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Credits and sources

LocalMass exists because many people give their time freely. Parishioners confirm times after Mass, parish staff keep their listings current, and volunteers around the world map churches and build open software. We thank every one of them. This page names the people and sources that we draw on, and the license of each.

The people

Parishioners and visitors confirm schedules, describe how Mass is celebrated, and report changes. Parish staff claim their church and keep its times correct. Reviewers and moderators check each edit before it goes live. OpenStreetMap mappers put most of these churches on the map in the first place.

LocalMass contributors

The first names will appear here soon.

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Data

OpenStreetMap
The locations, names, and addresses of Catholic churches, and some Mass times, imported from the map that volunteers build.© OpenStreetMap contributors · Open Database License (ODbL) 1.0
Nominatim
Address search when a place is not in our own city and ZIP code index.Data © OpenStreetMap contributors · ODbL 1.0
U.S. Census Bureau
City and ZIP code locations from the 2024 Gazetteer Files, and city populations from the Vintage 2024 population estimates.Public domain (U.S. government work)
timezone-boundary-builder
The time zone of each church, so that times show correctly, through the tz-lookup library by The Dark Sky Company.Evan Siroky; built from OpenStreetMap data · ODbL 1.0 (data), CC0 (tz-lookup)
United States Conference of Catholic Bishops
The norms for holy days of obligation in the United States, including when the obligation is lifted.Calculated by LocalMass from the published norms

Church data from OpenStreetMap that LocalMass users have corrected or extended stays available under the same Open Database License. Mass times are never invented: each time comes from one of the sources above or from a person who attends.

Maps

OpenFreeMap
The free map tiles and map styles behind every map on the site.Free to use, no API key
OpenMapTiles
The vector tile schema and styles that OpenFreeMap serves.BSD 3-Clause (code), CC-BY 4.0 (styles)
MapLibre GL JS
Draws the interactive map in your browser.BSD 3-Clause

Typefaces

Cormorant Garamond
Headings and the italic “Local” in the logo.Christian Thalmann · SIL Open Font License 1.1
Cinzel
The Roman capitals “MASS” in the logo, after the Trajan inscription.Natanael Gama · SIL Open Font License 1.1
Inter
Body text and interface labels.Rasmus Andersson · SIL Open Font License 1.1
Fontsource
Packages the fonts so that LocalMass can host them itself.MIT

Software

React
User interface library.MIT
Next.js
The application framework and its App Router.MIT
vinext
Runs the Next.js app on Vite and Cloudflare Workers.MIT
Vite
Build tool.MIT
Tailwind CSS
Styles.MIT
Lucide
Icons.ISC
Cloudflare Workers, D1 and Turnstile
Hosting, the database, and spam protection.Hosted service

Corrections

If we have left out a source or credited one wrongly, please use “Report a problem” on any church page, or see About LocalMass. LocalMass is an independent lay project and is not an official site of the Holy See, the USCCB, any diocese, or any parish.