Auditing the Add-A-Line flow at T-Mobile for Business — finding the friction points in a Fortune-100 SMB checkout.

The engagement was not a redesign — it was a structured audit of an existing high-volume flow on a Fortune-100 carrier's shop. The Un-carrier's SMB segment was rapidly expanding and the Add-A-Line PDP was the load-bearing surface for that growth: every new business line a customer provisioned passed through this page, the plan picker, and the SIM-activation form.

Findings were documented against process-compliance and UX heuristics, then presented to internal leadership. The deliverable was not a Figma file — it was a defensible written record that the platform team and the SMB business owners could prioritise against. For a Fortune-100 carrier, that defensibility is the point.

The buyer here is not the consumer customer who walks into a T-Mobile retail store. The buyer is an SMB IT lead, an office manager, or an owner-operator provisioning lines for employees — someone making a multi-line commercial decision under time pressure, often on a desk without a dedicated procurement workflow.

These buyers compare three Business Unlimited tiers — Advanced, Ultimate, and Select — at price points from $65/mo to $90/mo per line. They are also adding services (data add-ons, international features, other extensions) and reading the fine print: hotspot allowances, video-streaming quality, congestion-prioritisation language, 5G coverage notes. The PDP has to do the work that an enterprise account executive would do in a higher-touch sale.

Two friction patterns kept surfacing during the audit: the plan-comparison surface buried the differences between tiers behind "View plan details" links rather than showing the trade-offs at the moment of decision, and the additional-services panel mixed plan-included features with paid add-ons in a way that made the line-item math hard to verify against the summary card on the right.

I sat between the platform's product owners, the design organisation, and the operations group that owned the post-purchase activation pipeline. Each of them had a stake in the same surface: product owned the conversion narrative, design owned the brand expression and the Un-carrier voice, operations owned what happened after the order hit "Add to cart."

My specific responsibilities were the end-to-end process audit of the Add-A-Line flow, the UX audit of the PDP and the SIM-activation form, the compliance review against internal digital-business-process standards, and the leadership presentation that translated findings into roadmap-prioritisable items.

I mapped the Add-A-Line flow as a digital business process — every step from catalog entry through SIM activation, plan selection, additional-services configuration, summary review, and add-to-cart. Each step was annotated against process-compliance criteria: input validation, error recovery, state preservation across navigation, and the post-purchase handoff to the activation pipeline.

The output was a process map with two annotation layers: one for compliance gaps (places where the flow violated internal digital-business-process standards) and one for UX-heuristic violations (places where the surface itself created friction independent of the underlying process).

The PDP itself went through a heuristic review against Nielsen's usability heuristics, with extra weight on three categories the SMB buyer relied on: visibility of system status (the sticky summary card), match between system and the real world (plan-comparison language and Business Unlimited trade-off framing), and consistency and standards (alignment between the shop, the activation form, and the brand surface treatment per the T-Mobile brand guidelines — TeleNeo, Magenta hero, Un-carrier voice).

The plan picker, the additional-services tabbed panel, and the sticky summary card were each documented as separate audit objects with their own findings and recommendations. The summary card was the highest-leverage object: it was the surface where the SMB buyer verified the line-item math before committing.

I presented the audit to internal platform and SMB-business leadership. The presentation was structured to be roadmap-actionable — every finding was tagged with severity, scope of fix, and which team owned the remediation. The format was deliberately not a slide deck of screenshots; it was a written audit document with a slide presentation overlay, designed to leave behind a defensible artifact after the room emptied.

Recommendations fed roadmap prioritisation for the following quarters. The audit was the input; the platform team owned the output.