Documentation

Right now, the documentation is the project.

It is the source of truth for the design and travels with every change in the same unit of work. A document that contradicts the implementation is a defect, not a stale file.

Start at the map The repository

Conventions

Language. English for documentation, decisions and every identifier in code, API, database and protocols. The interface ships German and English, with English as the fallback.
Diagrams. Mermaid, inline in the Markdown. No separate tool, no binary artifacts.
Identifiers. Requirements and decisions carry stable numbers that are never reused. A dropped requirement is marked withdrawn, not deleted.
Cross-references. Documents point at each other rather than repeating. What is written twice drifts.

Architecture

arc42-oriented, fourteen chapters

01 Introduction and goalsWhat the system is, and why it exists 02 Constraints and contextWhat is settled, and what is deliberately still open 03 Solution strategyThe broad strokes, before the detail 04 Building blocksWhat the system consists of 05 Runtime viewHow it behaves while it runs 06 Deployment viewWhere it runs, and the version matrix 07 Data modelTables, attributes, the change log 08 API contractREST, GraphQL, errors, versioning 09 Extensibility and pluginsPorts, manifests, capabilities, isolation 10 Identification and labelsCodes, scanning, label media, printing 11 Offline synchronisationPush, pull, the three-way compare 12 SecurityThe whole concept, not a checklist 13 Operations and observabilityBackup, restore verification, metrics, runbooks 14 Quality, risks, glossaryQuality goals, named risks, the vocabulary

Decisions

All 44 records

Every load-bearing choice has its own record with the rationale and the alternatives that were rejected. Ten that explain most of the rest:

ADR-0002A modular monolith with a plugin system, not microservices ADR-0004Attributes in JSONB plus an application-maintained index table ADR-0014Full bidirectional offline synchronisation ADR-0016UUIDv7 internally, a separate public code for print ADR-0018AGPL-3.0-or-later for the core, Apache-2.0 for the plugin API ADR-0022Rootless is mandatory; rootful is unsupported ADR-0024The malware scan is mandatory and fail-closed ADR-0026Every outbound connection leaves the core and becomes a plugin ADR-0030Ten characters of Crockford Base32 plus a Damm check symbol ADR-0033Dark by default everywhere; light is opt-in

Requirements

A numbered, verifiable catalogue with stable identifiers and a stage column that drives the plan.

01 · Functional 02 · Non-functional 03 · Security and privacy 04 · Stages and sequence

Reference data

The registries clients branch on, kept as data rather than prose.

problem-types.yaml — the RFC 9457 registry degraded-reasons.yaml — what got worse, and why label-media.yaml — label geometries

The design system

Binding, not a reference. One token source generates both the web stylesheet and the Compose theme, so the clients cannot drift apart. Dark is the shipped default on every platform and light is one click away; the breakpoints are Material 3 window size classes, so web and native agree on what “expanded” means. This website is built from it.

The system The brief behind it

Taking part

Contributing — what the project expects. The most valuable contribution today is a hole in the design. Security policy — never open a public issue for a vulnerability; use private reporting. Code of conduct — Contributor Covenant 3.0. Known plugins — a curated list, not a distribution channel.