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👋 Welcome to my portfolio

Julius Matheka
Charles

Software Engineer · Data Engineer · AI & ML Developer

Results-driven Software & Data Engineer with hands-on experience across the full data lifecycle — from pipeline design and SQL analytics to Python backend development and BI reporting. Building reliable, scalable systems with AI/ML integration.

About Me

Turning complex data into actionable insights and building reliable, scalable systems

I'm a Software & Data Engineer with hands-on experience across the full data lifecycle — from pipeline design and SQL analytics to Python backend development and BI reporting. I specialise in turning complex data into actionable business insights and building reliable, scalable systems.

With a Computer Science foundation and professional certifications in Software Engineering and Data Science, I've built a career across data engineering, backend development, and AI/ML integration — always focused on writing clean, maintainable code and delivering impactful solutions.

I bring a strong foundation in Agile delivery, cloud-native tools, and AI/ML integration. I'm always eager to take on new challenges and collaborate on projects that push the boundaries of what's possible.

Data Engineering

PostgreSQL · ETL/ELT · Airflow · Kafka · pgvector

AI / ML Integration

LangChain · OpenAI · RAG · Semantic Search · Claude

BI & Analytics

Power BI · Tableau · Dashboards · DAX · Data Modeling

Python Backend

Django · DRF · FastAPI · Celery · pytest

3+

Years Experience

5+

Professional Roles

20+

Technologies Mastered

100%

Commitment

Skills & Expertise

A comprehensive overview of my technical skills and proficiency levels

Data & SQL

PostgreSQL92%
MySQL80%
SQL (Advanced)95%
ETL / ELT Pipelines88%
Apache Airflow82%
Apache Kafka75%
Data Warehousing85%
pgvector78%

BI & Analytics

Power BI88%
Tableau82%
Data Modeling85%
Reporting Dashboards90%
DAX78%

Python

Django / DRF95%
FastAPI85%
Pandas / NumPy82%
Celery80%
pytest85%
Shell Scripting72%

AI / ML

LangChain88%
OpenAI (GPT-4o)90%
TensorFlow75%
RAG Systems88%
Vector Embeddings82%
Semantic Search85%
Claude API80%

Frontend

React / Next.js85%
TypeScript78%
JavaScript88%
Tailwind CSS90%
HTMX72%
HTML / CSS92%

DevOps

Docker88%
GitHub Actions / CI-CD85%
Linux80%
Git / GitHub92%
Agile / Scrum85%
Redis78%

Key Projects

A showcase of my recent work in AI integration, data engineering, and full-stack development

Prepzi — Smart Meal Planning App

2025 – Present

AI-powered meal planning that reduces food waste by 90%. Generates personalized weekly/monthly plans from your inventory, with smart shopping lists, 10+ cuisines, dietary preferences, and offline-first sync.

React NativeExpoTypeScriptFirebase FirestoreFirebase AuthRedux ToolkitTanStack QuerySpoonacular APINativeWind

Agents47 — AI Agent Platform

2024 – Present

Built scalable AI agent platform with RAG knowledge bases (PostgreSQL/pgvector), async pipelines (Celery/Redis), and real-time chat at <3s latency.

Django 5.x / DRFPostgreSQL / pgvectorLangChainOpenAI / ClaudeDockerGitHub ActionsCelery / Redis

LezMarket — AI Website Conversion Optimizer

2024

SaaS tool that scores homepages against persuasion principles, generates AI recommendations, and stores structured analysis history per user.

Next.jsSupabase (PostgreSQL)OpenAI GPT-4oTypeScriptTailwind CSS

Synovae — AI Job Matching Platform

2024

Semantic CV-to-job matching engine across 2,400+ live roles using LLM embeddings, with automated application tracking in Supabase.

Next.jsSupabase (PostgreSQL)OpenAI / LLMsTypeScriptTailwind CSS

Work Experience

My professional journey in software development, data engineering, and BI analytics

Junior Python Data Engineer

Maesk Group, KenyaOn-site
Sep 2025 - Present

Designed and implemented end-to-end data pipelines in Python and SQL — covering raw ingestion, staging, transformation, and analytics layers across PostgreSQL databases.

Built and scheduled Apache Airflow DAGs to automate recurring ETL jobs, replacing manual processes and improving data freshness for downstream consumers.

Engineered a semantic job-matching pipeline using Python, LangChain, and pgvector — parsing CVs and vectorising content for similarity search across 2,400+ live listings.

Implemented incremental loading patterns (upsert / ON CONFLICT DO UPDATE) and run logging to support efficient, restartable pipeline execution at scale.

Delivered a RAG-powered knowledge base using PostgreSQL/pgvector and LangChain, achieving sub-3-second query latency under load in production testing.

PythonPostgreSQLApache AirflowLangChainpgvectorSQLETL PipelinesRAG

Junior Python Developer

Paystack Remote
Aug 2024 – June 2025Internship — SQL & Data Analysis

Wrote complex SQL queries across PostgreSQL databases to extract, clean, and analyse business datasets for weekly management reporting.

Built and maintained ETL pipelines that pulled data from multiple source systems into a central data warehouse, reducing manual data preparation time by 35%.

Created data quality checks using SQL (NULL validation, duplicate detection, row count reconciliation) to ensure pipeline integrity across all reporting tables.

Collaborated with senior analysts to design dashboard-ready summary views and aggregation tables consumed by Power BI reports.

Documented SQL query logic and pipeline steps, improving team knowledge sharing and onboarding efficiency.

PostgreSQLSQLETL PipelinesPower BIData Warehousing

Data Analyst Intern (SQL)

Windle International, KenyaOn-site
January 2023 – March 2024Internship — SQL & Data Analysis

Wrote complex SQL queries across PostgreSQL databases to extract, clean, and analyse business datasets for weekly management reporting.

Built and maintained ETL pipelines that pulled data from multiple source systems into a central data warehouse, reducing manual data preparation time by 35%.

Created data quality checks using SQL (NULL validation, duplicate detection, row count reconciliation) to ensure pipeline integrity across all reporting tables.

Collaborated with senior analysts to design dashboard-ready summary views and aggregation tables consumed by Power BI reports.

Documented SQL query logic and pipeline steps, improving team knowledge sharing and onboarding efficiency.

PostgreSQLSQLETL PipelinesPower BIData Warehousing

Education & Certifications

My academic background and professional certifications

Education

Professional Certification — Software Engineering

ALX AfricaRemote
Jan 2024 – Feb 2025

Full-stack development, algorithms, Django/React, Java/Spring Boot.

Professional Certification — Data Science

Moringa SchoolRemote
Jan 2023 – Nov 2023

Machine Learning, ETL pipelines, Python, SQL, TensorFlow, Tableau.

B.Sc. Computer Science

Kenyatta UniversityNairobi, Kenya
2018 – 2022

Strong foundation in algorithms, data structures, software engineering, and systems design.

Certifications

ETL and Data Pipelines with Shell, Airflow & Kafka

IBM

2024

Data Warehousing and BI Analytics

IBM

2024

Linux Commands and Shell Scripting

IBM

2024

Get In Touch

I'm always open to discussing new projects, creative ideas, or opportunities to be part of your visions.