Custom code gave you control. But the maintenance cost compounds every quarter.
An honest cost analysis of custom-built delivery date logic versus Flare. When custom code was the right call, what it really costs to maintain, and where Flare gives you the same rule depth without the dev dependency. Including when custom is still the better choice.
When custom code was the right call.
If we pretended custom builds are always wrong, you'd stop reading. They're not. Here's why building made sense — and might still for some teams.
Full control over every edge case
When you built custom, no app could handle your specific combination of postcode zones, carrier rules and product lead times. Custom code gave you exactly what you needed — and nothing you didn't.
No vendor dependency
Your delivery logic lived in your codebase, deployed on your schedule. No app store reviews, no third-party outages, no features gated behind pricing tiers. Your team owned it end to end.
Built for your exact workflow
Custom code could integrate with your specific 3PL, match your fulfilment team's exact process, and adapt to edge cases no product manager at an app company had ever seen.
What custom delivery logic actually costs to maintain.
The build was a one-time investment. The maintenance compounds. Four costs that most teams underestimate — because they're spread across sprints, not invoiced in one line.
Every rule change needs a developer
A new postcode zone, a shifted cut-off time, a seasonal blocked date — each change requires a dev ticket, a code review, a deployment. Operations teams can't self-serve. The simplest rule change takes days, not minutes.
Shopify updates break it
Shopify ships platform updates continuously. Each one is a risk to custom checkout code — theme changes, API deprecations, checkout flow updates. Your team has to monitor, test and patch. The alternative is discovering it's broken when customers do.
Peak traffic exposes the cracks
Custom delivery logic that works at normal volume can fail under Black Friday, Valentine's Day or holiday peaks. A slow or broken checkout at peak traffic doesn't just create support tickets — it loses sales at the moment your store has the most customers ready to buy. Load testing, caching, error handling — the infrastructure work that prevents this is ongoing engineering, not a one-time build.
Every new use case is a new build project
Carrier integration, subscription logic, a new 3PL data format, a lead time rule that didn't exist last quarter — each one is a new build project with scoping, development and testing. Meanwhile, every rule gap in production produces an order that someone on your ops team has to manually fix with the customer. The build cost was one-time. The cost of keeping it complete never stops.
The same rule depth — accurate, fast, and nobody has to worry about it.
Four operational wins, mapped one-for-one to the custom code costs above. 700+ Shopify brands, $10M+ in orders every month, 99.8% accuracy, 195ms average API response.
Operations teams control the rules
Postcode zones, product lead times, method-specific windows, cut-offs, blocked dates, capacity limits — all configurable without a developer. Rule changes take minutes, not sprint cycles. Your ops team self-serves.
Checkout performance that directly affects conversion
Flare runs as a native Shopify checkout extension — 195ms average API response, zero lines of theme code, built on Checkout Extensibility and Functions APIs. 195ms isn't a technical stat — it's a revenue stat. Every millisecond of checkout delay increases abandoned carts. Faster checkout means fewer customers drop off before payment and more completed sales. When Shopify updates, Flare updates with it. No patching, no monitoring, no lost sales from a broken checkout.
Tested at scale — every week
345,000+ checkout requests in the last 7 days. 700+ brands processing $10M+ in orders every month. p95 at 567ms. Flare's infrastructure handles peak volume because it's always running at peak volume — across hundreds of stores simultaneously.
It just works — accurately, at scale, all the time
Carrier integrations, subscription logic, new 3PL formats, lead time rules that didn't exist last quarter — Flare ships these as product updates, not as your engineering team's next sprint. The person who owns delivery in your business gets something that works accurately, performs at checkout speed, and doesn't need constant fixing or improving. Starting at $39/month.
Flare vs Custom Code — nine dimensions.
Operational rows only. Custom code can technically do anything — the question is what it costs to build and maintain each capability.
| Capability | Flare | Custom Code |
|---|---|---|
| Visual calendar at checkout | ● | Dev build |
| Postcode / ZIP zone rules | ● | Dev build |
| Shipping rate logic | ● | Dev build |
| Rule changes without a developer | ● | ○ |
| Order tagging / 3PL automation | ● | Dev build |
| Checkout validation (catches invalid orders) | ● | Dev build |
| Survives Shopify platform updates | ● | ○ |
| Peak-traffic tested infrastructure | ● | Varies |
| Ongoing feature development | ● | ○ |
From custom code and other platforms to Flare.
Verbatim from the Shopify App Store. We didn't write any of this.
"We recently transitioned from Magento to Shopify, and Flare offered the complex functionality our customers need without us having to upgrade to Shopify Plus. An intuitive App, supported by excellent customer service from Daniel & Alex. Many thanks!"
"The nice thing about Flare is that we don't have to make a custom integration with our 3PL, and it is easy to set up. I spent a very long time looking for a solution in Shopify because we had this for our WordPress website. Solution found with Flare."
"The genuine edge cases are rare and specific — but they exist."
A proprietary carrier API that doesn't exist on the market. Delivery logic that's inseparable from a bespoke ERP system your team built from scratch. Multi-platform shipping orchestration across non-Shopify systems. These are real scenarios — but for the vast majority of Shopify merchants, they don't apply. If you're running postcode zones, product lead times, carrier rules, cut-offs and 3PL integrations on Shopify, Flare handles that. Most merchants who built custom did it because no app handled their combination of rules at the time. That's changed. The decision to build was right then — the question worth asking now is whether it's still right.
Accurate dates, fast checkout, zero maintenance. See if Flare fits.
Bring us your current rules — postcodes, lead times, methods, cut-offs, carrier logic. If Flare can match them with better checkout performance and no dev dependency, we'll prove it in a 15-minute call. If it can't, we'll tell you.
7-day free trial · Assisted setup included