Memory Foyer

Context

A spaced-repetition trainer with a small 3D foyer for picking a deck. The flashcard domain is deliberately plain — it is a vehicle for the two things a closed-source portfolio cannot show.

The hard part

Every commercial project I shipped lives in a private repository, so none of my code is readable by anyone deciding whether to hire me. A Unity-only portfolio also says nothing about the server side.

Split the project into five assembly-enforced layers. Domain and Application compile with no engine reference at all, so the scheduling algorithm and session orchestration build and unit-test as plain C#; time enters through an IClock interface.

Made the server authoritative: the SM-2 algorithm exists twice, once as pure C# and once as server JavaScript, each with its own test suite, and the server result overwrites the client cache after every submission.

Made submission idempotent — de-duplicated on session id plus a payload hash, with request validation on every endpoint.

Wrote an offline path that degrades instead of failing: HTTP is primary, an atomic JSON cache is the fallback, and queued sessions drain in order once the connection returns.

Built a Deck Author window in UI Toolkit so deck content stays one diffable file instead of scattered assets.

Covered every layer with tests: twelve edit-mode suites on the client, plus algorithm and HTTP integration suites on the server.

A project that can be read, run and tested by a stranger — and a written list of its own limits, from last-write-wins across devices to the write-ahead log that a production version would need.

Worth calling out

I built this one end to end. These are the parts worth naming.

The architecture

• Five layers with dependencies pointing inward, enforced by assembly definitions rather than by convention.
• Domain and Application kept free of UnityEngine so the core is testable without the editor.
• Dependency injection, async and in-process messaging wired through VContainer, UniTask and MessagePipe.

The server

• Five endpoints on Express and SQLite with schema-validated requests.
• Idempotent submission keyed on session id and payload hash.
• The scheduling algorithm reimplemented server-side as the source of truth.

The honest part

• A trade-offs section that names what the project does not do and why, instead of hiding it.

More from the project

Project facts

Year

2026

Role

Solo developer

Scope

Client, server, tooling and tests

Engine

Unity 6000.4.1f1, URP

Backend

Node, Express, SQLite

License

MIT

Built

29 April to 20 May 2026 — about three weeks

Scheduling

A published spaced-repetition algorithm, reimplemented server-side as the source of truth

Status

Finished as a personal project — not a commercial-grade product

Source

github.com/devID767 ↗

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