Portmux is a Shopify to BigCommerce migration service that moves your full catalog, customer base, order history, and SEO redirect map into BigCommerce, with the URL strategy in place to keep your organic traffic alive on day one.
The data side of Shopify-to-BigCommerce is straightforward. The risk is SEO. Shopify and BigCommerce structure their URLs differently (/products/handle vs /products/category/product), and a sloppy migration kills 30–50% of organic traffic in the first month. We build the redirect map first, validate it against Search Console, and only then move the catalog.
Product records with title, description (HTML preserved), brand, SKU, MPN, GTIN, weight, and inventory tracking.
Shopify variants (up to 100 per product, 3 option types) mapped to BigCommerce Product Options and Variants with SKU-level inventory.
Smart and Manual Collections converted to BigCommerce Categories; Collection rules become Category product assignments.
All product images downloaded from Shopify CDN and re-uploaded to BigCommerce with alt text and sort order preserved.
Customer records with addresses, accepts marketing flag, customer groups, and order history association.
Full order history with line items, applied discounts, taxes, shipping, fulfillments, and refund history.
Active Shopify Discount Codes and Automatic Discounts converted to BigCommerce Coupon Codes and Cart-Level Promotions.
CMS Pages and Blog Articles migrated to BigCommerce Web Pages and Blog Posts with author and publish date preserved.
Shopify Online Store navigation menus rebuilt as BigCommerce Navigation Menus with the same hierarchy.
Shopify URL Redirects + every product/collection/blog URL mapped to its new BigCommerce path as 301 redirects from day one.
Product, customer, and order metafields exported and stored as BigCommerce custom fields or product custom_fields.
Outstanding Gift Card balances exported with original codes; BigCommerce Gift Certificates created with the same redemption codes.
Shopify Admin API and Storefront API index the full catalog, customer base, order history, and Online Store content. We pull the current URL map (every live product, collection, blog, and page URL) so we know exactly what redirects need to exist on cutover day.
Catalog mapping is straightforward (Products, Variants, Categories). The harder mapping is Shopify Apps that don't have BigCommerce equivalents, subscriptions, reviews, loyalty programs, we identify each one and either find a BigCommerce app, build a custom integration, or document a manual workflow.
BigCommerce staging store loaded with full catalog and order history. Your team QAs the storefront, checkout, and tax rules. On cutover day, DNS is flipped to BigCommerce and a full redirect map (typically 5,000–50,000 URL redirects) is pushed via the BigCommerce Redirects API. Search Console gets the new sitemap immediately.
Every migration has its own gotchas. Here's what we plan for on this specific path.
This is the migration. Shopify products at /products/{handle} need 301 redirects to BigCommerce URLs at /{category}/{product-name}. We build a URL-by-URL redirect spreadsheet, validate against your top 1,000 organic landing pages, and push redirects on cutover. Lose this and you lose organic traffic for months.
Subscriptions (ReCharge, Shopify Subscriptions), reviews (Yotpo, Judge.me), loyalty (Smile, LoyaltyLion), and post-purchase upsell apps often need replacement. Some have BigCommerce versions, some need custom integration, some aren't worth replacing. We audit each app and recommend.
Shopify allows 100 variants and 3 option types per product. BigCommerce allows more option types but enforces variant SKU rules differently. Products with rule-based variants (e.g. Size + Color + Material with conditional availability) need careful re-modeling so the storefront still shows the right combinations.
Shopify Tax (US automatic tax) doesn't have a 1:1 BigCommerce equivalent. BigCommerce uses Avalara, TaxJar, or manual tax rules. We re-derive your tax setup from Shopify rates and either configure native BigCommerce tax classes or wire up a third-party tax provider during the rehearsal phase.
Single-system migrations like Shopify to BigCommerce run as Track A engagements: one source, one destination, up to 1M records, 4–6 weeks. Final price depends on object volume, custom field count, and integrations, scoped on a 20-minute call before any commitment. See full pricing →
Tell us what's in the source, where it's going, SaaS or custom, and when you need to be live. You'll walk away with a scoped quote, a named engineer, and a go-live date.