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Thang Viet To
Senior Backend & Platform Engineer
Summary
Senior Backend & Platform Engineer with 9+ years building production commerce. Specialised in headless Shopify — Storefront API, Admin API and Buy Button SDK — with deep experience in performance, conversion instrumentation and the integration work that keeps large catalogues accurate. Recently delivered a 300,000-product headless bookstore across US and UK storefronts, and hardened a WooCommerce store sustaining 20–30 orders per minute at peak. Languages: English, Vietnamese.
Experience
Simon & Schuster — Senior Shopify / Full Stack Engineer
Feb 2021 – Present · Remote · US & UK storefrontsHeadless Shopify storefronts for a 300,000+ product publishing catalogue across two regions.
- Built the storefront on the Shopify Storefront API with Next.js, replacing theme-bound rendering.
- Ran catalogue and inventory operations through the Admin API at 300k-product scale.
- Kept Shopify checkout via the Buy Button SDK and made hand-off failures diagnosable.
- Instrumented the funnel with GA4, GTM and a Shopify Custom Pixel.
- Covered revenue-critical paths with Cypress E2E in CI.
Shopify · Storefront API · Admin API · Next.js · Cypress · GA4
Cost Price Supplements — Senior Full Stack Engineer
Feb 2021 – Present · RemotePerformance, reliability and integration work on a store peaking at 20–30 orders per minute.
- Profiled and relieved the order-write contention that limited peak throughput.
- Introduced Redis caching and session handling on the hottest paths.
- Built continuous, idempotent warehouse stock reconciliation.
- Shipped Luigi's Box AI search and event-driven marketing automation.
WooCommerce · PHP · Redis · MySQL · Cypress
Order Protection — Senior Full Stack Engineer
Feb 2021 – Present · RemoteShipping-protection app with subscription billing, shipped natively to Shopify, Magento and BigCommerce.
- Designed a platform-agnostic core with thin per-platform adapters.
- Built the Shopify app properly: OAuth, session tokens, webhooks, embedded surfaces.
- Made webhook processing idempotent to eliminate duplicate-charge bugs.
- Handled subscription billing and per-order premium reconciliation.
Shopify App · Node.js · React · PostgreSQL · Payments
Affitor — Senior Full Stack Engineer
Feb 2021 – Present · RemoteAffiliate platform with cross-domain attribution and an idempotent event-processing pipeline.
- Rebuilt attribution to work without third-party cookies.
- Achieved exactly-once accounting on an at-least-once event pipeline.
- Deployed containerised services to AWS ECS with Redis-backed hot lookups.
Node.js · Next.js · AWS ECS · Redis · Docker
ShowdownTV — Full Stack Engineer
Feb 2021 – Present · RemoteLive streaming platform on AWS MediaLive and CloudFront with Redis-backed live state.
- Delivered adaptive-bitrate live video through MediaLive and CloudFront.
- Absorbed start-of-stream traffic spikes through CDN and cached state.
Next.js · Node.js · AWS MediaLive · CloudFront · Redis
Earlier engagements — Full Stack Engineer
Jan 2017 – Feb 2021 · VietnamCommerce and web application work across the JavaScript and PHP ecosystems — the foundation the Shopify specialisation was built on.
- Shipped production commerce features across multiple platforms and teams.
- Moved from general full stack work into deep commerce-platform specialisation.
JavaScript · React · Node.js · PHP · MySQL
Selected projects
Affitor — Distributed event processing · Affiliate platform
Exactly-once payout accounting on an at-least-once event pipeline, after third-party cookies died.
Order Protection — Multi-tenant SaaS · Subscription billing
A multi-tenant shipping-protection SaaS with subscription billing, installed natively across three commerce platforms from one core.
Simon & Schuster — Headless commerce · Publishing
A 300,000-product headless bookstore cut over live, across two regions, on one commerce backend.
Cost Price Supplements — Performance & reliability · High-traffic retail
Found the real bottleneck in the order-write path — not the catalogue cache everyone assumed.
ShowdownTV — Live video · AWS media services
Absorbing a start-of-stream traffic step, where viewer scale is a CDN problem rather than an origin one.
Technical skills
Open to
Senior Backend Engineer · Platform Engineer · Senior Full Stack Engineer · Staff Engineer