Sol Nguyen

Hi, I'm

Sol Nguyen

Full-stack developer

  • Parent
  • Caregiver
  • Traveler

I build websites and apps from start to finish, from how they look to everything that makes them work behind the scenes.

My favorite part is shipping something that actually works and makes someone's day easier. I care about the small details: if a task can take one click instead of three, it should.

Lately I've been building with AI tools like Claude Code. They help me move faster, while I stay hands-on with how everything looks, works and gets tested.

Check out my latest and proudest creation:

ChronoRoam

Chrono for time, roam for travel.

A trip planner built around your days. Map out every day down to the minute or keep it loose, even add a flight you haven't booked yet. Name each day, like "Disneyland Day" or "Jet Lag Rest Day", so you know what today's about at a glance.

Save things you want to do, eat or buy, then move them onto a day. Every day shows the weather for wherever you'll be, worked out automatically from your flights and hotels: what it's usually like months ahead, then the real forecast as the day gets close. So the beach day can dodge the rain.

Pack with one simple checklist or bag by bag, so when you land at 11pm you know exactly which suitcase has the toothbrush.

Forward a booking email and ChronoRoam fills in the details. Get tips for where you're headed, like whether you need a visa or a plug adapter. Plan on your computer with the calendar view, then take it with you on your iPhone.

  • React
  • Node.js
  • Express
  • PostgreSQL
  • Claude & OpenAI
  • Stripe
  • iOS (Capacitor)
How it's built
  • React web app wrapped with Capacitor to ship the same code as a native iOS app
  • Node.js/Express REST API on Render with PostgreSQL through raw SQL (pg)
  • Inbound email: a Cloudflare Email Worker parses the MIME message and posts it to a secret-authenticated webhook
  • AI extraction runs on a low-cost model first, with deterministic checks for corrupted or incomplete output and a fallback to Claude
  • Rank-based location inference for accurate per-day weather: flight arrival > transit or directions > hotel > activity location, then carry-forward from the previous day, then first departure airport > trip destinations > place name in the trip title; late arrivals count from the next day, and geocoder matches more than 500 km from higher-ranked signals are rejected
  • Real forecasts inside Open-Meteo's ~16-day window; beyond it, a cached 3-year same-day average labeled as typical weather
  • Trip titles are matched against an offline set of ~1,750 place names before a single geocoding call, so unresolvable titles cost no network requests
  • Custom pointer-event drag and drop: long-press reordering with a drop-preview line, an edge auto-scroll loop, and background polling paused mid-drag
  • Shared cache-first lookups: every external lookup (AI trip tips, flights, geocoding, weather) checks stored results first and only calls the AI or API on a cache miss, so each answer is fetched once and reused by every user: repeat lookups load from the database instead of waiting seconds on an AI call, and cost per user falls as usage grows; weather is keyed to ~11 km grid cells to raise the hit rate, and "no result" answers are cached too
  • A low-cost model (~$0.000007 per call) first maps differently worded trip titles to one destination key, so "Tokyo Trip" and "Tokyo 2026" share a single cached Trip Tips answer instead of each paying for a search-grounded call
  • One weather cache feeds per-day weather, the home comparison and multi-city trips; static data like outlet types and airport coordinates is bundled rather than fetched
  • Flight lookups fall back across three providers (AeroDataBox, AviationStack, then GPT with web search), with monthly quota tracking that cache hits never consume
  • Payments through Stripe (web) and Apple In-App Purchase (iOS), both verified on the server before unlocking
  • Membership-based access, guest accounts that merge into a real account on sign-in, and abuse prevention that stops deleted accounts from re-claiming free credits (by email and device ID)
View the source on GitHub →
Visit chronoroam.app Download iPhone app

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Other Projects

May 2026

VigilKura

A web app for parents that listens during a child's screen time, shows a live transcript, and alerts you with a sound and an email when it hears a word on your list. Set a word list and time limit for each child, look back at what was said, and translate transcripts into your language. Works best in Chrome or Safari.

How it's built
  • React and Material UI frontend; speech is turned into text by the browser's built-in Web Speech API (Chrome or Safari)
  • Node.js/Express API on Render with a Neon PostgreSQL database
  • Speech-to-text runs in the browser, so the API only ever receives text and no audio is stored
  • Email goes through the Gmail API over HTTPS with a send-only OAuth scope, since Render's free tier blocks SMTP; alerts are rate-limited per child
  • Uses pagehide and navigator.sendBeacon to detect the tab closing, with a 30-second server-side grace period to tell a reload from a real exit
  • Transcripts are translated with OpenAI in batches of 40 lines using JSON output, and each batch is checked line for line so the translation stays aligned with the original
Visit app → Source on GitHub

Jun 2024

TripCheck

A packing checklist where you can put items inside other items, like a toiletry bag inside a suitcase, so your list is easier to organize and search than a notes app.

How it's built
  • React and Material UI frontend; Node.js/Express REST API with PostgreSQL
  • Nested items are stored as an adjacency list (parent_item_id) and rebuilt into a tree recursively; deletes cascade recursively through descendants
  • bcrypt password hashing and JWT auth; a user_checklists join table with owner/shared roles controls who can edit, share or delete
  • Integrates the Visual Crossing, ExchangeRate-API and Restful Countries APIs
Source on GitHub

Nov 2023

FlightCast

A flight search app that shows flight options and prices alongside the weather forecast for your destination, all in one place.

How it's built
  • Python and Flask app with server-rendered Jinja pages and vanilla JavaScript
  • Flight offers from the Amadeus API; the server handles the OAuth client-credentials token so secrets stay off the client
  • Visual Crossing for destination forecasts and ExchangeRate-API to convert EUR fares
  • PostgreSQL via Flask-SQLAlchemy models; session-based auth with bcrypt hashing and CSRF-protected Flask-WTF forms
Source on GitHub

See more of my work on GitHub →

About

Before I wrote code, I spent four and a half years as a CAD drafter, turning rough concepts into precise 3D designs and finding ways to make the work faster and cheaper. That habit of asking "how could this be simpler?" is what pulled me into software.

I completed Springboard's Software Engineering program in 2024 and have kept building since. A lot of my projects come from travel, because planning trips is where I kept running into problems worth solving.

Away from the keyboard, I'm a dad and a family caregiver. Both remind me that the best tools are the ones that quietly make life easier for the people using them.

Front-end

  • JavaScript
  • HTML
  • CSS
  • React
  • Redux
  • React Router
  • Material UI
  • jQuery
  • AJAX
  • Jinja

Back-end

  • Node.js
  • Express
  • Python
  • Flask
  • SQLAlchemy
  • SQL
  • PostgreSQL
  • REST APIs
  • Webhooks
  • OAuth
  • JWT & bcrypt auth

AI

  • OpenAI API
  • Claude API
  • Prompt engineering
  • Structured outputs
  • AI data extraction
  • Multi-model fallback
  • Output validation
  • Web search grounding
  • Response caching
  • AI translation

Tools & more

  • Git
  • GitHub
  • Jest
  • Jasmine
  • Data structures
  • Algorithms
  • Capacitor (iOS)
  • Stripe
  • Apple In-App Purchase
  • Web Speech API
  • Gmail API
  • Cloudflare
  • Render
  • Neon

Experience

  1. Jul 2024 – Present Seattle, WA

    Software Developer

    Personal Projects

    • Design, build and launch my own apps from start to finish, including ChronoRoam, a live trip planner for the web and iPhone. See Projects for more.
  2. Jan 2021 – Present

    Stay-at-Home Parent & Family Caregiver

    Family

    • Full-time parent and family caregiver; paid caregiver through Consumer Direct Care Network Washington (CDWA) since Jan 2025.
  3. Feb 2017 – Jul 2021 Renton, WA

    CAD Drafter

    Lumicor

    • Led a team of 8, including project managers, engineers and fabricators, turning submitted concepts and drawings into sketches, 3D renderings and design structures tailored to each client.
    • Managed projects from start to finish: concept design, design validation and analysis, hardware design, resin panel processing for manufacturing, product testing and delivery.
    • Increased profit margin by 300% through strategic vendor and fabrication tactics.
    • Pitched and introduced AutoCAD 3D and 3D rendering across drafting, sales and engineering, which increased sales through better visualization and reduced assembly errors.
    • Cut the time needed to complete projects by 50% by researching new approaches, creating templates and removing redundant work.
    • Reduced the yearly software renewal budget by at least $10,000 by eliminating SolidWorks and Inventor.

Education

  • Software Engineering Career Track

    Springboard

    Feb 2023 – Jun 2024

  • Associate of Applied Science, Engineering & Graphic Design Technology

    South Seattle College

    Sep 2014 – Jun 2016

Get in touch