Grant Fonseca

Full-Stack Software Engineer

Building scalable solutions with Python, React, Ruby on Rails, and modern AI integrations. Passionate about solving complex problems and delivering business value through code.

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Grant Fonseca
What I Offer

Services

From AI-powered automation to full-stack development and security engineering — I build solutions that move the needle.

AI Services

AI Integration & Automation

Build intelligent AI-powered tools and workflows that save time and scale your business. From custom LLM integrations and chatbots to fully automated content and data pipelines.

LLM APIsClaude / OpenAIPythonAutomationAgentic Workflows

Full-Stack Development

Custom web applications built for performance and longevity. Polished React/Next.js frontends paired with robust backends in Ruby on Rails or Python.

ReactNext.jsRuby on RailsPythonPostgreSQL

Data Engineering & Pipelines

Design and build reliable data integration systems, ETL pipelines, and API connectors that turn scattered raw data into actionable business insight.

PythonETL / ELTREST APIsGISPostgreSQL

Security Engineering

Harden your systems with security reviews, custom monitoring tools, and honeypot setups. Protect your infrastructure before incidents happen.

AWS SecurityHoneypotsNetwork AnalysisPythonIncident Response

Not sure what you need? Let's figure it out together.

Experience

Department Programmer Analyst

City of Santa Rosa | Water Department | Asset Management Team

Oct 2023 - Today

Created custom python program to continuously integrate data between two different asset management systems. Maintained, developed new features, and troubleshooted bugs in the existing code base for the integration.

PythonfmeGISPostmanvimgithubdata structures

Full-Stack Software Engineer

Orgchart Now

Nov 2021 - May 2023

Engineered solutions to bugs on the back-end code base pertaining to different data connectors (SAP XML, Bamboo HR, etc.). Designed & developed new features in react and javascript.

ReactPythonJavaScriptTailwindcssChrome Debugger

Full-Stack Java Software Developer

Crosscheck, inc.

May 2021 - Nov 2021

Developed Java Web Application to interact with data stored on AS400 server. Designed UI with a responsive hierarchical chart to be expandable and contractable.

SpringbootJavaThymeleafCSSHTMLJavaScript

Co-Founder/Software Engineer

BGCIndustry

Nov 2020 - May 2021

Designed and developed minimum viable product (MVP) for a centralized hub of background checking websites.

PythonFlaskHerokuBootStrapJavaScriptCSSHTMLBrowser AutomationWeb Scraping

Security Software Engineer Intern

23AndMe

May 2019 - Aug 2019

Created canary token/honeypot designed to notify security team when any attempts to authenticate with those credentials were made.

AWSPagerDutySlackPythonBash

Security Software Engineer Intern

ISD, County of Sonoma

Jan 2019 - May 2019

Designed & Implemented a C++ program to analyze network traffic and determine which hosts were trustworthy based on frequency of activity in network logs. Built using 2-3 trees, and the results were compiled into a whitelist of IP addresses.

C++2-3 TreesData StructuresCyber SecuritySecurity Incident Response PlanNetworking

Featured Projects

Pulse Consult

Pulse Consult

Full-Stack app built using Ruby on Rails, Postgresql, Docker, and Tailwind CSS. The app is a booking platform.

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CrossCheck Hub

Full-Stack app built using Java, Springboot, and Thymeleaf.

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Senior Research Project

Senior Research Project

I worked with my professor, Dr. Gondree, to develop a system of programmatically identifying when capture the flag events took place in a defcon CTF event.

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Android App School Project

Android App School Project

Security camera application that connected to a raspberry pi hosted webcam through a private twitch url I designed and developed in a school project.

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Professional Portfolio

Professional Portfolio

Portfolio web-app built using Next.js, React, Tailwind css.

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Free Consultation

Ready to Work Together?

Book a free 20-minute video call and let's talk about how I can help bring your idea to life — whether it's an AI integration, a new web app, or something in between.

No commitment. No pressure. Just a conversation.