Arquivo Histórico Municipal de São Paulo

The Arquivo Histórico Municipal de São Paulo officially launched its AtoM access platform during the September 2026 Festival Arquivo Aberto. At launch it held more than 24,000 item-level descriptions, presented within a hierarchy that lets researchers move between fonds, sections, series, files and individual items. Bringing the service into production involved migrating the existing database and customisations, resolving compatibility between software versions and services, rebuilding the search index, securing access and publishing the site. The resulting portal brings finding aids, spreadsheets, databases and archival descriptions together as a single research entry point. The source does not name the platform from which the database was migrated, so this is recorded as an AtoM implementation rather than a named system-to-system migration.