Japonics / FINTECH

BANKA

A personal and family finance platform that connects budgets, goals, subscriptions, automation, and financial education.

System design Development Security
BANKA preview
Client: Japonics Year: 2026

Financial-clarity architecture

Where the project started

Banka keeps budgeting intent and real cash flow as two separate truths and treats investing as strictly read-only: the ledger, budgets, net worth, and a live eToro integration share one explainable data model instead of another disconnected dashboard.

Starting point

Users experience finance in fragments: accounts, categories, bills, subscriptions, and goals live in separate tools.

Direction taken

Banka requires strong authorization, privacy, and data-classification architecture. The core is a financial ledger, categories, goals, automation rules, and an insight layer that separates transaction facts from recommendations, with an eToro integration bringing in the investing context instead of Banka ever executing trades itself.

Business / Product

Problems and solutions

Each tile connects a real product tension with the decision that clarified the domain, UX, or operations.

Problem

Users experience finance in fragments: accounts, categories, bills, subscriptions, and goals live in separate tools.

Solution

Create a model that organizes everyday financial decisions instead of merely aggregating transactions.

Outcome Coherent finance domain map
Problem

The scope could easily become a feature list without one product, data, and ownership model.

Solution

Banka requires strong authorization, privacy, and data-classification architecture. The core is a financial ledger, categories, goals, automation rules, and an insight layer that separates transaction facts from recommendations, with an eToro integration bringing in the investing context instead of Banka ever executing trades itself.

Outcome Ledger and automation as separate bounded contexts
Problem

The project needed decisions that would stay readable after the first version: for users, the team, and further delivery.

Solution

Ledger and automation as separate bounded contexts. Privacy patterns for financial data.

Outcome Working eToro investing integration

Roles and competencies

The competencies this build required

Competencies are shown as ownership roles: CTO, Tech Lead, engineering, DevOps, cloud, security, and AI where they were part of the work.

01

Fractional CTO

Connecting the product thesis, domain risk, and priorities so technology supports business decisions instead of becoming a separate workstream.

Open competency
Scope
  • Product category and positioning
  • Scope priorities and risk
  • Decisions ready for founder or CTO review
Applied experience
  • Product thesis translated into technical priorities.
  • Risks framed in a language stakeholders can review.
02

Tech Lead

Shaping responsibility boundaries, domain modeling, and architecture decisions so the project can grow without drifting into an accidental monolith.

Open competency
Scope
  • Bounded contexts and ownership
  • Readable technical decisions
  • Roadmap without implementation chaos
Applied experience
  • Domain boundaries and decisions that remain reviewable after MVP.
  • Ownership model readable for later delivery stages.
03

Software Engineer

Turning the domain into screens, APIs, flows, and maintainable implementation with focus on clarity and post-MVP evolution.

Open competency
Scope
  • Backend and application contracts
  • UX surfaces ready for iteration
  • Code and maintenance model
Applied experience
  • Implementation tied to the real product workflow.
  • Contracts and code prepared for post-launch iteration.
04

DevOps Engineer

Designing delivery, observability, and operations so release, diagnostics, and recovery are part of the product.

Open competency
Scope
  • CI/CD and release readiness
  • Observability and production signals
  • Operations without manual rituals
Applied experience
  • Release, diagnostics, and recovery designed as product capabilities.
  • Production signals ready for maintenance without guessing.
05

Cloud Engineer

Choosing cloud, data, and integration foundations so scale, cost, and reliability are not added after the fact.

Open competency
Scope
  • Google Cloud and managed services
  • Data, events, and storage
  • Cost and operational control
Applied experience
  • Cloud choices tied to cost, scale, and data responsibility.
  • Integrations and storage treated as foundations, not add-ons.
06

Security Engineer

Financial data carries an explicit sensitivity classification and encryption at rest, and the non-execution boundary - Banka never places an order or moves money - is designed as a security control, not just a product limitation.

Open competency
Scope
  • Ledger and portfolio data classification with encryption at rest
  • Non-execution trust boundary: no orders, no money movement
  • GDPR-aligned export and deletion on user request
Applied experience
  • Privacy, roles, and auditability built into the product model.
  • Security visible in domain decisions, not only around the UI.

Stack by competency

Tech stack

The stack is grouped by competency so it shows both technology and responsibility: software, leadership, DevOps, cloud, security, and AI.

Software Engineer
  • .NET / ASP.NET Core
  • TypeScript
  • .NET MAUI mobile client
  • Angular web client
  • Domain logic engines
  • PostgreSQL
Tech Lead
  • Domain modeling
  • Rules-engine governance
DevOps Engineer
  • Google Cloud
  • OpenTelemetry
  • Cloud Logging
Cloud Engineer
  • Google Cloud Platform
Security Engineer
  • Privacy architecture
  • Data classification & encryption
  • GDPR data lifecycle
  • Non-execution trust boundary
.NET / ASP.NET Core .NET MAUI mobile client Domain logic engines Domain modeling Google Cloud Cloud Logging Privacy architecture GDPR data lifecycle .NET 8 GCP .NET MAUI eToro API GDPR export & deletion TypeScript Angular web client PostgreSQL Rules-engine governance OpenTelemetry Google Cloud Platform Data classification & encryption Non-execution trust boundary Event log Rules engine Angular Data classification & encryption at rest .NET / ASP.NET Core .NET MAUI mobile client Domain logic engines Domain modeling Google Cloud Cloud Logging Privacy architecture GDPR data lifecycle .NET 8 GCP .NET MAUI eToro API GDPR export & deletion
TypeScript Angular web client PostgreSQL Rules-engine governance OpenTelemetry Google Cloud Platform Data classification & encryption Non-execution trust boundary Event log Rules engine Angular Data classification & encryption at rest .NET / ASP.NET Core .NET MAUI mobile client Domain logic engines Domain modeling Google Cloud Cloud Logging Privacy architecture GDPR data lifecycle .NET 8 GCP .NET MAUI eToro API GDPR export & deletion TypeScript Angular web client PostgreSQL Rules-engine governance OpenTelemetry Google Cloud Platform Data classification & encryption Non-execution trust boundary Event log Rules engine Angular Data classification & encryption at rest