The RT Topology Library exposes an API to create and manage standard (ISO 13249 aka SQL/MM) topologies using user-provided data stores.
The code found its origins within PostGIS, where in 2015 I implemented the first draft of the callback-based architecture with fundings from Regione Toscana (RT). The GIS department of the Italian Region government invested in PostGIS since 2010 and as of 2015 was interested in using the PostGIS Topology functionality also from Spatialite, which was already using the PostGIS liblwgeom library to implement other spatial functions.
Being in need of a more rapid test and release cycle, and with the aim to create a library compatible with both PostGIS and Spatialite, Tuscany Region decided to bootstrap this new library, derived from liblwgeom, and to add thread-safety to its offerings.
The RT Topology Library was funded in 2016 by "Regione Toscana - SITA" (CIG: 6445512CC1), which also funded many improvements in the originating liblwgeom.
RT-Topology development is managed by a committee formed by:
Official code repository is https://git.osgeo.org/gitea/rttopo/librttopo
Development mailing list is https://lists.osgeo.org/mailman/listinfo/librttopo-dev
Check out the code repository for development snapshots.