The Question Every Growing E-Commerce CTO Eventually Faces
At some point in the lifecycle of any subscription e-commerce business, the architecture review becomes unavoidable. The original platform — whether Shopify, WooCommerce, or a custom build from the early days — starts showing structural limits. Features take longer. Workarounds accumulate. Engineers start dreading certain parts of the codebase.
The question that follows is almost always framed incorrectly: "Should we rebuild, or stick with what we have?" The better question is: "What is the right architecture for the business we are now, and the business we plan to be?"
This post documents how I've approached that question — including a detailed cost comparison that often surprises people.
Why Standard Retail E-Commerce Platforms Don't Fit Subscription Models
The fundamental problem with retail-focused platforms (Shopify being the dominant example) for subscription businesses is that the entire platform is designed around a different mental model.
Retail e-commerce is transaction-first: customer browses, selects, pays, done. The relationship ends at the confirmation email.
Subscription e-commerce is relationship-first: the customer signs up, and then you manage an ongoing, evolving relationship across dozens of interactions — skips, pauses, swaps, gift redemptions, dunning, reactivations, plan changes. The subscription lifecycle is the product.
This manifests in concrete capability gaps:
| Subscription Requirement | Platform Limitation | Consequence |
| --- | --- | --- |
| Customer-based delivery scheduling | Not native — custom app required | Custom dev cost on top of platform fees |
| Skip / pause / swap / opt-in logic | Third-party plugins with limited flexibility | Plugin constraints, workarounds, multiple vendor dependencies |
| Zone-based routing and fulfilment | No concept exists natively | Entire workflow needs a custom app |
| B2B portal with custom pricing | Separate solution required | Additional SaaS cost and integration complexity |
| Weekly product cycle management | Static catalogue model | Misalignment with buying/operations workflows |
The Cost Analysis
In 2023, I ran a rigorous cost comparison for a subscription business doing approximately £3M monthly revenue. The comparison was between a Shopify Plus + plugin stack and a hybrid bespoke solution (custom core + best-in-class SaaS for commodity capabilities).
| Cost Component | Shopify + Plugins | Hybrid Bespoke |
| --- | --- | --- |
| Platform / Infrastructure | £1,600/mo | £2,000/mo (AWS) |
| Subscription management | £1,600/mo (Recharge) | Included in custom build |
| CMS / landing pages | £160/mo | £350/mo (Builder.io) |
| Fulfilment management | £500/mo | Custom (included) |
| A/B Testing | £400/mo | Statsig (included) |
| Referral platform | £1,500/mo | Custom / included |
| Cancellation flow | £1,500/mo | Custom / included |
| Transaction fees (0.5%) | £46,000/mo | £0 |
| Staff costs | £30,000/mo | £48,839/mo |
| TOTAL | £83,630/month | £61,739/month |
Annual saving in favour of bespoke: ~£262,000.
The staff cost differential reflects the engineering capacity needed to build and maintain what the plugins would otherwise provide. The platform + transaction fee savings more than offset this — and critically, the transaction fee saving scales with revenue. At higher revenue, the advantage grows dramatically.
The "Hybrid" Framing Is Important
The word "bespoke" triggers alarm in experienced CTOs — and rightly so. Fully bespoke systems are expensive, slow to build, and accumulate debt. The key is the hybrid model: build only what differentiates you, buy everything that doesn't.
| Capability | Approach | Rationale |
| --- | --- | --- |
| Payment processing | Stripe + Braintree (SaaS) | Best-in-class, PCI-compliant — no competitive advantage in building this |
| Subscription / delivery logic | Custom | Core business logic — must be owned and controlled |
| CMS / landing pages | Builder.io (SaaS) | Marketing must move without engineers in the critical path |
| Email / SMS | Brevo (SaaS) | Commodity communications |
| Feature flags (frontend) | Statsig (SaaS) | Built-in statistical significance for A/B tests |
| Customer support | Dixa (SaaS) | Specialist tooling, integrated via API |
| Admin / ops tooling | Custom | Unique operational workflows requiring bespoke tooling |
The result is a system where engineering effort is concentrated on genuinely differentiated capabilities, while commodity capabilities are delegated to vendors who do them better.
When Platform Wins
To be fair: for businesses where the subscription model is simple (basic recurring billing, standard catalogue, no fulfilment complexity), Recharge on Shopify is a perfectly viable choice. If your model is "ship the same box every month", the platform economics look different.
The decision framework:
- 1.Map your business model's capabilities that are not standard e-commerce
- 2.For each, evaluate whether a platform plugin can meet your requirements without workarounds
- 3.Build a genuine cost model including transaction fees — these are usually underestimated
- 4.Make the decision on data, not instinct
The "just use Shopify" instinct is correct for many businesses. For subscription businesses with genuine operational complexity, it's usually wrong — and the numbers show it.