Discussion on Solid specs and impact on implementations

by Maria Dimou (CERN), Michiel de Jong, Ruben Verborgh (Gent University), Sarven Capadisli (Inrupt), Tim Berners-Lee




This is a follow-up of the January 2022 Solid World.

Discussion points

  1. Clarify specification changes. @sarven
  2. How policy changes impact the specifications.
  3. Impact on the implementations (NSS and CSS in particular).
  4. Impact on the pod migrator. Aukje (developer PDS Interop team) and Sjoert (muze)
  5. Impact on the test suite. @michiel
  6. The work being done by interoperability panel related to "how the implementations will be stable, secure and the applications will multiply with enviable usability." @justin
  7. What about security and encryption in the implementations - plans, commitments. @joachim
  8. What about usability. The UI is the biggest handicap for Solid to be universally adopted. @ruben @timea


Sir Tim Berners-Lee (Solid project leader), Michiel de Jong (test-suite expert), Ruben Verborgh (CSS project leader), Sarven Capadisli (Solid Technical Reports' Editor), Maria Dimou (CERN-Solid collaboration manager), Auke van Slooten (, Sjoerd van Groning (muze), Sharon Stratsianis (SolidOS developer), Theo Meyer (MSc student, CSS evaluator), Lukas Vanhoucke (CERN), Jan Schill (CERN-Solid PoC developer), Jack Henschel (CERN), Timea Turdean (Inrupt - Solid World manager).

Executive Summary

The Solid specification being now on version 0.9.0, meaning close to final, further changes can only be few, well justified and agreed.
The top-of-the-list Solid server implementations NSS, ESS, CSS show deviations from the specs on few specific points (see table).
These deviations were well thought of and done by justifiable design choices and to serve existing use cases.
Adherence to the specs is not a dogmatic issue but a technical one.
The test-suite, users' pods  migration, ACLs re-adjustment, Solid applications' development are affected by the differences amongst Solid server implementations and get discouraged in the process of getting familiar with the Solid technical solutions and embrace the Solid project ideology. This is why the necessary changes to the specs should continue to be discussed between editors and implementors now that we are at an important point for Solid.
This was agreed by all participants and started immediately by with this example issue discussed at the meeting . Mutual thought and talk shall continue with ad-hoc technical meetings between all interested parties, i.e. the Solid project leadership, specs' editors, implementors, apps' developers, "customers". Posting comments in github issues is sometimes not enough to fully understand the various positions.
Next technical event is on CSS.

Item 6 was requested by Justin, he didn't join, so it wasn't discussed. Items 7,8 were not discussed due to lack of time. They shall be discussed next week  in the CSS and the Women-of-Solid meetings.

Please join our channel and contact Maria Dimou for further information on the CERN-Solid collaboration.

Organized by

Maria Dimou