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About Stan

Stan is a state-of-the-art platform for statistical modeling and high-performance statistical computation. Thousands of users rely on Stan for statistical modeling, data analysis, and prediction in the social, biological, and physical sciences, engineering, and business.

Users specify log density functions in Stan's probabilistic programming language and get:

  • full Bayesian statistical inference with MCMC sampling (NUTS, HMC)

  • approximate Bayesian inference with variational inference (ADVI, Pathfinder)

  • penalized maximum likelihood estimation with optimization (L-BFGS)

Stan's math library provides differentiable probability functions & linear algebra (C++ autodiff). Additional R packages provide easy formula syntax to specify linear and generalized linear hierarchical models, posterior visualization, and leave-one-out cross-validation.

Get Started

Stan interfaces with the most popular data analysis languages (R, Python, shell, MATLAB, Julia, Stata) and runs on all major platforms (Linux, Mac, Windows). To get started using Stan begin with the Installation and Documentation pages.

Helping Out

Stan is an active and open developer community. The help-wanted and good-first-issue labels in our repositories try to highlight good places to get started, and we're happy to help more on our forums or Slack.

We have projects in C++, Python, R, OCaml, and more. If you want to help build future versions of Stan, we want to help you get started.

Citing Stan

We appreciate citations for the Stan software because it lets us find out what people have been doing with Stan and motivate further grant funding. See How to Cite Stan for more details.

Open Code & Reproducible Science

Stan is freedom-respecting, open-source software (new BSD core, some interfaces GPLv3). Stan is associated with NumFOCUS, a 501(c)(3) nonprofit supporting open code and reproducible science, through which you can help support Stan.

Popular repositories Loading

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Repositories

Showing 10 of 52 repositories
  • cmdstanpy Public

    CmdStanPy is a lightweight interface to Stan for Python users which provides the necessary objects and functions to compile a Stan program and fit the model to data using CmdStan.

    stan-dev/cmdstanpy’s past year of commit activity
    Python 182 BSD-3-Clause 78 26 (1 issue needs help) 2 Updated Nov 8, 2025
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    stan-dev/stanc3’s past year of commit activity
    OCaml 146 BSD-3-Clause 48 84 (12 issues need help) 8 Updated Nov 7, 2025
  • pkgdown-config Public

    pkgdown template for Stan R package websites

    stan-dev/pkgdown-config’s past year of commit activity
    HTML 0 0 1 0 Updated Nov 5, 2025
  • math Public

    The Stan Math Library is a C++ template library for automatic differentiation of any order using forward, reverse, and mixed modes. It includes a range of built-in functions for probabilistic modeling, linear algebra, and equation solving.

    stan-dev/math’s past year of commit activity
    C++ 797 BSD-3-Clause 198 303 (40 issues need help) 17 Updated Nov 4, 2025
  • cmdstanr Public

    CmdStanR: the R interface to CmdStan

    stan-dev/cmdstanr’s past year of commit activity
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  • rstan Public

    RStan, the R interface to Stan

    stan-dev/rstan’s past year of commit activity
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    stan-dev/loo’s past year of commit activity
    R 154 36 42 (1 issue needs help) 8 Updated Oct 30, 2025
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    bayesplot R package for plotting Bayesian models

    stan-dev/bayesplot’s past year of commit activity
    R 436 GPL-3.0 86 57 (6 issues need help) 9 Updated Oct 29, 2025
  • posterior Public

    The posterior R package

    stan-dev/posterior’s past year of commit activity
    R 168 23 60 (1 issue needs help) 8 Updated Oct 29, 2025