Project

Data Licensing & Attribution

What the data and code are licensed under, whose work this site is built on, and how to credit it downstream.

At a glance

Component License / terms Credit
Application code MIT License Chris Woodruff and contributors
Baseball statistics (1871–2025) CC BY-SA 3.0 Lahman Baseball Database (Sean Lahman; distributed by SABR)
Negro Leagues statistics See below Seamheads Negro Leagues Database (Gary Ashwill and researchers), via SABR

What the MIT license covers — and what it doesn't

The source code of this project — the web application, the REST API, the MCP server, and everything else in the GitHub repository — is released under the MIT License. You may use, modify, and redistribute the code freely with attribution.

The MIT license does not cover the data. The baseball statistics served by this site, its API, and its MCP server belong to their respective sources and carry their own terms, described below. Cloning the repository gives you the code, not the database; anything you build that redistributes the data must satisfy the data licenses, not just MIT.

The Lahman Baseball Database

The core statistics come from the Lahman Baseball Database, created and maintained by Sean Lahman and contributors since 1994 and now distributed by the Society for American Baseball Research (SABR). It is available under the Creative Commons Attribution-ShareAlike 3.0 Unported License: you may share and adapt the data, provided you credit the source and license any derivative data under the same terms.

[PENDING — do not publish until filled] Paste the substance of SABR's written redistribution confirmation here (from the #67 correspondence): what SABR confirmed about re-serving the data through this site, the public API, and the MCP server, and any conditions attached.

Negro Leagues data — the Seamheads Negro Leagues Database

The Negro Leagues statistics in the Lahman database are licensed from the Seamheads Negro Leagues Database, the reconstruction project led by Gary Ashwill with a team of researchers who have rebuilt these records box score by box score from digitized newspapers. This site would have nothing to show for these players without that work — and as our Surviving Records page explains, the reconstruction is still underway.

[PENDING — do not publish until filled] Paste the terms from the Seamheads / Gary Ashwill correspondence here (from #68): the permission or conditions granted for re-serving the Negro Leagues rows through the site, API, and MCP server, and the attribution wording they asked for.

If you build on this data

Data obtained through this site's API or MCP server inherits the source terms. At minimum:

  • Credit the Lahman Baseball Database (Sean Lahman / SABR) and license derivative data CC BY-SA 3.0.
  • Credit the Seamheads Negro Leagues Database for any use of Negro Leagues statistics.
  • Don't present the data as complete or context-adjusted — see the data scope statement.