Selected work / 01
Athlean-X
Custom commerce. Real-world scale.
100k+
Daily visitors served
Timothy CevallosTaking new projects
Senior full-stack developer
I build websites, commerce platforms and web apps — with nine years of experience at Athlean-X, Nielsen and independent client projects.
Hiring for your team? Explore my experienceWorked for
- Nielsen
- Athlean-X
- Samtek
- Antamba
- Bikerevier
- Island Painting
01 — How I can help3
Most projects begin in one of three places: a platform you have outgrown, a site that no longer works hard enough, or nothing live yet. Each page covers what is included, how the work runs, and the questions clients ask first.
02 — Selected work
Commerce at scale. Tools that give editors their time back. A closer look at what I built and why it mattered.
Bikerevier
WooCommerce redesign for a Swiss bike shop
A mobile-first redesign of a Swiss bicycle shop’s WooCommerce store lifted checkout conversion by 25%.
Read the case studySmall business builds
03
Websites2021
Island Painting
Designed and developed a WordPress-based promotional site for a local business, optimizing performance and tracking for lead generation.
- WordPress
- JavaScript
- PHP
- HTML
- +7
04
Websites2022
Antamba
Built a fully custom WooCommerce e-commerce site for a client, handling design, functionality, and optimization from end to end. Integrated with Google and Meta for tracking and advertising.
- WordPress
- WooCommerce
- JavaScript
- PHP
- +9
How we work together
You work directly with the person building it. Clear decisions, visible progress, and a handover you can use.
Understand
We define the problem, the people using the product, and what success looks like. Scope and priorities come before code.
Build
I turn the plan into working software, share progress, and make room for feedback. Performance and accessibility are part of the build.
Launch
We check the details, prepare the release, and hand over the code and documentation so you can move forward with confidence.
03 — The person behind the work
I’m a self-taught full-stack developer who has spent nine years inside production systems: a direct-to-consumer business serving 100k+ visitors a day, an enterprise data platform at Nielsen, and a government content migration on a deadline. I know what breaks under real traffic, and I build so it doesn’t.
Working with me is simple. You get a straight answer on scope and price before anything starts, plain-language updates while it’s being built, and full ownership of the code when it ships. Away from the keyboard I cook, garden and train.
01
Frontend
React · Next.js · TypeScript · Tailwind
02
Backend
PHP · Laravel · NestJS · FastAPI
03
Data
PostgreSQL · Redis · pgvector · Qdrant
04
AI
RAG pipelines · vector search · multi-LLM
04 — Toolkit74 tools
From building scalable web applications to implementing AI-powered solutions, here's my technical toolkit.
9years
PHP
Server-side scripting
9years
WordPress
CMS & custom development
5years
React
Component-based UI library
5years
Laravel
PHP web framework
The full stack
Frontend
15- JavaScript
- TypeScript
- React
- Next.js
- HTML5
- CSS3
- Tailwind CSS
- SCSS
- Alpine.js
- jQuery
- Bootstrap
- Responsive Design
- WCAG/Accessibility
- Chart.js
- Webpack
Backend
11- PHP
- Laravel
- Blade Templates
- Composer
- Node.js
- NestJS
- Python
- FastAPI
- REST APIs
- GraphQL
- Zend Framework
CMS & e-commerce
8- WordPress
- WooCommerce
- Gutenberg Blocks
- Advanced Custom Fields
- WP-CLI
- Elementor
- Contentful
- Headless CMS
Databases
8- MySQL
- PostgreSQL
- Redis
- pgvector
- Qdrant
- Drizzle ORM
- Prisma
- Query Optimization
AI & ML
8- OpenAI API
- Claude API
- RAG Pipelines
- LangChain
- Vector Search
- Embeddings
- Prompt Engineering
- Multi-LLM Routing
DevOps & hosting
8- Git
- Docker
- Vercel
- AWS
- CI/CD
- Linux
- cPanel
- SVN
Integrations
8- Stripe
- Stripe Connect
- Clerk Auth
- Auth.js
- SendGrid
- Google APIs
- Meta APIs
- Webhooks
Performance & SEO
8- Technical SEO
- Local SEO
- Core Web Vitals
- Structured Data
- Google Analytics
- Google Search Console
- Progressive Web Apps
- Site Migrations
05 — Experience
Nine years across enterprise data platforms, a direct-to-consumer business at scale, and independent client work.
2026 — Present
Senior Web Developer (Contract)
Samtek
Migrating structured content from Contentful into WordPress for a confidential U.S. government agency on an accelerated delivery schedule, with no loss of URLs, accessibility compliance, or editorial workflow.
- 01Built repeatable migration tooling that maps Contentful content models to WordPress post types, ACF fields, and Gutenberg blocks with automated validation
- 02Preserved URL structure, redirects, metadata, and Section 508 / WCAG 2.1 AA compliance on every migrated page
- 03Coordinated phased cutovers with content and QA teams on a compressed, high-visibility timeline
WordPress · PHP · Contentful · TypeScript · Node.js · WP-CLI · REST APIs · ACF · Gutenberg
2024 — Present
Freelance Full-Stack Developer
Self-Employed
Building production-grade SaaS platforms, AI-powered applications, and analytics dashboards for clients using modern tech stacks including Next.js, NestJS, and AI/LLM integrations.
- 01Built multi-tenant SaaS invoicing platform with Stripe Connect
- 02Architected RAG-powered AI support system with multi-LLM support
- 03Developed real-time analytics dashboard for parking operations
Next.js · React · TypeScript · NestJS · PostgreSQL · Stripe · AI/LLMs · FastAPI
2022 — 2024
Senior Web Developer
Nielsen
Led frontend development for enterprise data visualization platform, creating dynamic Gutenberg blocks and improving performance.
- 01Built custom Gutenberg blocks for data visualization
- 02Improved site performance and accessibility scores
- 03Collaborated with product teams on feature delivery
WordPress · PHP · Alpine.js · Tailwind CSS · Chart.js · Gutenberg
2017 — 2022
Full Stack Developer
Athlean-X
Managed full-stack development of high-traffic e-commerce and content platforms serving 100k+ daily visitors.
- 01Built scalable Laravel e-commerce systems
- 02Maintained WordPress blog with custom features
- 03Developed progressive web application portal
Laravel · PHP · WordPress · JavaScript · MySQL · Zend Framework
- Years shipping
- 9+
- Daily visitors served
- 100k+
- Projects delivered
- 50+
Tell me what’s broken or what you need built. You’ll hear back within one business day with a straight answer on scope, timeline and cost.
Tell me what you have in mind06 — Contact
Tell me what’s broken or what you need built. You’ll hear back within one business day with a straight answer on scope, timeline and cost.
contact@cevallossystems.comReplies within one business day