A hobby built on shared knowledge.
What it is
Open Stamp Commons (OSC) is a free, open, community-built philatelic resource. It provides a CC0-licensed catalog of stamps, the Open Stamp ID (OSID) system, and the platform that makes both usable.
OSC is not trying to replace existing reference works. It adds something different: a free, machine-readable foundation that any of those resources can build on. The same way OpenStreetMap exists alongside Google Maps and printed atlases.
Why now
Collecting has gone online and global. Software is now part of the hobby — inventory apps, identification tools, mobile cameras for instant lookup. And the next generation discovers stamps in search results, not in libraries.
Open identifiers and machine-readable data are the foundation that other knowledge communities — MusicBrainz, OpenStreetMap, GBIF, ORCID — built decades ago. Philately has not yet had its equivalent.
The idea
A few ideas shape the project. The catalog is free to browse and search, and no account is needed to look a stamp up. The records are published under an open CC0 license, so the data is shared, not locked away.
It is curated and governed by the people who use it, rather than a company that owns it. Records carry stable identifiers and structured fields, which makes them easy to cite and to build on. Programmatic access is through the API, with higher-volume tiers for developers and institutions who need them. And records are reviewed in the open, with their history visible.
Where this is headed
The work starts with the United States and grows outward as the community does. First, we publish the founding specifications, seed a few hundred verified US records, and open contribution to anyone who wants to help.
From there: comprehensive US coverage — postage, revenue, and stationery — and the first appointed Stewards, drawn from contributors who have earned trust. Then Commonwealth issues — Great Britain, Canada, Australia, New Zealand — as an international community forms, and in time, global coverage, as fast as careful verification allows.