fastshop — Fast Mobile-First OpenCart Store
Overview
Independent project: a fast, mobile-first online store on OpenCart 3.0.5 / PHP 8.3, built as an overlay on stock OpenCart — a lean storefront theme, faceted filtering with SEO URLs, a one-page checkout with a Nova Poshta city/branch picker, Redis caching, WebP images and DB indexes — running a 30,000-product catalog and measured against stock OpenCart on the same data.
Result: catalog pages answer in 10 ms instead of 34 ms and search in 5 ms instead of 267 ms; Lighthouse mobile scores 100 with a 19–28 KB page (stock: 272–336 KB, first paint 2.1–2.4 s → 0.6–0.8 s).
The actual hard problem
Stock OpenCart on a large catalog is heavy: a JS/CSS stack shipped on every page, no attribute filters, expensive search, one SEO query per link, sessions in the database, and a multi-step checkout. Making it fast is not one trick but a set of coordinated changes that must survive product edits — the filter index and the page cache have to follow the admin, or the shop shows stale prices.
Architecture
Pages are rendered by controllers hooked in as OpenCart events, so no core file is edited for them. A denormalised facet index (one row per product and category, one per attribute value, covering indexes) serves listings and per-value counts; page data lives in Redis under a version key that admin edits bump. The theme is a single inlined stylesheet plus vanilla JS.
Key Engineering Decisions
| Decision | Why |
|---|---|
| Facet index with counts computed against the other groups | The usual faceting semantics, in ≈9–25 ms for a 3-filter page |
One canonical SEO URL per filter state (/smartfony/f/brand-nordix/price-5000-30000) |
Every state is a crawlable page; other orderings 301 to it |
| Filters update without reload; plain links underneath | Fast for users, still works as ordinary navigation |
| Admin events re-index a product and bump the cache version | Edits show up at once, with no manual cache flush |
| Order created through OpenCart’s own model | It appears in the admin like any other order |
| Keywords for a page’s links fetched in one query | Replaces one seo_url query per link |
Results
Same machine, same 30,000-product data, stock OpenCart 3.0.5.1 vs this set-up:
| Measure | Stock | fastshop |
|---|---|---|
| Catalog page, server time | 34 ms | 10 ms (21 ms with an empty cache) |
| Search | 267 ms | 5 ms |
| Catalog throughput | 160 req/s | 506 req/s |
| Three-condition filter | — | 9 ms |
| Lighthouse mobile | 94–97 | 100 |
| Page weight | 272–336 KB | 19–28 KB |
37 end-to-end checks verify pages, cart, checkout and the admin path — filter counts are compared with an independent SQL count from OpenCart’s own tables.
Growing it into your store
- Your catalog: import with the standard OpenCart tools, then one command builds the filter index.
- Nova Poshta: set
NP_API_KEYfor the live directory. - Payments: orders use OpenCart’s own order model, so a payment extension can take over the payment step.
Source: github.com/valpere/fastshop
Stack
OpenCart 3 · PHP 8.3 · MySQL · Redis · WebP · Docker