Julio is available for hire
Hire JulioJulio Marquez
Verified Expert in Engineering
Full-stack Developer
Valencia, Spain
Toptal member since July 15, 2020
Bio
Julio ships healthcare apps end to end, from event-driven back ends and DevEx to React Native and design system work. He has 5+ years at Bicycle Health, a US OUD telehealth provider serving 50,000+ patients in 32 states, where he built the patient app, two admin portals, and a multi-tenant correctional health platform on GCP with Sentry observability and on-call rotation. Julio's experience includes a fractional engagement at a dental clinic startup, bringing his total experience to 16+ years.
Portfolio
Carousel Soft LLC
PostgreSQL, Python, Django, APIs, React Native, WebSockets, Twilio, Expo...
Odentitus SL
PHP, Filament PHP, Inertia, React, TypeScript, Tailwind CSS, SaloonPHP...
Bicycle Health Inc
JavaScript, TypeScript, Node.js, React Native, Next.js, GraphQL...
Experience
- Full-stack - 16 years
- Code Architecture - 10 years
- Cloud - 10 years
- Cloud Infrastructure - 7 years
- Mobile Apps - 6 years
- Healthcare - 6 years
- Team Leadership - 5 years
- Project Management - 5 years
Preferred Environment
GitHub, Git, MacOS, Ubuntu, Visual Studio Code (VS Code), Full-stack, NPM, TypeScript, PHP, Clean Architecture
The most amazing...
...thing I've shipped is the at-home urine drug screening flow on the Bicycle Health patient app. The clinical team called it "very high impact."
Work Experience
Full-stack Software Engineer with MVP Build Support
2026 - 2026
Carousel Soft LLC
- Took over a vibe-coded prototype and rebuilt it into a production-ready MVP now serving real bands: Django 6/DRF back end, OpenAPI-generated clients, and Expo React Native apps across iOS, Android, and web.
- Designed and shipped real-time group messaging on Django Channels and Redis with cursor-based catch-up and gap detection, sized for 6,000 users across 20+ bands and 300-member topics.
- Delivered a sheet-music distribution pipeline that converts uploaded PDF scores into per-part images through background tasks with Celery, with presigned uploads to S3-compatible storage and offline downloads on mobile.
- Implemented multi-channel notifications (push, email, and SMS via Twilio) with per-user channel preferences, SMS segment-aware quotas, and idempotent, rate-limited email delivery.
- Engineered an offline-first mobile experience with a persisted client-side query cache, optimistic writes with rollback, and retry-safe APIs designed for unreliable rehearsal-field networks.
- Created a WhatsApp-style messaging experience with group and topic chats, threaded replies, emoji reactions, message editing and deletion, media attachments, content reporting, and smart push suppression for actively viewed conversations.
- Deployed a single-artifact pnpm monorepo to DigitalOcean App Platform with separate HTTP and WebSocket services, Celery workers, pre-deploy migrations, and a Cloudflare-hosted PWA.
- Rebuilt the Django admin into a least-privilege ops panel with credential redaction, domain-service-mediated writes, and guards against cascading deletes.
- Hardened the production stack for rehearsal-hour traffic spikes by tuning PgBouncer transaction pooling and exempting hot read paths from per-request transactions to free pooled connections.
- Built a k6 load-testing suite simulating rehearsal-hour peaks against authenticated REST and WebSocket flows, driving production instance sizing, connection pool limits, and API throttle budgets.
Technologies: PostgreSQL, Python, Django, APIs, React Native, WebSockets, Twilio, Expo, DigitalOcean, Real-time Data, Messaging, Cloudflare, PWA, iOS, Android, Push Notifications, Twilio API, SMS, Music, Django REST Framework, Celery, Redis, TypeScript, React, REST APIs, OpenAPI, Progressive Web Applications (PWAs), Prompt Engineering, Responsive UI, Application State Management, Offline Data Synchronization, Supabase Auth, Agentic AI, Cloud Deployment, Authorization, Bug Fixes, Monorepos, Telemetry, Software Engineering, Agentic Coding, SEO Tools, Product Ownership, Design, AI Development, Cloud Storage, Stress Testing, REST
Full-stack & Founding Engineer (Fractional)
2025 - 2026
Odentitus SL
- Led the migration of a WordPress MVP to a custom Laravel 12, Inertia.js, and React 19 platform after the founder confirmed product-market fit.
- Owned the entire stack as sole technical leader for a non-technical founder, running weekly syncs and writing technical handover docs so the client keeps full ownership of the codebase.
- Built EMR and accounting API integrations via SaloonPHP, decoupling third-party systems behind a typed service layer.
- Shipped the internal admin dashboard with role-based access for clinic staff, appointment management, and patient records.
- Set up the CI/CD pipeline with 100% code and type coverage from day one (GitHub Actions, Pest, PHPStan, and TypeScript).
- Paired with the brand designer to translate a new identity from Figma into a pixel-perfect, responsive UI in Tailwind CSS with a token-first design system, owning UI primitives and component selection.
- Drove build vs buy decisions and infrastructure choices, keeping the stack lean to fit an early-stage budget.
Technologies: PHP, Filament PHP, Inertia, React, TypeScript, Tailwind CSS, SaloonPHP, Laravel Livewire, Vite, PostgreSQL, WordPress, Search Engine Optimization (SEO), Local SEO, Yoast SEO, A/B Testing, SaaS, Full-stack Development, Software Architecture, VPS, Laravel Forge, REST APIs, Web Architecture, Web Application Architecture, API Integration, MVP Design, Minimum Viable Product (MVP), Refactoring, Content Management Systems (CMS), Performance, Website Performance, Core Web Vitals, CI/CD Pipelines, Cloudflare, Electronic Health Records (EHR), Electronic Medical Records (EMR), PHPStan, Docker, Responsive Design, Migration, Claude Code, Fractional CTO, Sentry, Resend, Page Speed Optimization, Cloud, API Development, RESTFul APIs, Test-driven Development (TDD), Linux, Figma to React, User Experience (UX), CTO, Artificial Intelligence (AI), Zapier, Workflow Automation, API Architecture, Orchestration, Regulated Industries, Business Rules Engine, Microservices Architecture, ECMAScript (ES6), CRM, Google Analytics, Code Review, Code Auditing, Laravel, Shadcn, Communication, Real-time Data, Data Privacy, Playwright, TanStack Table, Chart.js, Healthcare & Insurance, Health Insurance, Dental Services Organizations, AI Architecture, Google Maps API, Customer Relationship Management (CRM), Leaflet, Cloud Infrastructure, Scalability, Data Integrity, UX Design, Coding, Web App Development, Automation, AI-generated Code, Responsive, Google Antigravity, ChatGPT, Healthcare, SMS, Logging, Data Science, Acceptance Criteria, Back-end Architecture, Clean Architecture, Messaging, User Authentication, Shadcn UI, Vitest, Whisper, Twilio API, Performance Optimization, Codex, Database Design, Webhooks, Healthtech, GDPR, Medical Software, Machine Learning, JSON, Stripe API, System Architecture, Health, Healthcare IT, WCAG 2, Web Content Accessibility Guidelines (WCAG), Technical SEO, Databases, Progressive Web Applications (PWAs), Back-end Performance, Data Analytics, Videos, Elasticsearch, Supabase, TOTP, Uptime Monitoring, UI Design, Content Delivery Networks (CDN), Geospatial Analytics, Spatial Analysis, Startup Consulting, Technical Project Management, Tools, SQLite, i18next, TestFlight, PostHog, TanStack Router, Zod, OXC (Oxlint), Bun, NGINX, OpenTelemetry, Lighthouse, Accessibility, Observability, Meilisearch, Consulting, Advisory, B2C, Third-party Integration, Enterprise Integration, PHP 8, SendGrid, Tailwind UI, React Testing Library, Webpack, Streaming, Video Streaming, Web, Notion API, Third-party APIs, Data Visualization, Alpine.js, TALL Stack, AWS Lambda, Amazon Elastic Container Service (ECS), WebSockets, Mobile Apps, Startups, Software System Architecture Development, Video Processing, Video APIs, Scheduling, Scheduling Tools, Google Calendar, Technical Architecture, Leadership, Prompt Engineering, Data Encryption, Responsive UI, Application State Management, Offline Data Synchronization, Agentic AI, Cloud Deployment, Authorization, Bug Fixes, Monorepos, Telemetry, Server-side Rendering (SSR), Software Engineering, Agentic Coding, SEO Tools, Google Analytics 4 (GA4), Product Ownership, Design, Web Scraping, Data Pipelines, Puppeteer, Selenium, AI Development, Cloud Storage, Transcoding, EMR, REST, Georeferencing
Senior Full-stack Software Engineer & Tech Lead
2021 - 2026
Bicycle Health Inc
- Built the multi-tenant correctional health platform from scratch: a React Native tablet app, two admin portals, and an OAuth2/OIDC auth system with role-based access control.
- Shipped 20+ features on the patient app from spec to App Store and Play Store release, including LaunchDarkly-gated rollouts, Sentry-tagged builds, and Mixpanel post-launch funnels.
- Designed the event-driven lab automation platform using Cloud Functions, Pub/Sub, and Cloud Tasks, removing a manual bottleneck and letting the clinical team scale operations without new headcount.
- Built provider-availability ranking algorithms that optimized patient scheduling across time zones and specialties.
- Led the observability rollout by integrating Sentry across back end, front end, and mobile for distributed tracing, profiling, and custom OpenTelemetry instrumentation for Datastore, replacing fragile log-based alerting.
- Reduced monthly production incidents from 8 to 1 on the on-call rotation by tightening alert thresholds, adding tracing coverage, and resolving recurring failure modes at the root cause.
- Cut cloud database operational costs by 50% through deep entity profiling and query analysis, identifying high-cost backup and read patterns and driving targeted data-access optimizations.
- Rebuilt the pharmacy finder with geohash-bounded expanding-radius queries (5 to 80 miles), cutting response time from 10s to 500ms and eliminating state-wide timeouts on Datastore, then drove the follow-on NoSQL-to-PostgreSQL migration.
- Led the at-home urine drug screening project end to end, including spec, architecture, code review, and release plan, with India-based contractors and a US engineering team.
- Paired with designers on styling guidelines, theme tokens, and UI library selection across web and mobile; mentored junior engineers and authored implementation specs that standardized deployment, observability, and code-review patterns.
Technologies: JavaScript, TypeScript, Node.js, React Native, Next.js, GraphQL, Google Cloud Platform (GCP), Google Cloud Functions, Google Cloud Tasks, Pub/Sub, PostgreSQL, Google Cloud Datastore, Prisma, Docker, OAuth 2, OAuth, OpenID Connect (OIDC), Role-based Access Control (RBAC), OpenTelemetry, Sentry, GitHub Actions, GitHub Workflows, Continuous Deployment, Continuous Delivery (CD), Continuous Monitoring, LaunchDarkly, Mixpanel, BigQuery, Expo, EAS, Event-driven Architecture, Microservices, Geospatial Data, Tailwind CSS, SaaS, Remix, React Router, Gemini, GitHub Copilot Chat, Back-end, Serverless, Python, Git, REST APIs, Sass, NPM, Express.js, Pandas, Amazon S3 (AWS S3), React, Firebase, Jest, Project Management, NumPy, Test-driven Development (TDD), Redux, Clean Code, Teamwork, GPS, ESLint, Testing, Research, Serverless Architecture, Cloudflare, Performance, Website Performance, Firebase Cloud Functions, CI/CD Pipelines, Deployment, Infrastructure, Incident Handling, Incident Response, Incident Management, Debugging, Legacy Code, Legacy Software, HIPAA, Healthcare Software, MVP Design, Refactoring, Web Application Architecture, Full-stack Development, Mobile App Development, A/B Testing, Mobile App Testing, Mobile Apps, Claude Code, Web Development, Early-stage Startups, Architecture, Technical Leadership, SDKs, Swagger, OpenAPI, Telemetry, QR Codes, Requirements Analysis, Solution Architecture, SQL, Data Analysis, Product Management, Artificial Intelligence (AI), Algorithms, Mobile First, API Integration, Mobile, User Interface (UI), Documentation, Technical Writing, MySQL, HIPAA Compliance, Stripe, Claude API, AI Integration, JSON Web Tokens (JWT), NestJS, Software Architecture, Large Language Models (LLMs), Security, OpenAI, Anthropic, Authentication, Push Notifications, iOS, Android, App Store, Google Play Store, Dashboards, Redis, CSV Import, full stack JavaScript, Google APIs, AI Tools, Cursor AI, Claude, APIs, Back-end Development, Front-end Development, Event-driven Systems, Middleware, Validation, Regulated Industries, Business Rules Engine, Fastify, Page Speed Optimization, Cloud, API Development, Google Cloud, AI Agents, RESTFul APIs, Linux, User Experience (UX), Minimum Viable Product (MVP), Workflow Automation, API Architecture, Orchestration, Cross-platform App Development, Mobile Development, Compliance, Multi-tenant Architecture, Multi-tenant SaaS, Microservices Architecture, Vite, ECMAScript (ES6), CRM, Google Analytics, Code Review, Code Auditing, Shadcn, Communication, Cross-platform, Real-time Data, Data Privacy, Celery, FastAPI, Playwright, TanStack Table, Chart.js, Healthcare & Insurance, Health Insurance, AI Architecture, Google Maps API, Customer Relationship Management (CRM), Leaflet, Cloud Infrastructure, Scalability, Data Integrity, PostGIS, Stripe Connect, Enterprise Integration Patterns (EIP), Mobile UI Design, UX Design, Coding, Web App Development, Automation, AI-generated Code, Responsive, Material UI, Google Antigravity, ChatGPT, Twilio, Quality Assurance (QA), Healthcare, SMS, Logging, Data Science, Acceptance Criteria, Back-end Architecture, Clean Architecture, Messaging, User Authentication, Shadcn UI, tRPC, Vitest, Drizzle ORM, Drizzle, Whisper, Twilio API, Performance Optimization, B2B, Database Design, Image Processing, Webhooks, Fast Healthcare Interoperability Resources (FHIR), Healthtech, Typeform, Medical Software, Machine Learning, JSON, Stripe API, System Architecture, React Native for Web, Health, HL7 FHIR Standard, Healthcare IT, Electronic Health Records (EHR), WCAG 2, Web Content Accessibility Guidelines (WCAG), Infrastructure as Code (IaC), Databases, Education Technology (Edtech), Jira, Progressive Web Applications (PWAs), Back-end Performance, Data Analytics, Videos, Geofencing, TOTP, Uptime Monitoring, UI Design, Content Delivery Networks (CDN), Geospatial Analytics, Spatial Analysis, Startup Consulting, Technical Project Management, Tools, SQLite, i18next, TestFlight, WatermelonDB, BetterAuth, Storybook, TanStack Router, Zod, NGINX, Lighthouse, Accessibility, Observability, Advisory, B2C, Pulumi, Third-party Integration, Enterprise Integration, SendGrid, Tailwind UI, React Testing Library, Webpack, Streaming, Video Streaming, Webflow, Web, Google Sheets, Google Sheets API, Third-party APIs, Data Visualization, AWS Lambda, Amazon Elastic Container Service (ECS), WebSockets, Startups, Software System Architecture Development, Google Calendar API, Video Processing, Video APIs, Scheduling, Scheduling Tools, Google Calendar, Technical Architecture, Leadership, gRPC, Distributed Systems, Data Encryption, Responsive UI, Application State Management, Apollo, Apollo Server, GitHub Copilot, GraphQL API, Offline Data Synchronization, Agentic AI, Cloud Deployment, Authorization, Bug Fixes, Monorepos, Server-side Rendering (SSR), Zustand, Software Engineering, Agentic Coding, Product Ownership, Design, Data Pipelines, Puppeteer, Selenium, AI Development, Cloud Storage, Transcoding, EMR, Stress Testing, REST, Georeferencing
Full-stack Software Engineer (Telehealth Platform)
2020 - 2021
Bicycle Health Inc
- Built the Flowspace UDS automation pipeline, enabling the clinical support team to scale operations without additional headcount.
- Migrated Firebase Cloud Functions to a CLI-based deployment workflow, replacing GUI configuration and improving maintainability across the engineering team.
- Introduced Next.js and Tailwind CSS to the front-end stack, then wrote the component patterns and migration guide adopted across two later admin tools.
- Built the mobile app v1 back end from scratch, delivering chat restoration, default pharmacy lookup, and provider management APIs on schedule.
- Owned the in-app urine drug screening and pregnancy test feature end to end across mobile, back end, and admin tooling.
- Migrated provider management from JavaScript-driven logic to a database-backed admin portal, improving data integrity and reducing manual configuration.
- Designed and shipped the walk-in appointment system and recommended-availability algorithm, improving patient access to care.
- Served as first responder on the on-call rotation for P0 production incidents while maintaining feature velocity on concurrent projects.
- Executed the Athena EHR API migration, transitioning core integrations to a new interface while preserving data integrity and uptime.
- Delivered discharge automation, induction tooling, and consent-form workflows for clinical compliance within 2 to 4 week timelines.
Technologies: Node.js, TypeScript, React, JavaScript, GraphQL, React Native, Google Cloud Platform (GCP), Firebase Cloud Functions, Next.js, CI/CD Pipelines, GitHub Workflows, Deployment, Infrastructure, Incident Handling, Incident Response, Incident Management, Debugging, Tailwind CSS, Legacy Code, Legacy Software, HIPAA, Healthcare Software, REST APIs, RESTFul APIs, Google Cloud Datastore, Front-end, Full-stack, HTML5, Back-end, Serverless, Python, Git, NPM, Express.js, Amazon S3 (AWS S3), Firebase, Jest, Project Management, Redux, Docker, Clean Code, Teamwork, GPS, ESLint, Testing, Research, Serverless Architecture, Performance, Website Performance, Sentry, MVP Design, Refactoring, Web Application Architecture, Full-stack Development, Mobile App Development, A/B Testing, Mobile App Testing, Mobile Apps, Geospatial Data, Microservices, Web Development, Early-stage Startups, Architecture, Technical Leadership, SDKs, Swagger, OpenAPI, Telemetry, QR Codes, Requirements Analysis, Solution Architecture, SQL, Data Analysis, Product Management, Algorithms, Mobile First, API Integration, Mobile, User Interface (UI), Documentation, Technical Writing, MySQL, HIPAA Compliance, Stripe, Claude API, AI Integration, OAuth, JSON Web Tokens (JWT), Software Architecture, Security, Authentication, Push Notifications, iOS, Android, App Store, Google Play Store, Role-based Access Control (RBAC), Dashboards, Redis, CSV Import, full stack JavaScript, Google APIs, AI Tools, APIs, Back-end Development, Front-end Development, Event-driven Systems, Middleware, Validation, Regulated Industries, Business Rules Engine, Fastify, Page Speed Optimization, Cloud, API Development, Google Cloud, AI Agents, Test-driven Development (TDD), Linux, User Experience (UX), Minimum Viable Product (MVP), API Architecture, Orchestration, Cross-platform App Development, Mobile Development, Compliance, Multi-tenant Architecture, Multi-tenant SaaS, Microservices Architecture, ECMAScript (ES6), CRM, Google Analytics, Code Review, Code Auditing, Communication, Cross-platform, Real-time Data, Data Privacy, FastAPI, Playwright, Healthcare & Insurance, Health Insurance, Google Maps API, Customer Relationship Management (CRM), Cloud Infrastructure, Scalability, Data Integrity, PostGIS, Enterprise Integration Patterns (EIP), UX Design, Coding, Web App Development, Automation, Responsive, Material UI, Twilio, Quality Assurance (QA), Healthcare, SMS, Logging, Data Science, Acceptance Criteria, Back-end Architecture, Clean Architecture, Messaging, User Authentication, Shadcn UI, Twilio API, Performance Optimization, B2B, Database Design, Image Processing, Webhooks, Fast Healthcare Interoperability Resources (FHIR), Healthtech, Typeform, Medical Software, JSON, Stripe API, System Architecture, Health, HL7 FHIR Standard, Healthcare IT, Electronic Health Records (EHR), OAuth 2, Infrastructure as Code (IaC), Databases, Back-end Performance, Data Analytics, Geofencing, TOTP, Uptime Monitoring, UI Design, Content Delivery Networks (CDN), Geospatial Analytics, Spatial Analysis, Technical Project Management, Tools, i18next, TestFlight, Storybook, NGINX, OpenTelemetry, Accessibility, Observability, B2C, Third-party Integration, Enterprise Integration, Tailwind UI, React Testing Library, Webpack, Webflow, Web, Google Sheets API, Third-party APIs, Data Visualization, AWS Lambda, Amazon Elastic Container Service (ECS), Startups, Software System Architecture Development, Google Calendar API, Video Processing, Video APIs, Scheduling, Scheduling Tools, Google Calendar, Technical Architecture, Leadership, gRPC, Distributed Systems, Data Encryption, Responsive UI, Application State Management, Apollo, Apollo Server, GraphQL API, Offline Data Synchronization, Agentic AI, Cloud Deployment, Authorization, Bug Fixes, Monorepos, Server-side Rendering (SSR), Zustand, Software Engineering, Design, Cloud Storage, EMR, Stress Testing, REST, Georeferencing
Software Developer
2020 - 2021
Toptal Client (Oil & Gas Analytics)
- Migrated an oil-and-gas analytics company's WordPress blog to a Nuxt.js static site with a Sanity headless CMS for editorial workflows.
- Reworked the main marketing site from Figma to pixel-perfect, responsive HTML and CSS.
- Deployed the site to AWS Amplify Hosting and guided the client through cutover and DNS handoff.
Technologies: Vue, Nuxt.js, CSS, Git, Content Management Systems (CMS), Headless CMS, Responsive Design, Search Engine Optimization (SEO), Analytics, Amazon Web Services (AWS), WordPress, Front-end, Full-stack, HTML5, Jamstack, Figma, Figma to HTML, Sanity Studio, CI/CD Pipelines, AWS Amplify, SSG, Core Web Vitals, Cross-browser Compatibility, DNS, Back-end, Serverless, JavaScript, Node.js, NPM, Amazon S3 (AWS S3), TypeScript, Docker, Clean Code, Teamwork, ESLint, Testing, Website Performance, Deployment, Debugging, Legacy Software, Full-stack Development, Microservices, Web Development, Mobile First, API Integration, User Interface (UI), Documentation, Technical Writing, Authentication, full stack JavaScript, APIs, Back-end Development, Front-end Development, Middleware, Validation, Page Speed Optimization, Vercel, Cloud, API Development, RESTFul APIs, Linux, Figma to React, User Experience (UX), API Architecture, Pinia, Coding, Web App Development, Responsive, Logging, Back-end Architecture, Clean Architecture, Performance Optimization, JSON, Technical SEO, Progressive Web Applications (PWAs), Supabase, TOTP, UI Design, Content Delivery Networks (CDN), Technical Project Management, Tools, Consulting, B2C, Third-party Integration, Web, Third-party APIs, AWS Lambda, Startups, Responsive UI, Bug Fixes, Monorepos, Software Engineering, SEO Tools, Cloud Storage
Lead Engineer
2015 - 2019
Bazzite LLC
- Led engineering for 40+ greenfield web and mobile projects, including dynamic web apps, eCommerce, and corporate sites.
- Executed, as a team, different projects, including dynamic web, eCommerce sites, and back-office sites.
- Established CI/CD pipelines, code-review standards, and onboarding patterns, plus scoping, QA, and handoff processes that kept delivery predictable across concurrent projects.
Technologies: Jest, Firebase, Vuex, TypeScript, Amazon S3 (AWS S3), GitHub, React, HTML, Pandas, Express.js, Django ORM, NPM, Sass, Django, REST APIs, Git, Python, Node.js, CSS, JavaScript, Serverless, Open Source, Vue, Nuxt.js, Bootstrap, jQuery, Back-end, HTML5, Front-end, Full-stack, Next.js, CSS3, PHP, PWA, PostgreSQL, NumPy, Flask, Clean Code, Teamwork, Testing, Website Performance, Deployment, Infrastructure, Debugging, Legacy Code, Legacy Software, MVP Design, Refactoring, Web Application Architecture, Full-stack Development, Web Development, Early-stage Startups, Architecture, Technical Leadership, SDKs, Requirements Analysis, Solution Architecture, SQL, Data Analysis, Product Management, Algorithms, Mobile First, API Integration, Mobile, User Interface (UI), Documentation, Technical Writing, MySQL, Software Architecture, Authentication, iOS, Android, App Store, Google Play Store, Dashboards, Redis, CSV Import, full stack JavaScript, Netlify, APIs, Back-end Development, Front-end Development, Middleware, Validation, Fastify, Page Speed Optimization, Vercel, Cloud, API Development, RESTFul APIs, Test-driven Development (TDD), Linux, User Experience (UX), Minimum Viable Product (MVP), CTO, Zapier, Workflow Automation, API Architecture, Orchestration, Cross-platform App Development, Mobile Development, Microservices Architecture, Google Analytics, Code Auditing, Laravel, GPS Tracker, GIS, Maps, Communication, Cross-platform, Real-time Data, Data Privacy, Celery, FastAPI, Cloud Infrastructure, GeoDjango, PostGIS, UX Design, Coding, Web App Development, Automation, Responsive, Logging, Data Science, Acceptance Criteria, Back-end Architecture, Clean Architecture, User Authentication, Performance Optimization, B2B, Database Design, Webhooks, JSON, System Architecture, Technical SEO, Databases, Progressive Web Applications (PWAs), Bitbucket, Videos, Elasticsearch, TOTP, UI Design, Content Delivery Networks (CDN), Spatial Analysis, Startup Consulting, Technical Project Management, Tools, i18next, eCommerce, Consulting, B2C, Third-party Integration, SCSS, SendGrid, Webpack, Streaming, Video Streaming, Web, Third-party APIs, AWS Lambda, Startups, Software System Architecture Development, Video Processing, Video APIs, Technical Architecture, Leadership, Responsive UI, Application State Management, GraphQL API, Bug Fixes, Monorepos, Server-side Rendering (SSR), Software Engineering, SEO Tools, Product Ownership, Design, Web Scraping, Cloud Storage, Stress Testing, REST
Full-stack Developer
2008 - 2016
Freelance
- Created a front-end admin template that earned +4.7 stars out of 5 on Themeforest; it was fully responsive and cross-browser with Bootstrap and jQuery. Included easy-to-use components and a huge collection of plugins.
- Built 20+ high-performance websites, including dynamic web applications, eCommerce sites, and corporate sites.
- Released a front-end admin template that maintained a 4.7/5 rating on ThemeForest, fully responsive and cross-browser, with a large component and plugin library.
- Delivered back-end systems in PHP and Python with MySQL and PostgreSQL, and integrated third-party APIs (Google Maps, Google Analytics, and Facebook).
Technologies: Jest, Vuex, TypeScript, GitHub, React, HTML, Pandas, Express.js, Django ORM, NPM, Sass, Django, REST APIs, Git, Python, Node.js, CSS, JavaScript, Serverless, Open Source, Vue, Nuxt.js, Bootstrap, jQuery, Back-end, HTML5, Front-end, Full-stack, Angular, CSS3, PHP, PWA, Flask, Refactoring, Web Development, Mobile First, API Integration, User Interface (UI), Documentation, MySQL, Authentication, Dashboards, full stack JavaScript, Netlify, APIs, Front-end Development, Middleware, Validation, Fastify, Page Speed Optimization, API Development, RESTFul APIs, Linux, User Experience (UX), API Architecture, Code Review, Code Auditing, GPS Tracker, GIS, Maps, Coding, Web App Development, Responsive, Logging, Data Science, Clean Architecture, JSON, System Architecture, Technical SEO, Databases, Bitbucket, TOTP, B2C, SCSS, Web, Third-party APIs, Responsive UI, Application State Management, Bug Fixes, Software Engineering, REST
Scientific Programmer
2014 - 2015
Geochemical Research and Engineering, Inc.
- Worked on a research team applying numerical methods to fluid and gas injection problems in reservoir simulation.
- Built computational simulation modules for aqueous speciation and mineral precipitation, translating patented multi-year research into a product used for reservoir analysis in the oil industry.
- Worked in a high-performance team focused on computer simulations to solve the oil industry's most outstanding and difficult engineering calculations and computing processes.
Technologies: REST APIs, Git, Python, Back-end, C#, MATLAB, Visual Studio, Full-stack, NumPy, Pandas, GPS, Data Analysis, Documentation, Validation, Regulated Industries, Linux, Code Review, GIS, Maps, GPS Tracker, Data Privacy, PostGIS, Coding, Logging, Data Science, Database Design, JSON, System Architecture, Databases, Third-party APIs, Bug Fixes, Software Engineering, .NET
Research Assistant
2010 - 2015
Satellite Geodesy and Seismotectonics Laboratory
- Researched and developed computational simulations in seismotectonics.
- Planned, executed, processed, and analyzed georeferenced data from GPS measurements.
- Adjusted geodetic control networks using satellite techniques and computational models.
- Co-authored multi-year research findings published in the Geophysical Journal International (Oxford University Press).
Technologies: Pandas, Jupyter, REST APIs, Git, Python, JavaScript, Back-end, CSS3, NumPy, GPS, Data Analysis, Documentation, Validation, Regulated Industries, Linux, Orchestration, Code Review, GIS, Maps, GPS Tracker, Data Privacy, PostGIS, Coding, Data Science, JSON, System Architecture, Databases, Geospatial Analytics, Spatial Analysis, Third-party Integration, Third-party APIs, Bug Fixes, Software Engineering
Experience
Staccato: Marching Band Management App
https://apps.apple.com/us/app/staccato-music-collaboration/id6774253415Staccato is a multi-tenant platform that helps marching band directors run their programs by distributing sheet music, messaging members in real time, managing rosters and sections, and sending announcements via push, email, and SMS. I inherited the project as a vibe-coded prototype and, as the sole engineer, rebuilt it into a production-ready MVP that now serves real bands and live traffic. The back end is Django 6 with DRF, Channels (WebSockets), Celery, and PostgreSQL, deployed on DigitalOcean App Platform with media on Cloudflare R2. The mobile app is built with Expo and React Native, sharing one codebase across iOS, Android, and a web PWA, with an OpenAPI-generated client and a persisted query cache for offline-first caching and optimistic writes. Notable features include a WhatsApp-style chat with threaded replies, emoji reactions, message editing, and offline catch-up; a background PDF conversion pipeline that turns uploaded scores into per-part images; a custom landscape music viewer built on Skia; and quota-aware SMS delivery through Twilio.
Odéntitus – Dental Practice Management and Marketing Platform
https://odentitus.com?ref=toptalI built the entire digital platform for a dental clinic startup in Valencia, Spain, including the marketing website and internal practice management tools.
I started with a WordPress MVP to validate the market, then migrated to a custom Laravel 12 platform after product-market fit, enabling programmatic SEO, A/B testing, and EMR integration. Working closely with the brand designer, I translated a new identity from Figma into a pixel-perfect, responsive UI in Tailwind CSS using a token-first design system. The local SEO strategy included dedicated landing pages per service and neighborhood, targeting 37,000+ monthly search volume. I also built the internal admin dashboard on FilamentPHP to extend the clinic's external EMR, automating appointment management and patient workflows.
I integrated EMR and accounting systems via SaloonPHP, using a typed service layer to eliminate manual data entry. Later, I migrated the dashboard front end to Inertia.js and React 19 to overcome FilamentPHP's flexibility limits as the product grew. I set up CI/CD pipelines with 100% code and type coverage and led all technology decisions as the sole technical leader for a non-technical founder.
I started with a WordPress MVP to validate the market, then migrated to a custom Laravel 12 platform after product-market fit, enabling programmatic SEO, A/B testing, and EMR integration. Working closely with the brand designer, I translated a new identity from Figma into a pixel-perfect, responsive UI in Tailwind CSS using a token-first design system. The local SEO strategy included dedicated landing pages per service and neighborhood, targeting 37,000+ monthly search volume. I also built the internal admin dashboard on FilamentPHP to extend the clinic's external EMR, automating appointment management and patient workflows.
I integrated EMR and accounting systems via SaloonPHP, using a typed service layer to eliminate manual data entry. Later, I migrated the dashboard front end to Inertia.js and React 19 to overcome FilamentPHP's flexibility limits as the product grew. I set up CI/CD pipelines with 100% code and type coverage and led all technology decisions as the sole technical leader for a non-technical founder.
Bicycle Health Patient App – Telehealth Mobile Platform for OUD Treatment
https://apps.apple.com/en/app/bicycle-health/id1560854220The patient-facing mobile app for Bicycle Health, a leading U.S. OUD telehealth provider. The app is the primary touchpoint for patients managing their recovery: appointment scheduling, in-app chat with care teams, support groups, prescription management, billing, profile management, and lab results.
I owned the at-home urine drug screening (UDS) workflow end to end, a multi-step flow with guided photo capture, submission tracking, and provider tooling to interpret and act on results. Clinical leadership called it "very high impact" for scaling operations.
I led the Sentry integration across mobile, front end, and back end (crash reporting, performance profiling, distributed tracing), replacing fragile log-based alerting and reducing the weekly incident count. I migrated analytics to Mixpanel for data-informed product decisions, implemented LaunchDarkly-driven A/B testing for in-app messaging and announcements, and contributed to the Support Groups feature, including notification settings and a Datastore-to-PostgreSQL data migration.
I owned the at-home urine drug screening (UDS) workflow end to end, a multi-step flow with guided photo capture, submission tracking, and provider tooling to interpret and act on results. Clinical leadership called it "very high impact" for scaling operations.
I led the Sentry integration across mobile, front end, and back end (crash reporting, performance profiling, distributed tracing), replacing fragile log-based alerting and reducing the weekly incident count. I migrated analytics to Mixpanel for data-informed product decisions, implemented LaunchDarkly-driven A/B testing for in-app messaging and announcements, and contributed to the Support Groups feature, including notification settings and a Datastore-to-PostgreSQL data migration.
Personal Website and SEO-optimized Multilingual Content Platform
https://juliomarquez.comjuliomarquez.com is my personal site and writing platform, built to double as a working showcase of a modern, edge-rendered web stack.
Stack:
Astro for static generation, Tailwind CSS for the design system, Cloudflare Pages Functions for serverless endpoints, fully localized in English and Spanish with a content layer for posts and prompts. I owned it end to end: architecture, front end, serverless back end, design system, build pipeline, and deployment.
Performance and SEO:
• Lighthouse score of 100 across Performance, Accessibility, Best Practices, and SEO.
• Edge caching for static assets, image format optimization using AVIF and WebP, and stable font metrics to avoid layout shift.
• Code quality through strict TypeScript, automated testing, and CI/CD on every push to main. The site also serves as the canonical home for technical writing indexed under my own name rather than on a third-party platform.
Stack:
Astro for static generation, Tailwind CSS for the design system, Cloudflare Pages Functions for serverless endpoints, fully localized in English and Spanish with a content layer for posts and prompts. I owned it end to end: architecture, front end, serverless back end, design system, build pipeline, and deployment.
Performance and SEO:
• Lighthouse score of 100 across Performance, Accessibility, Best Practices, and SEO.
• Edge caching for static assets, image format optimization using AVIF and WebP, and stable font metrics to avoid layout shift.
• Code quality through strict TypeScript, automated testing, and CI/CD on every push to main. The site also serves as the canonical home for technical writing indexed under my own name rather than on a third-party platform.
Nuxt.js Optimized Images - OpenSource
https://github.com/juliomrqz/nuxt-optimized-imagesA Nuxt.js module I authored that automates image optimization across JPEG, PNG, SVG, WebP, and GIF, designed to drop into any Nuxt build pipeline without runtime cost.
What it does:
• Up to 60% reduction in image payload sizes through format-specific compression and lossless re-encoding.
• Faster page loads via progressive image rendering and JPEG/PNG to WebP conversion on the fly for browsers that support it.
• Image resizing, low-quality image placeholder (LQIP) generation, and dominant-color extraction for above-the-fold UX patterns.
• Content-hashed filenames for long-term CDN and browser caching.
• Inlining of small images to cut HTTP requests on first paint.
I authored and maintained the module: API design, image processing pipeline, Nuxt module integration, and documentation.
What it does:
• Up to 60% reduction in image payload sizes through format-specific compression and lossless re-encoding.
• Faster page loads via progressive image rendering and JPEG/PNG to WebP conversion on the fly for browsers that support it.
• Image resizing, low-quality image placeholder (LQIP) generation, and dominant-color extraction for above-the-fold UX patterns.
• Content-hashed filenames for long-term CDN and browser caching.
• Inlining of small images to cut HTTP requests on first paint.
I authored and maintained the module: API design, image processing pipeline, Nuxt module integration, and documentation.
Mapset
https://www.youtube.com/watch?v=orNVuOp31LcMapset was a cloud-based screen designer for mainframe coding languages, used in banking and insurance to design the screens that customer-facing operators interact with. The product became 15x faster than legacy mainframe tooling, while staying lower-cost and accessible to non-experts.
I designed the project architecture and built the back end. I led front-end development in close collaboration with mainframe engineers who owned the banking and insurance domain knowledge, translating their requirements into a web application with a dynamic interface that leveraged modern browser capabilities to support the core screen design workflow.
For the file conversion pipeline, I chose a serverless execution model to avoid server overhead: on-demand scaling, parallelism across long-running conversion jobs, and lower per-operation costs than a long-lived back end. I tested and documented the system end to end to meet the security and stability requirements of regulated customer information, including the audit trail expected by enterprise banking customers.
I designed the project architecture and built the back end. I led front-end development in close collaboration with mainframe engineers who owned the banking and insurance domain knowledge, translating their requirements into a web application with a dynamic interface that leveraged modern browser capabilities to support the core screen design workflow.
For the file conversion pipeline, I chose a serverless execution model to avoid server overhead: on-demand scaling, parallelism across long-running conversion jobs, and lower per-operation costs than a long-lived back end. I tested and documented the system end to end to meet the security and stability requirements of regulated customer information, including the audit trail expected by enterprise banking customers.
Statusfy | A Marvelous Open-source Status Page System
https://github.com/juliomrqz/statusfyStatusfy is an open-source status-page system designed for easy deployment across common hosting targets. It generates status pages as progressive web applications following a JAMstack architecture, using static generation for fast cold loads.
The project was designed as a cheaper and simpler alternative to hosted SaaS status pages, offering better performance, stronger security through a smaller attack surface, lower hosting costs, and more flexible deployment options for teams already using JAMstack stacks.
I authored the entire project, including the original architecture, back end, front end, visual identity, and a CLI that drives the build and authoring workflow. The project has earned 2,600+ GitHub stars.
The project was designed as a cheaper and simpler alternative to hosted SaaS status pages, offering better performance, stronger security through a smaller attack surface, lower hosting costs, and more flexible deployment options for teams already using JAMstack stacks.
I authored the entire project, including the original architecture, back end, front end, visual identity, and a CLI that drives the build and authoring workflow. The project has earned 2,600+ GitHub stars.
The North Andes and the Caribbean and South American Plate Interaction
I worked for four years as a research assistant in the Satellite Geodesy and Seismotectonics Laboratory at Simon Bolivar University (Caracas, Venezuela), on a study of the interaction between the North Andes plate and the Caribbean and South American plates in northwestern South America.
The input data came from GPS geodesy stations and regional seismic records. My work covered statistics, time-series analysis, geodetic control-network adjustment, and the interpretation of third-party research. I built and ran the computational simulations that turned raw GPS measurements into plate-velocity vectors and tectonic-stress maps for the study region.
The research went through a rigorous review process and was published in Geophysical Journal International (Oxford University Press, on behalf of the Royal Astronomical Society and the Deutsche Geophysikalische Gesellschaft).
The input data came from GPS geodesy stations and regional seismic records. My work covered statistics, time-series analysis, geodetic control-network adjustment, and the interpretation of third-party research. I built and ran the computational simulations that turned raw GPS measurements into plate-velocity vectors and tectonic-stress maps for the study region.
The research went through a rigorous review process and was published in Geophysical Journal International (Oxford University Press, on behalf of the Royal Astronomical Society and the Deutsche Geophysikalische Gesellschaft).
Education
2006 - 2014
Bachelor's Degree in Geophysical Engineering
Simon Bolivar University - Caracas, Venezuela
Certifications
SEPTEMBER 2023 - PRESENT
Cloud Digital Leader
Platzi INC
SEPTEMBER 2023 - PRESENT
Google Cloud Platform
Platzi INC
MARCH 2014 - PRESENT
Latin America Representative
American Association of Petroleum Geologists
OCTOBER 2013 - PRESENT
Student Chapter Excellence Award
Society of Exploration Geophysicists
SEPTEMBER 2013 - PRESENT
Leadership Symposium Travel Grant Award
Chevron and the Society of Exploration Geophysicists
Skills
Libraries/APIs
Node.js, Vue 2, React, jQuery, Vue, REST APIs, OpenAPI, Stripe, API Development, Playwright, TanStack Table, Chart.js, Drizzle, Typeform, React Native for Web, Zod, React Testing Library, Google Calendar API, GraphQL API, Puppeteer, Pandas, Django ORM, Vuex, React Router, AWS Amplify, Claude API, Google APIs, Google Maps API, Leaflet, Stripe Connect, Twilio API, Stripe API, Google Sheets API, Matplotlib, NumPy, SciPy, OpenCV, Inertia
Tools
Claude, Lighthouse, Shadcn, GIS, ChatGPT, Shadcn UI, Vitest, Drizzle ORM, Codex, Bitbucket, TestFlight, TanStack Router, SendGrid, Webpack, Amazon Elastic Container Service (ECS), GitHub Copilot, Pytest, Jupyter, Git, NPM, Gulp, GitHub, MATLAB, Prettier, Sentry, LaunchDarkly, BigQuery, Expo, Figma, Figma to HTML, Claude Code, Zapier, Google Analytics, Celery, Jira, NGINX, Meilisearch, Notion API, Google Sheets, Sketch, Visual Studio, Miva Merchant, Astro, Prisma, PHPStan, Logging, Whisper
Languages
JavaScript, Python, CSS3, HTML5, HTML, CSS, TypeScript, GraphQL, PHP, ECMAScript (ES6), PHP 8, SCSS, Sass, SQL, C#, MDX
Frameworks
Django, Nuxt.js, Next.js, Tailwind CSS, Bootstrap, Express.js, Jest, React Native, OAuth 2, Swagger, JSON Web Tokens (JWT), NestJS, Business Rules Engine, Laravel, Fastify, GeoDjango, Material UI, tRPC, i18next, Alpine.js, Selenium, Vuetify, Redux, Remix, gRPC, Flask, Angular, Filament PHP, Laravel Livewire, Django REST Framework, .NET
Paradigms
Clean Code, Serverless Architecture, REST, Role-based Access Control (RBAC), Microservices, Jamstack, Web Application Architecture, Requirements Analysis, HIPAA Compliance, API Architecture, Mobile Development, Microservices Architecture, Cross-platform, Automation, Responsive, Back-end Architecture, Clean Architecture, B2B, B2C, Stress Testing, Testing, Test-driven Development (TDD), Unit Testing, Search Engine Optimization (SEO), Continuous Deployment, Continuous Delivery (CD), Event-driven Architecture, Refactoring, Mobile UI Design, UX Design, Database Design, UI Design, Web Architecture, DevOps, Fast Healthcare Interoperability Resources (FHIR), HL7 FHIR Standard, Multi-platform Development
Platforms
Firebase, iOS, Android, Netlify, Vercel, Web, AWS Lambda, Docker, Amazon Web Services (AWS), WordPress, Visual Studio Code (VS Code), Google Cloud Platform (GCP), Mixpanel, Sanity Studio, Mobile, Linux, Twilio, PostHog, Webflow, MacOS, DigitalOcean
Storage
PostgreSQL, MySQL, Amazon S3 (AWS S3), Google Cloud Datastore, Redis, Google Cloud, PostGIS, JSON, Databases, SQLite, Cloud Deployment, Elasticsearch, Data Pipelines
Industry Expertise
Healthcare, Project Management
Other
Open Source, Serverless, Georeferencing, Front-end, Full-stack, Back-end, Code Architecture, Firebase Cloud Functions, Deployment, Infrastructure, Incident Handling, Debugging, Legacy Code, Legacy Software, HIPAA, RESTFul APIs, OAuth, OpenTelemetry, EAS, Mobile App Development, Full-stack Development, Web Development, QR Codes, Architecture, Technical Leadership, SDKs, Telemetry, Solution Architecture, Data Analysis, Mobile First, API Integration, User Interface (UI), Documentation, Technical Writing, AI Integration, Software Architecture, Security, Authentication, Push Notifications, App Store, Google Play Store, Dashboards, CSV Import, full stack JavaScript, AI Tools, APIs, Back-end Development, Front-end Development, Event-driven Systems, Middleware, Validation, Regulated Industries, Vite, Minimum Viable Product (MVP), Resend, Page Speed Optimization, Cloud, Figma to React, User Experience (UX), Workflow Automation, Orchestration, Cross-platform App Development, Compliance, Multi-tenant Architecture, Multi-tenant SaaS, CRM, Code Review, Code Auditing, Maps, GPS Tracker, Communication, Data Privacy, Healthcare & Insurance, Dental Services Organizations, Customer Relationship Management (CRM), Cloud Infrastructure, Scalability, Data Integrity, Coding, Web App Development, Spanish, Quality Assurance (QA), SMS, Acceptance Criteria, User Authentication, Performance Optimization, Webhooks, Healthtech, Medical Software, System Architecture, Health, WCAG 2, Web Content Accessibility Guidelines (WCAG), Technical SEO, Infrastructure as Code (IaC), Back-end Performance, Videos, Supabase, TOTP, Uptime Monitoring, Content Delivery Networks (CDN), Geospatial Analytics, Spatial Analysis, Startup Consulting, Technical Project Management, Tools, BetterAuth, Storybook, OXC (Oxlint), Bun, Accessibility, Observability, Consulting, Advisory, Third-party Integration, Enterprise Integration, Tailwind UI, Streaming, Video Streaming, Third-party APIs, Data Visualization, TALL Stack, WebSockets, Startups, Software System Architecture Development, Video Processing, Video APIs, Scheduling, Scheduling Tools, Technical Architecture, Leadership, Distributed Systems, Prompt Engineering, Data Encryption, Responsive UI, Application State Management, Apollo, Apollo Server, Offline Data Synchronization, Authorization, Bug Fixes, Monorepos, Server-side Rendering (SSR), Zustand, Software Engineering, Agentic Coding, SEO Tools, Product Ownership, AI Development, Cloud Storage, Transcoding, EMR, Team Leadership, Scientific Computing, Research, Teamwork, Challenge-based Learning, GPS, PWA, Progressive Web Applications (PWAs), ESLint, eCommerce, Content Management Systems (CMS), Headless CMS, Responsive Design, Cloudflare, Performance, CI/CD Pipelines, Incident Response, Incident Management, Healthcare Software, GitHub Actions, Continuous Monitoring, Geospatial Data, SaaS, Mobile Apps, Mobile App Testing, A/B Testing, Gemini, GitHub Copilot Chat, Core Web Vitals, Cross-browser Compatibility, DNS, MVP Design, Early-stage Startups, Product Management, Artificial Intelligence (AI), Algorithms, Large Language Models (LLMs), OpenAI, Anthropic, Cursor AI, Fractional CTO, AI Agents, CTO, Pinia, Real-time Data, FastAPI, Health Insurance, AI Architecture, Enterprise Integration Patterns (EIP), AI-generated Code, Google Antigravity, Data Science, Messaging, Image Processing, GDPR, Machine Learning, Healthcare IT, Data Analytics, Geofencing, WatermelonDB, Pulumi, Google Calendar, Supabase Auth, Agentic AI, Google Analytics 4 (GA4), Web Scraping, University Teaching, Team Building, Geophysics, Applied Research, English-Spanish Translation, Material Design, eCommerce Platforms, Analytics, Google Cloud Functions, i18n, SSG, Static Site Generators, Content, Website Performance, GitHub Workflows, Google Cloud Tasks, Pub/Sub, OpenID Connect (OIDC), SaloonPHP, Local SEO, Yoast SEO, VPS, Laravel Forge, Electronic Health Records (EHR), Electronic Medical Records (EMR), Migration, Blog Design, Vitess, GCP DevOps, Education Technology (Edtech), Music, Background Jobs, Design
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