Case study
Atrium
A platform for the operative day of a school
The school day, on paper
A school runs on a hundred small records a day.
Who is present, who is sick, which teacher is out, which class has cleaning duty, which letter went home to which parents. At most schools these records live in separate tools, in spreadsheets, or on paper, and the school office retypes them from one place into the next.
Atrium gathers this operative day in one place: class register, reliability list, absences and sick notes, teacher absences, parent letters, cleaning rota, grade records. It is built for the people who carry that day, which means the office, the teachers, and the parents.
The judgment calls
Most of the architecture is restraint.
Official data keeps its home
Certificates, grades, and promotions stay in the school's official system of record, Atlantis at the pilot school. Atrium syncs from it and never has the last word.
Students are records, not users
Student data is synced from the official system. Students get no accounts and no app access, by design.
No passwords
Atrium is an OIDC relying party only. Identity and roles come from the school's identity provider, and Atrium stores no credentials.
One school, one instance
Every school runs its own isolated instance, deployed and owned by that school's infrastructure repository.
One contract, every surface
A single typed API schema is the source of truth.
The API contract is written once, as an Effect HttpApi schema. The backend implements it, the web client consumes it typed, and the OpenAPI documentation is generated from it. When the contract changes, every consumer fails to compile until it follows.
Behind the contract sits a modular monolith on Bun. The web app is built with TanStack Start, and a mobile app follows once the pilot has settled the API. Deployment is declarative: the first production instance is owned by the pilot school’s own infrastructure repository.
Where it stands
In pilot at its first school.
The Freie Evangelische Schule Kirchheim runs the first Atrium pilot. The path there is its own story: a website engagement that grew into infrastructure and then into a product. It is told in the FESK case study.
A public home for the product is coming at atrium.schule this autumn.