The opportunity

Arity’s Routely SDK is the engine behind some of the most-used safe-driving apps in the U.S. — but most of its early embedded-product work lived in the auto-insurance space, where the user already expects telematics in exchange for a discount.

OfferUp is a different animal: a 20M+ monthly-active-user marketplace where buyers and sellers meet for in-person, often vehicle-based, transactions. The opportunity was to surface a driving experience that:

• Felt native to a marketplace app, not bolted on
• Was honest about what was being measured and why
• Could opt-in without scaring away casual users
• Performed identically across iOS and Android in the first release

I led UX for Arity’s side of the partnership — owning the in-app driving experience, the onboarding flow, and the design-system handoff to OfferUp’s mobile team.

What I owned

• Discovery and joint product workshops with OfferUp’s product, design, and engineering leads
• End-to-end UX for the driving experience — first run, trip detection, score surfacing, history, and settings
• Onboarding and consent flow tuned for a non-insurance audience
• A focused subset of Arity’s mobile pattern library, shipped as a partner-ready spec
• Continuous QA in collaboration with the App Collective engineering team

Process

1. Frame the partner’s user, not ours

Arity’s existing patterns assumed an insurance-motivated user. I ran lightweight interviews with OfferUp-style buyers and sellers — people whose mental model of “the app” was find a couch and drive across town, not earn a safe-driver discount.

The reframing was simple but consequential: driving features had to earn their place inside a transactional context. That shaped every screen that followed.

2. Design the opt-in like a feature, not a disclosure

The single biggest risk to the partnership was a low opt-in rate. I designed a multi-step onboarding that:

• Led with the user benefit (safer trips, recap of recent driving) before asking for sensor permissions
• Sequenced permissions in the order iOS and Android grant them most cleanly
• Used calm, evidence-based language sourced from Arity’s brand voice library
• Gave users a real “not now” path — measured separately so we could learn from declines

3. Ship parity on iOS and Android

Working closely with the App Collective engineering team — Michael Laverty’s group — I kept Figma, redlines, and prototype updates in one source-of-truth file with naming conventions matched to engineering’s component tree. That tight loop is what Michael’s quote above is about: fast handoffs, clear updates, and no surprises in QA.

Outcomes

• Driving experience shipped on iOS and Android at parity in the first release window
• Reached 20M+ monthly active users through the OfferUp install base
• The partnership now serves as Arity’s anchor reference in pitches to the next wave of marketplace and mobility partners
• Internal partnership-design playbook documented from this engagement (now reused across new deals)

Reflection

The hardest UX problem here wasn’t visual — it was emotional. Buyers and sellers don’t open OfferUp expecting to think about driving safety, and a single tone-deaf permissions screen could have killed adoption.

What worked was holding the bar on calm, honest, evidence-based copy and making the engineering loop so frictionless that we could iterate after launch instead of treating the first release as the last word.

Note: visuals and screen flows for this case study are protected under the OfferUp partnership agreement. The full unredacted walkthrough is available on request — reach out via the contact page.