Engineering Portfolio · Real Systems & Code

What I have built. Problems I have solved.

A portfolio of production architectures, financial models, event-driven outbox pipelines, and local-first AI tools. Each study distinguishes verified implemented features from external dependencies and prototypes.

8Verified Systems

4Core Domains (AI, Finance, Full-Stack, Research)

100%Audited Codebases & Source Inspection

Finance & AnalyticsImplemented & Verified (Local Workspace)

#01

Finance Tools — DCF Valuation

Deterministic Discounted Cash Flow valuation engine with Excel & JSON reconciliation

The Problem

Financial valuation assumptions are frequently hidden in spreadsheet cells or opaque web models, making sensitivity reviews difficult before calculating enterprise and equity value.

What I Built

Engineered a local DCF application connecting financial data inputs, assumption review, deterministic WACC and cash flow projections, and dual-format report generation.

Architecture & Data Pipeline

[ Financial Inputs & Drivers ]
            │
            ▼
┌───────────────────────────────┐
│     FastAPI DCF Core Engine   │
│  - Unlevered FCF Projection   │
│  - WACC & Cost of Capital     │
│  - Gordon Growth & Multiples  │
└───────────────┬───────────────┘
                │
        ┌───────┴───────┐
        ▼               ▼
[ Excel Worksheets ]  [ JSON Snapshot ]

Verified Outcomes:Deterministic 5-year projections; Gordon Growth & EV/EBITDA terminal values; instant zero-drift Excel export.

PythonFastAPIReactPostgreSQLFinancial Modeling

Read Case Study →GitHub Repository ↗

AI & AutomationImplemented & Tested (Database Outbox Monolith)

#02

Signal Desk — Lead Agent

Durable event-driven lead routing pipeline with PostgreSQL outbox & WhatsApp state machine

The Problem

Inbound customer inquiries from disparate forms often result in dropped context, missing consent records, and uncoordinated manual follow-up without audit trails.

What I Built

Designed and implemented inbound lead normalization, PostgreSQL transactional outbox jobs, token signature verification, and owner WhatsApp template routing.

Architecture & Data Pipeline

[ Inbound Lead Submission ]
            │ (HMAC Token Signed)
            ▼
┌───────────────────────────────┐
│   PostgreSQL Atomic Commit    │
│   ├── leads table             │
│   └── lead_outbox (sheets/wa) │
└───────────────┬───────────────┘
                │
                ▼ (Advisory Lock Worker)
┌───────────────────────────────┐
│     Worker Outbox Queue       │
│  ├── Google Sheets Adapter    │
│  └── WhatsApp Signed Callback │
└───────────────────────────────┘

Verified Outcomes:Atomic persistence receipt; exponential backoff retries (30s to 1hr); zero silent data loss under network failure.

TypeScriptNode.jsPostgreSQLZodTransactional Outbox

Read Case Study →GitHub Repository ↗

Full-Stack EngineeringImplemented Architecture (Spatial Monolith)

#03

FastCharger — EV Discovery

Geospatial electric vehicle charging locator with PostGIS spatial indexing & bounded ingestion

The Problem

EV owners in high-density regions face fragmented station directories with slow spatial querying and outdated connector compatibility details.

What I Built

Constructed discovery UI, station query filters, spatial indexing pipelines, rate-limiting middleware, and security headers.

Architecture & Data Pipeline

[ User Location / Search ]
            │
            ▼
┌───────────────────────────────┐
│      Hono Discovery API       │
│   - Bounded Spatial Bounding  │
│   - Connector & Speed Filters │
└───────────────┬───────────────┘
                │
                ▼
┌───────────────────────────────┐
│   PostGIS Spatial Database    │
│   - ST_DWithin Geospatial     │
│   - Static Station Snapshot   │
└───────────────────────────────┘

Verified Outcomes:Sub-50ms indexed spatial proximity queries; rate-limited discovery endpoints; strict zero-leakage security boundaries.

Next.jsHonoPostgreSQLPostGISGeospatial Search

Read Case Study →GitHub Repository ↗

AI & AutomationImplemented & Sandboxed (Python / FastAPI)

#04

Prompt BI — Natural-Language Analytics

Natural-language query engine over relational SQL with AST security sandboxing & explainable charts

The Problem

Business and executive teams face multi-day turnaround lags waiting for data teams to hand-write routine operational SQL queries.

What I Built

Constructed natural-language analysis workspace with database schema metadata injection, SQL AST validation, and interactive dashboard components.

Architecture & Data Pipeline

[ Natural Language Question ]
            │
            ▼
┌───────────────────────────────┐
│    Prompt & Schema Context    │
│   - Injected Schema Metadata  │
│   - Read-Only User Constraint │
└───────────────┬───────────────┘
                │
                ▼
┌───────────────────────────────┐
│   AST Security SQL Validator  │
│   - Blocks DROP/UPDATE/DELETE │
│   - Enforces LIMIT Clamping   │
└───────────────┬───────────────┘
                │
                ▼
[ Read-Only Replica DB ] ──► [ Plotly Charts & Summaries ]

Verified Outcomes:100% read-only AST safety validation; zero manual SQL required for routine queries; real-time explainable query outputs.

ReactFastAPISQLAlchemyText-to-SQLAST Validation

Read Case Study →GitHub Repository ↗

Additional Production Architectures & Tools

Specialized engines, local inference pipelines, and scientific research systems.

AI & AutomationImplemented Prototype (FastAPI & Next.js)

Invoice OCR Extractor

Structured invoice document parsing with PaddleOCR and field confidence review

Manual data entry from PDF and scanned invoices is labor-intensive, error-prone, and slow across accounting and procurement workflows.

FastAPINext.jsPaddleOCRSQLite

Explore System & Code →Repo ↗

AI & AutomationImplemented Tool (Python / Apple Silicon MLX)

SEOJEV / Laya

Autonomous technical SEO audit agent using graph signals and local Apple Silicon MLX inference

SEO audits produce massive spreadsheets of disconnected crawl issues that sit unprioritized and unexecuted by development teams.

PythonFastAPIApple Silicon MLXNetworkX

Explore System & Code →Repo ↗

Full-Stack EngineeringArchitecture Foundation (Node.js Workspace)

Omnichannel AI Platform

Modular microservices architecture for multi-channel customer communications and AI agent routing

Managing customer communications across email, webchat, and messaging platforms creates duplicated logic and fragmented user profiles.

TypeScriptFastifyMySQLRedis

Explore System & Code →Repo ↗

ResearchResearch Account (OIST Internship)

OIST — Graph Neural Network Research

Scientific literature synthesis & Graph Neural Network representations for ecological food webs

Complex ecological food webs exhibit non-linear predator-prey dynamics and trophic cascades that standard tabular modeling fails to represent accurately.

GNNsPythonNetworkXComputational Biology

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