BigCommerce Checkout Customization Case Study – Cadencescience.com

How Optimum7 Implemented an Automated, Tax-Compliant Tariff Surcharge in BigCommerce Checkout for Cadence Science

The Business

Cadence Science operates in a pricing environment where change is rarely optional and mistakes are rarely forgiven.

Tariffs and import-related costs shift based on external forces the business doesn’t control, but the impact lands squarely on the checkout experience. Customers need to understand what they’re paying for. Finance teams need charges to reconcile cleanly. Tax systems need the surcharge handled correctly every time.

For Cadence Science, quietly folding tariff costs into product prices wasn’t a long-term answer. It reduced transparency, blurred reporting, and made future adjustments harder to justify. Handling tariffs manually was even worse; it turned checkout into an exception-driven process and introduced unnecessary operational risk.

What they needed was a system-level solution: a way to apply tariffs automatically at checkout, show them clearly to customers, and ensure taxes were calculated correctly, without adding friction to a buying experience customers already trusted.

The Objective

The objective was clear, but precision mattered: automate tariff surcharges inside BigCommerce checkout without breaking tax logic, reporting accuracy, or customer confidence.

From the outset, success was defined by non-negotiables:

Automatic application at checkout, without relying on staff workflows or manual adjustments
Dynamic calculation as a percentage of the product subtotal, ensuring consistent application across orders
Transparent presentation as a separate “TARIFF” line item
Full Avalara compatibility, ensuring the surcharge is handled correctly in tax calculation and reporting
Admin-level control, enabling the internal team to toggle the surcharge and adjust the percentage without code changes
Platform-native alignment, preserving BigCommerce checkout architecture, stability, and long-term maintainability

This wasn’t a temporary fix. The system needs to stay reliable and adjustable as tariff conditions evolve.

Key Business Challenges

1. Platform Constraints

BigCommerce doesn’t offer a native way to introduce a dynamic, taxable surcharge during checkout. Forcing the logic through price changes, discounts, or tax overrides would have created inconsistencies and future maintenance risk.

2. Tax Accuracy and Compliance

If Avalara couldn’t interpret the surcharge correctly, the fallout would show up quickly—in tax calculations, reporting, and reconciliation. Accuracy wasn’t a preference; it was a requirement.

3. Customer Transparency

Tariffs can’t feel like surprise fees. Customers need to see exactly what they’re being charged and why, but the checkout still needs to feel clean, readable, and predictable.

4. Operational Flexibility

Tariff percentages change. Cadence Science needed the ability to respond quickly, without waiting on development cycles or deploying fragile fixes.

The Strategic Challenge

The challenge wasn’t calculating a percentage.

It was deciding where and how that logic should live so it felt native, remained tax-aligned, and stayed manageable over time.

The solution needed to work with BigCommerce and Avalara, not around them, and it needed to give Cadence Science control without introducing fragility at checkout.

Optimum7’s role was to extend checkout behavior carefully, adding capability while protecting stability, reporting integrity, and customer clarity.

The Strategy

Optimum7 approached the problem with a simple guiding principle: solve the tariff issue at the right layer of the platform, and don’t create new problems in the process.

1. Checkout SDK Surcharge Logic

Using the BigCommerce Checkout SDK, Optimum7 implemented real-time logic that evaluates the live cart subtotal, calculates the tariff based on a configurable percentage, and injects it as a distinct “TARIFF” line item in the order summary.

Customers see the charge clearly before placing the order, and product pricing remains clean and unchanged.

2. Avalara-Compatible Tax Handling

The surcharge was structured so Avalara treats it as part of the taxable order total, without introducing separate tax engines, overrides, or manual adjustments.

Taxes are calculated correctly, reporting remains consistent, and the surcharge flows naturally through Cadence Science’s existing compliance setup.

3. Admin Controls for Ongoing Flexibility

To keep the system flexible, Optimum7 implemented internal controls that allowed Cadence Science to enable or disable the surcharge instantly and adjust the percentage without touching a code.

That means the business can respond to tariff changes in real time, without operational bottlenecks.

4. Platform-Native Execution and Long-Term Maintainability

Every decision was made with BigCommerce’s architecture in mind. The solution avoids invasive modifications, stays compatible with checkout standards, and minimizes upgrade risk ensuring the surcharge logic remains stable over time.

Results

The automated tariff surcharge launched cleanly, with full transparency at checkout and no disruption to tax calculation or order processing.

Cadence Science now operates with a surcharge mechanism that behaves consistently across orders, integrates cleanly with Avalara, and can be adjusted internally as requirements change.

1. Key Outcomes

Automated tariff surcharge applied at checkout, consistently and without manual intervention
Dynamic calculation based on product subtotal, ensuring predictable application across all orders
Clear “TARIFF” line item visibility, improving customer understanding and reducing surprise fees
Avalara-compatible tax handling, keeping tax calculation accurate and reporting aligned
Admin-level flexibility, allowing teams to enable, disable, or adjust the tariff percentage without development cycles
Maintainable, platform-aligned implementation built to remain stable through BigCommerce updates

2. Business Impact

Cadence Science can now manage tariff-related costs in a way that is consistent, defensible, and operationally efficient:

Customers see exactly what they are being charged, and why
Taxes remain accurate without manual reconciliation or backend exceptions
Internal teams can respond quickly to changing tariff requirements without waiting on code deployments
Checkout remains clean and predictable, reducing friction and minimizing support inquiries

Most importantly, the business now has a future-ready approach to handling external cost pressure without redesigning product pricing or repeatedly patching checkout behavior.

3. Strategic Outcome

This wasn’t a cosmetic checkout change.

It was a controlled, compliance-focused improvement that protects transparency, tax accuracy, and operational flexibility.

By extending BigCommerce thoughtfully and at the correct architectural layer, Optimum7 delivered a tariff solution that works today and remains dependable as conditions change tomorrow.

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