Sanitized engineering case studies about reliable domain systems, modular platforms, local-first data, testing, security, and delivery.
Maintained documentation
This repository explains engineering decisions and verification practices. It is not a substitute for the current inspectable code linked from my GitHub profile.
My work is backend-focused and often sits where business rules, data, integrations, and operational constraints meet. The recurring challenge is not merely implementing a happy path. It is changing behavior without losing compatibility, separating authority from derived state, making side effects recoverable, and proving that a change is safe enough to ship.
The case studies cover PHP/Symfony domain systems, TypeScript platform boundaries, Python and TypeScript local-data tools, Java host integration, and responsible AI-assisted delivery. Technologies are included where they explain a decision; the extended map is in Capabilities.
These case studies describe real engineering work using sanitized architecture, synthetic examples, and original diagrams. They omit proprietary code, operational data, and identifying organization details.
| Case study | Focus |
|---|---|
| Evolving Domain Rules in a Long-Lived Backend | Changing intertwined rules through explicit boundaries, focused tests, migrations, staged delivery, rollback, and production diagnosis. |
| A Modular TypeScript Platform | Separating domain logic, API contracts, web concerns, persistence, and operational safeguards as a system grows. |
| Trustworthy Local Data Systems | Provenance, append-only evidence, uncertainty, deterministic reconstruction, migrations, indexing, and rollback. |
| Verified AI-Assisted Engineering | Keeping scope, decisions, validation, security, and acceptance under human control. |
- Failure-Closed Java Host Integration describes lifecycle ownership, readiness gates, bounded recovery, packaging, and verification around a third-party desktop host.
- Trading-System and Automation Evolution follows a historical Electron and Node.js experiment from direct integration toward clearer boundaries, durable state, simulation, and operational safeguards.
Each page separates context, system boundaries, decisions, failure modes, verification, and limitations. Public repositories are linked only when their source can be inspected. Non-public work is represented with newly written explanations, original diagrams, and synthetic examples rather than copied source.
Claims are deliberately qualitative unless a result is reproducible from public material. A test strategy or migration plan is evidence of engineering practice; it is not converted into an invented scale or business-impact number.
- Domain change: make rule ownership and ordering explicit before changing behavior.
- Reliable delivery: connect acceptance criteria to focused tests, full gates, rollout, and rollback.
- Data trust: preserve provenance and distinguish authoritative records from rebuildable projections.
- Secure integration: fail closed on missing authority, isolate credentials, and bound side effects.
- Operational clarity: make state, failure, recovery, and remaining uncertainty observable.
- Responsible tooling: use AI assistance inside a reviewable, human-owned engineering process.
The documentation is maintained as the public portfolio evolves. Historical systems remain historical; updating their explanation does not imply current compatibility or maintenance.
New material must continue to meet the same evidence, privacy, accessibility, and truthful-status standards before it joins the navigation.