Chicago · Open to AI automation, workflow & AI specialist roles

I build AI tools and automations that people actually use.

I'm Nick Castro. I turn ideas into live websites and web tools, fast. A business site, a web app, even a kids' book.

Skills

  • Prompt design & testing
  • AI workflow automation
  • AI agents with live search
  • SEO, schema & GA4 / Search Console
  • Web security basics
  • Explaining AI to non-technical people
  • Bilingual English/Spanish

Things I've built

Bar chart: late filers vs similar-sized stocks over 3 months, −3.90% in 2012–2020 and −4.16% in 2021–2026
Case Study

I tested 15 offbeat stock signals the hard way. One survived.

Result: Late filers lagged similar-sized stocks by about 4% over 3 months, in both 2012–2020 (−3.90%) and 2021–2026 (−4.16%).

Snowpack, box office, bird flu, cattle, power outages, the Suez Canal, insider buys, and six SEC filing signals didn't pass (five failed, one is still under review). I used size-matched comparison groups, survivorship checks, and rules picked on 2012–2020 then confirmed on 2021–2026. Education only, not advice.

Read the case study →
Screenshot of The Other Data homepage, a free alternative-data stock tool, with a search box to look up a ticker
Alternative Data Tool

The Other Data

Result: Visitors share it, and it's already drawing people in from Facebook and Instagram.

A free tool that explains stocks with alternative data — the offbeat, indirect signals most people miss. Look up a ticker and get plain-English AI summaries of news and quotes, plus offbeat public data like paperboard output, airport lines, and FDA reports. Education only, not predictions. Built for insight, not candlestick-chart reading.

How I built it

Problem: Most stock tools assume you can read charts. I wanted plain-English explanations of the offbeat signals behind a stock.

Approach: I pulled market data from the Finnhub and Tiingo APIs and used Gemini to turn news and quotes into short summaries. I used AI assistants to plan and build it, and tested the output by hand.

Key decision: I left out candlestick charts on purpose and built the page around insight instead.

Try it →
Screenshot of the Does AI Know My Business? homepage, a free AI visibility check
AI Tool

Does AI Know My Business? (AI Visibility Check)

Result: 10+ AI visibility checks completed, and it has already captured its first lead.

A free tool that shows whether AI recommends a local business. An AI agent runs live Google searches on screen, then gives a 0–100 score, the competitors AI names instead, a check of the business's website, and a fix plan with ready-to-paste schema code. It works in English and Spanish. Built with Gemini + Google Search grounding, Vercel, and JavaScript.

How I built it

Problem: Local business owners don't know whether AI assistants recommend them, or why a competitor gets named instead.

Approach: An AI agent runs live Google searches with Gemini's Search grounding, then scores the result 0–100. I tested and refined the prompts so scores stay consistent and explainable.

Key decision: The searches play live on screen so owners see how the score was reached, and every result comes with a fix plan and ready-to-paste schema code. It works in English and Spanish.

Try it → Read the case study →
Screenshot of the SiteSafeCheck homepage, a free website security check, with the headline Is your website leaving the door open? and a box to enter a website address
Website Security Tool

SiteSafeCheck

Result: Live and scanning sites; I ran it across all my own sites and fixed every finding.

A free, passive website security check for small businesses. Enter your site and get a plain-English grade on HTTPS, security headers, email spoofing protection (SPF/DKIM/DMARC), info leaks, and cookie safety — with AI explaining each issue and how to fix it.

How I built it

Problem: Small businesses rarely know if their website has basic security gaps.

Approach: It runs passive checks on HTTPS, security headers, SPF/DKIM/DMARC email records, info leaks and cookies, then AI explains each issue and the fix in plain English.

Key decision: It only runs passive checks: nothing intrusive, so it's safe to run on any site.

Try it →
Screenshot of the How AI Works for Kids homepage, where Pip the tiny robot AI says hi next to the headline Teach a tiny AI
Kids' Learning App

How AI Works for Kids

Result: 19+ lessons finished by kids so far.

Interactive lessons where kids ages 6–10 learn how AI works by teaching a tiny AI named Pip. There are 15 lessons in two sections, and each one has a picture story with read-aloud, a hands-on game (including a real nearest-neighbor classifier that learns a kid's secret sorting rule, and a next-word model that co-writes a story), a quick check, and a badge, plus a printable certificate at the end. It's kid-safe by design: no ads, accounts, chatbot, or kid data (COPPA-friendly). I'm testing it with my sons, Nathan (8) and Nolan (11). Built with Next.js, TypeScript, Tailwind, and Vercel, with SEO, schema, GA4, and Search Console.

How I built it

Problem: Kids use AI every day, but most explanations are too abstract for ages 6–10.

Approach: Fifteen lessons, each with a read-aloud story and a hands-on game, including a real nearest-neighbor classifier and a next-word model. Built with Next.js, TypeScript, Tailwind and Vercel, with AI assistants for planning and building.

Key decision: It's kid-safe by design: no ads, no accounts, no chatbot and no kid data. I tested it with my sons.

Try it →
Screenshot of the A&A Professional Roofers website homepage
Business Website

A&A Professional Roofers

Result: Live site with a Get a Free Quote button and tap-to-call at the top.

A full website for A&A Professional Roofers LLC, a Chicago roofing company owned by a friend. It lays out their services (repairs, replacements, inspections, storm damage, flat roofs), shows a gallery of their work and the suburbs they serve, and puts a "Get a Free Quote" button and a tap-to-call phone number at the top of the page. It also has a Spanish-speaking callout so the owners reach more of their customers.

How I built it

Problem: A friend's Chicago roofing company needed a site that turns visitors into quote requests.

Approach: I built the full site with AI assistants, then set up SEO, schema markup and analytics.

Key decision: The "Get a Free Quote" button and tap-to-call number sit at the top of the page, and a Spanish-speaking callout helps them reach more customers.

Visit site → Bilingual sites for Chicago businesses →
Screenshot of the Roblox Idea Generator web app
Web App

Roblox Idea Generator

Result: 800+ game ideas generated, and 3,500+ appearances in Google search.

A free tool that helps Roblox developers decide what game to build next. Pick a genre (or go random) and get an idea built from a setting, a mechanic, and a twist, plus a core loop, a monetization plan with suggested Robux prices, a retention hook, a scope estimate, and a free one-page design doc. I started it for my sons, Nolan and Nathan.

How I built it

Problem: My sons wanted help deciding which Roblox game to build next.

Approach: I designed prompts that combine a setting, a mechanic and a twist, then expand them into a full plan. I built and deployed it as a web app with AI assistants.

Key decision: Every idea comes with a core loop, monetization with Robux prices, a scope estimate and a one-page design doc, not just a title.

Try it →
Cover of The Smart Soccer Ball Mystery: Machine Learning for Kids, Book 1, by Nick and Nancy Castro
Children's Book

The Smart Soccer Ball Mystery

The Smart Soccer Ball Mystery: Machine Learning for Kids – Book 1 is a 24-page picture book for ages 6–10 that I co-wrote with Nancy Castro. A boy named Nolan gets an AI soccer ball that gives terrible advice, and he learns it was trained on bad examples. The story teaches kids how AI learns from data, and why good data matters. Order a signed copy, or get it on Amazon.

Get the book →

About me

I'm Nick Castro. I'm a builder who ships. I take an idea and turn it into a live site people can actually use, and I care most about the result: a page that loads fast, looks right on a phone, and gets people to take action. I'm not a classically trained developer.

How I work: I ship with AI assistants for planning and building, then I own the product, the polish, and whether it actually works for people.

So far I've built an alternative-data stock tool (The Other Data) that surfaces offbeat market signals most people miss, a free tool that checks whether AI recommends a local business, a free website security check for small businesses, interactive lessons that teach kids how AI works, a business website for a local roofing company, a free game-idea tool for Roblox developers, and a children's book that explains machine learning. I also produce AI Tools Pulse, a short daily podcast about new AI tools. I'm looking for my next project, whether that's a role on a team or a website for your business.

Need a website, or have a role I'd be a good fit for?

Tell me a bit about what you need and I'll get back to you within a day.