KottoLink is a mail-in buyback mobile app that lets you sell antiques and curios by “just taking a photo from home.” With no store visits or paper mailing, everything from listing to payment is completed within the app.
Listing experience · appraisal transparency · identity verification/payment · progress visibility ─ the story of launching a new platform, built in-house from scratch in 8 months, satisfying all four axes essential to mail-in buyback at once.
A reuse business that buys items nationwide, focused on antiques, curios, and tea-ceremony utensils. Until now its buyback was mostly face-to-face — in-store or on-site — missing customers outside its catchment area and those who found dropping items off a burden.
So we made “just take a photo to get an appraisal” mail-in buyback a new pillar, launching KottoLink — a new platform that completes listing, appraisal, identity verification, payment, and progress tracking entirely within the app.
None of these were questions of technology choice, but business requirements tied directly to listing volume, customer satisfaction, identity-verification safety, and operational efficiency. Building anew from scratch demanded a design that satisfied them all at once.
If in-store drop-off and packing effort remain — missing sellers who hesitate to list — and buyback counts stall.
If shipping is asked for while the offer stays hidden — anxiety drives more drop-offs — and conversion rates fall.
If identity verification and account registration rely on postal mail — payment takes several days — and the experience suffers.
If the design for conveying appraisal, shipping, and payment status is wrong — inquiries pile up — and operating costs swell.
We built the entire experience from listing to payment in-house from scratch, split into four domains. For each domain's design challenge, we combined mobile app, cloud, and notifications to solve it.
React NativeReact Navigation
i18next
Laravel
Laravel Passport (OAuth2)
AWS S3
Firebase Cloud MessagingOneSignalThis foundation produces not technical metrics but continuous business outcomes: more listings, higher conversion rates, operational efficiency, and a wider market area.
List with photos alone, no store visit needed — capturing the customers previously missed.
With photo-first appraisal and chat, sellers can accept only once satisfied with the offer.
Centralized transaction-status management and automated notifications keep staff from being buried in inquiries.
Supporting mail-in buyback from anywhere, maximizing new customer segments and transaction volume.