Designing a two-sided marketplace for on-demand mobile carwashes

A first-of-its-kind app connecting busy car owners with independent mobile carwash businesses, built around a simple idea: help small businesses grow until they don't need us anymore.

Two angled smartphone screens showing a car care app named Sparkling! with login fields and a home screen featuring search, flash deals, and profiles of nearby users.

Signup/Sign-In and dashboard Screens

Role

UX Designer

company

Student project

status

Concept

Context

SPARKLING! started as a certificate course project and grew into a personal concept worth pursuing. The idea came from a real moment, my partner needed a carwash while I was ordering DoorDash. The parallel was obvious: if food delivery could come to you, why couldn't a carwash?

The problem

Getting a car washed is inconvenient for people stuck in meetings, busy with work, or just short on time. On the other side, small mobile carwash businesses struggle to get discovered and often have trouble collecting payment reliably after a job. SPARKLING addresses both sides; convenience for the customer, visibility and secure payments for the sparkler.

A sequence of eight mobile app screens showing steps to set a car detailing appointment, select date and time, choose a detailer, pick services and protection options, enter payment details, apply promo code, and confirm the appointment.

Order and checkout flow

What I did

Designed a homepage that communicates the concept instantly, no explanation needed.
Built a multi-step ordering flow balancing simplicity for the customer with enough detail for the sparkler to do their job.
Designed signup and signin pages with Google, Apple, and Facebook authentication to reduce friction at first use.
Created confirmation pages that set clear expectations on both sides.
Wrestled with the checkout process to make payment feel seamless without losing trust.

What I'd do next

- Add a two-way ratings system, customers rate sparklers, but sparklers rate customers too. Borrowed from the DoorDash experience, this levels the playing field and protects small business owners from bad actors

- Design a sparkler-side profile page so small businesses can build reputation and get discovered organically

- Add a live tracking screen so customers know exactly when to expect their sparkler

- Explore a tipping prompt designed to feel natural, not guilt-driven

UX research

Interaction design

User flows

Rapid prototyping

Competitive analysis