Gymnasium: A Standard Interface for Reinforcement Learning Environments
Mark Towers, Ariel Kwiatkowski, Jordan Terry, John U. Balis, Gianluca De Cola, Tristan Deleu, Manuel Goul\~ao, Andreas Kallinteris, Markus Krimmel, Arjun KG, Rodrigo Perez-Vicente, Andrea Pierr\'e, Sander Schulhoff, Jun Jet Tai, Hannah Tan, Omar G. Younis

TL;DR
Gymnasium is an open-source library that standardizes the interface for reinforcement learning environments, facilitating easier development, comparison, and reproducibility of RL algorithms to accelerate research progress.
Contribution
It introduces a unified API and a collection of environments, tools, and abstractions to improve interoperability and reproducibility in RL research.
Findings
Streamlines RL algorithm development and testing
Enhances reproducibility and robustness of RL experiments
Provides a comprehensive suite of customizable environments
Abstract
Reinforcement Learning (RL) is a continuously growing field that has the potential to revolutionize many areas of artificial intelligence. However, despite its promise, RL research is often hindered by the lack of standardization in environment and algorithm implementations. This makes it difficult for researchers to compare and build upon each other's work, slowing down progress in the field. Gymnasium is an open-source library that provides a standard API for RL environments, aiming to tackle this issue. Gymnasium's main feature is a set of abstractions that allow for wide interoperability between environments and training algorithms, making it easier for researchers to develop and test RL algorithms. In addition, Gymnasium provides a collection of easy-to-use environments, tools for easily customizing environments, and tools to ensure the reproducibility and robustness of RL…
Peer Reviews
Decision·Submitted to ICLR 2025
Gym and now gymnasium is an essential part of reinforcement learning with many packages and works being built on top of or inspired by a similar methodology. The abstraction provided by the method is commonly used across reinforcement learning and is easy to use. The vectorization increases throughput of running an environment without significant overhead. The writing is fairly straightforward and it is easy to understand the methodology of the work. Without outside comparison, the results show
Despite the use of the name recognition of the library, it is unclear if the improvements from OpenAI Gym to Gymnasium are comparable to the contributions from other RL libraries 2015-present. My main issue with the work is the lack of discussion and comparison with similar work. (In section 2 the paper details a number of comparable works that can use their framework but this is not sufficient to my point.) The paper should complement technical report details with meaningful comparisons to help
- By providing a consistent API, Gymnasium streamlines RL research, making it easier for researchers to compare and build upon previous work. -The functional API enhances compatibility with theoretical frameworks like POMDPs and enables hardware-accelerated environments using libraries like JAX, which is beneficial for large-scale or computationally intensive applications. - The built-in vectorization features (Sync and Async) support efficient parallelization of environments, which can signific
The choice between Sync and Async vectorization modes shows substantial performance variability depending on hardware, which could lead to inconsistencies across different systems or add complexity for users lacking high-performance resources.
The paper provides a well-written, comprehensive overview of Gymnasium, which would be of use to a newcomer to this API. Gymnasium itself is an extremely valuable contribution to the RL community, as evidenced by its widespread adoption.
There is little original content in this paper as it is basically replicating the documentation available through the Gymnasium website (https://gymnasium.farama.org/index.html). The decision of whether to accept this paper or not really comes down to a philosophical question around the purpose of ICLR. The Reviewer's Instructions ask us to consider the paper's value from the contribution of the ICLR community ("What is the significance of the work? Does it contribute new knowledge and suffic
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Taxonomy
MethodsSparse Evolutionary Training · Focus · Lib
