Kaiserslautern, Germany · open to senior roles

Systems that ship,
and the decisions behind them.

I'm Arib Yousuf — a senior software engineer with 9+ years building production backend and full-stack systems: banking switches, public-sector platforms, smart-city APIs. Most client code is under NDA, so this site shows the next best thing: how I decide.

C# / .NET CoreNode.js / TypeScriptReact / Next.jsM.Sc. CS · RPTU
architecture decision records

Client code is under NDA. Decisions aren't.

Each record below follows the ADR format engineers use in real codebases — context, decision, consequences. Ask me about any of them in an interview; I can go as deep as you like.

ADR-001 · bankingstatus: shipped · scale: 100K+ customers

Real-time SMS banking on a live transaction switch

Context

Bank of Punjab needed real-time balance, withdrawal, transfer and alert notifications driven directly off core banking activity — reliably, at scale, with zero tolerance for wrong balances.

Decision

Integrate the IRIS transaction switch with the SMS engine event-driven, not by polling. Map switch events to notification triggers with formatting, delivery and account routing as separate concerns.

Consequences

Sub-second alerts with no polling load on the core. Defensive handling of partial and duplicate transactions meant a wrong balance never shipped to a customer.

real-time alerts live for 100K+ customers
C#SQL Serverevent-drivenfull write-up →
ADR-002 · public-sectorstatus: shipped · scale: 220+ organizations

Multi-tenant election management platform

Context

Hundreds of organizations needed end-to-end elections — onboarding, voter records, election setup, reporting — each with strictly isolated data, on one platform.

Decision

.NET 6 on Clean Architecture with DDD: election rules modeled as first-class domain concepts, independent of delivery and storage. Tenant boundaries enforced at the domain layer, not the query layer.

Consequences

Per-tenant customization without forking logic. New organization onboarding became configuration, not development. Domain tests run without infrastructure.

automated election workflows across 220+ orgs
.NET 6Clean ArchitectureDDDmulti-tenant
ADR-003 · smart-citystatus: shipped · scale: 100K+ req/day

NEOM smart-city platform APIs

Context

Three smart-city platforms needed RESTful backends with clear domain separation, high availability, and room to grow independently — under aggressive timelines.

Decision

Modular .NET Core services over a shared kernel: each platform owns its domain, shares cross-cutting infrastructure (auth, logging, data access) instead of duplicating it.

Consequences

~40% faster delivery across the three platforms through reuse; 99.9% uptime at 100K+ daily requests. Automated tests at 90% coverage cut bug reports by more than half.

3 platforms, 99.9% uptime, 100K+ requests/day
.NET CoreMSSQLRESTperformance
ADR-004 · commercestatus: shipped · scale: 10K+ users

Full-stack grocery platform with payments

Context

A grocery business in Cyprus needed a consumer app and CRM handling real money — ordering, inventory, and payment processing — with a small team and no room for payment failures.

Decision

TypeScript/React front end over a hardened payment integration: idempotent order creation, explicit failure states, and reconciliation built in from day one rather than bolted on.

Consequences

99.99% payment success on $500K+ monthly volume; 4.5/5 user rating from 10K+ users. CRM efficiency up ~35% after the TypeScript rewrite.

$500K+/month processed at 99.99% success
TypeScriptReactpayments
ADR-005 · personal · AI toolingstatus: shipped · scale: shipping now

An AI coding agent whose server never sees your code

Context

A terminal coding agent must read source, edit files and run shell commands. Executing those server-side means every user's proprietary code and shell access transit a third party — disqualifying for most teams. And a "plan mode" enforced by prompt instructions is a suggestion, not a safety property.

Decision

The server defines schema-only tool contracts and holds no implementations; the CLI executes them locally, sandboxed to the project root, and auto-continues the agent loop. Plan and Build modes swap the model's exposed toolset between read-only and full write/shell — enforced at the contract layer, not the prompt.

Consequences

Source and shell access never leave the machine. The model cannot edit in Plan mode because no write tool exists to call. Token-metered billing rides on idempotent usage events with balance-gating before the model call.

agent harness over Anthropic & OpenAI models
TypeScriptBunHonoPrismaagentsfull write-up →
capabilities

The stack, by depth.

Bold means daily-driver depth — the things I'd be comfortable owning in production tomorrow.

Backend
  • C# / .NET Core
  • Node.js / Express
  • REST API design
  • RabbitMQ / event-driven
  • SignalR / real-time
Frontend
  • TypeScript
  • React / Next.js
  • Vue.js
  • Tailwind CSS
  • Flutter (mobile)
Data & Ops
  • SQL Server / PostgreSQL
  • EF Core / query tuning
  • Docker
  • Azure
  • CI/CD · Git
changelog

Nine years, four countries, one throughline: production.

Every role below ended with systems still running.

2022 — present · Kaiserslautern
Senior Software Developer
Layer Four GmbH

Flutter Web enterprise platforms for German clients: a ~27k-LOC field-service and admin portal (Regiocom AMS) and an eight-module GIS platform with an embedded ArcGIS map and Azure AD SSO. Also Next.js/.NET project-management and HR systems.

2020 — 2021 · remote
Senior Software Engineer
Green Light Labs

Architected .NET Core APIs for three NEOM smart-city platforms (ADR-003): 100K+ daily requests, 99.9% uptime, modular architecture that cut delivery time ~40%.

2019 — 2020
Software Engineer
Binaro

Full-stack grocery platform serving 10K+ users in Cyprus (ADR-004), an immigration case-management CMS in React/.NET Core, and a real-time survey platform.

2018 — 2021 · four countries
Freelance Software Engineer
Independent · incl. Lodestone

Delivered complete systems end-to-end: the multi-tenant election platform for 220+ organizations (ADR-002), the O-WILL legacy-planning app for UAE, and a bi-directional QuickBooks ↔ Salesforce sync engine.

2017 — 2019 · Karachi
Software Engineer
Curve Technologies

Banking and healthcare systems for major Pakistani institutions: reconciliation software for UBL (.NET/Oracle/SignalR), an insurance policy platform for IGI, and the SIUT hospital app with donation and zakat features.

2016 — 2017 · Karachi
Software Engineer
M3 Technologies

Enterprise and telecom systems in C#/.NET — including the Bank of Punjab IRIS transaction-switch integration behind real-time SMS banking (ADR-001), and an SMS complaint engine for a utility serving 30M people.

M.Sc. Computer Science
RPTU Kaiserslautern-Landau, Germany
completed 2026 · focus: intelligent systems
B.Sc. Computer Science
Karachi Institute of Economics & Technology
2017 · GPA 3.5/4.0 · Dean's Honor Student · Teaching Assistant
final record

Decision: we should talk.

Open to senior backend and full-stack roles in Germany — remote or on-site. The fastest channel is email; I'm happy to walk through any decision record in as much depth as you want.