Freedom251 › Statistical Analysis Software
Phitter
What Phitter is
Phitter fits observed data to theoretical probability distributions and ranks candidate models. Its web application covers 87 distributions, including 77 continuous and 10 discrete distributions. It reports Kolmogorov–Smirnov and chi-square results for discrete fits, plus Anderson–Darling results for continuous fits. Results include fitted density or mass, cumulative distribution, and Q–Q plots. Users can paste observations or import TXT, CSV, XLSX, or data from a public URL; the web app requires at least 20 numeric observations. Fitting runs locally in the browser through Pyodide and WebAssembly, so observations are not sent to a Phitter fitting server. A Python package is also available for notebooks and pipelines, and its kernel is open source under the MIT licence. Phitter has a free plan at no cost, with no account and no row limit. The project describes uses in data science, operations research, and artificial intelligence. Its creator is Sebastián José Herrera Monterrosa.
Who it suits
Phitter suits people who need to compare probability distributions against observed data, including users in data science, operations research, or artificial intelligence. It offers both a browser workflow and a Python package for notebooks and pipelines.
What it does well
- Covers 87 continuous and discrete distributions.
- Reports multiple goodness-of-fit results.
- Supports TXT, CSV, XLSX, and public URLs.
- Fitting runs locally in the browser.
- Free plan requires no account and has no row limit.
What to know first
- Web application requires at least 20 numeric observations.
- Site uses analytics and external services.
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Free | No account · no row limit | Free |
As phitter.io lists them, read 9 Oct 2026. The maker's own page has the final word.
Verdict
Phitter is focused on distribution fitting, with visual results and several goodness-of-fit measures. Its local browser calculation and Python package offer two ways to work with data, within the stated input and method scope.
Facts from Phitter's own pages
- Bayesian analysis
- No · phitter.io, 23 Sept 2026
- Browser processing
- The fitting calculation runs locally through Pyodide and WebAssembly, and observations are not sent to a Phitter fitting server. · phitter.io, 9 Oct 2026
- Creator
- The project says it was created by Sebastián José Herrera Monterrosa. · phitter.io, 9 Oct 2026
- Data import formats
- TXT, CSV, XLSX, public URL · phitter.io, 23 Sept 2026
- Data input
- Users can paste observations or import TXT, CSV, XLSX, or a file served from a public URL. · phitter.io, 9 Oct 2026
- Deployment
- both · phitter.io, 23 Sept 2026
- Distribution catalogue
- The web application covers 87 distributions: 77 continuous and 10 discrete. · phitter.io, 9 Oct 2026
- Free plan
- Yes · phitter.io, 23 Sept 2026
- Goodness-of-fit
- It reports Kolmogorov–Smirnov and chi-square results for discrete fits, and also Anderson–Darling results for continuous fits. · phitter.io, 9 Oct 2026
- Intended users
- The project describes applications in data science, operations research, and artificial intelligence. · phitter.io, 9 Oct 2026
- Minimum sample
- The web application requires at least 20 numeric observations. · phitter.io, 9 Oct 2026
- Open source
- The Python kernel is open source under the MIT licence. · phitter.io, 9 Oct 2026
- Privacy detail
- The site says it uses analytics and external services described in its privacy policy. · phitter.io, 9 Oct 2026
- Purpose
- Phitter fits observed data to theoretical probability distributions and ranks candidate models. · phitter.io, 9 Oct 2026
- Python library
- Phitter is also available as a Python package for notebooks and pipelines. · phitter.io, 9 Oct 2026
- Regression models
- No · phitter.io, 23 Sept 2026
- Research record
- Phitter has a peer-reviewed software paper in the Journal of Open Source Software. · phitter.io, 9 Oct 2026
- Scripting support
- Yes · phitter.io, 23 Sept 2026
- Statistical tests
- Yes · phitter.io, 23 Sept 2026
- Visualizations
- Results include fitted density or mass, cumulative distribution and Q–Q plots. · phitter.io, 9 Oct 2026
Where Phitter stands on Freedom251
- Statistical Analysis Software#47 of 106