository does not describe.
All health signals
Last commit2026-10-07 (today)
Commits, last 90 days100+
Releases, last 12 months46 (latest v0.3.1, 2026-08-24)
Contributors90 (top contributor: 39% of commits)
Issues closed, last 90 days2+
Project age21 months

Checked on 2026-10-07 with the GitHub API.

Overview

verifiers provides a library for creating environments to train and evaluate LLMs. It gives developers a way to define and work with the environments used in those workflows, rather than treating training and evaluation as separate tasks.

The project is designed to connect with Prime Intellect’s Environments Hub, the prime-rl training framework, and its hosted training platform. It is most relevant to teams building LLM reinforcement-learning environments or using those Prime Intellect services.

Key Features

  • Create environments for LLM training and evaluation.
  • Use the same library across training and evaluation workflows.
  • Integrate with the Prime Intellect Environments Hub.
  • Work alongside the prime-rl training framework.
  • Connect to Prime Intellect’s hosted training platform.
  • Consult human-written architecture guides in the repository’s docs/ directory.

Use Cases

  • An LLM researcher can build an environment for training a model with reinforcement learning.
  • An evaluation team can create environments to assess LLM behavior.
  • A developer publishing or discovering environments through Prime Intellect’s Environments Hub can use the library’s integrated workflow.
  • A team already using prime-rl or Prime Intellect Hosted Training can use verifiers to define its environments.

What you need

Detected in the repository

  • Python >=3.11,<3.15 (from pyproject.toml)
  • A test suite and automated checks on GitHub Actions

License in plain words

MITpermissive

  • Commercial use: yes
  • Modify and redistribute: yes
  • You must keep: the copyright and license notice
  • Share your changes: no

A summary, not legal advice: the LICENSE file is what applies.

Getting Started

Install the Prime CLI with uv:

uv tool install prime

See the README for setup details and the repository’s docs/ directory for architecture guides.

Alternatives

  • llmgym: LLMGym offers interactive environments for developing and evaluating LLM applications, while verifiers focuses on environments for LLM training and reinforcement learning.
ProjectLanguageLicenseStarsStatus
verifiersPythonMIT4.7kActive
llmgymPythonApache-2.041Archived

Considerations

The project is active, with frequent commits and releases, and has contributions from many developers rather than depending mainly on one. However, the measured issue data shows little recent closure activity, so teams should assess whether their open issues or support needs are being addressed. The repository specifies Python 3.11 to 3.14; it does not list Docker or Compose as requirements. The README does not specify hardware requirements, so check the needs of your intended training workload separately. The MIT license permits broad use, subject to its license terms.

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