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Rethinking second-hand shopping.

Creating a mobile friendly marketplace to transform the way second-hand clothes are sold and purchased in LatAm.

Project snapshot

Company: Polymath Ventures (Company Builder)

Role: Lead Service & Business Designer

Duration: 9 months

Focus: Buyer + Seller experience, marketplace trust, onboarding, retention.

Methods: In-depth interviews, synthesis, archetypes, wireframes, prototyping, MVP build, pitch decks, iterative testing.

Impact: Validated marketplace model, onboarded early sellers, launched MVP, shaped retention flows + investor alignment.

What I did:

Led all initial research: crafted interview guides, conducted interviews with buyers and sellers, and synthesized insights.
Created seller and buyer archetypes, mapped journeys, surfaced friction in both sides of the market.
Designed wireframes and clickable prototypes, ran usability tests and iterated.
Built the MVP on Shopify, onboarding sellers and working with engineers to refine for launch and retention.
Developed weekly pitch decks and investor updates to drive alignment with C-Suite and stakeholders.

Setting the stage for marketplace validation.

Ropstar's first wireframes and mockups for testing.

Context

In Latin America, many second-hand platforms exist, but few are trustworthy, mobile-first, or designed for localized seller needs.

The key challenge: how to create a marketplace where buyers feel confident and sellers can scale safely.

Sellers struggled with pricing, logistics, and presentation.
Buyers worried about quality, authenticity, and trust.
There was a lack of a unified platform built for the cultural nuances of Latin American second-hand commerce.

Leadership needed a validated concept and early traction to justify further investment.

My contribution

My Role

👉 I led the entire product discovery and design stream, from research through MVP delivery and iteration.

👉 I served as the bridge between engineering, and business, translating insights into actionable decisions.

What I did

Interviewed 20+ sellers and 20+ buyers across Colombia & Mexico, uncovering core motivations, obstacles, and trust dynamics.
Synthesized interviews into archetypes (e.g. “casual seller,” “power seller”, “value buyer”) to guide feature priorities.
Mapped dual-side journeys, surfacing critical moments of hesitation and drop-off for both sellers and buyers.
Designed wireframes and high-fidelity prototypes, and ran usability tests to refine flows for listing, browsing, purchase, and reviews.
Built a working MVP on Shopify, launched with a pilot cohort of early sellers, and monitored retention and usability metrics.
Created weekly pitch decks for investors and C-Suite, using research and metrics to justify next steps.
Partnered with engineers post-launch to refine the platform UX, retention loops, and feature backlog based on user feedback.

Outcomes

✅ Launched a functional marketplace MVP with transactable flows and seller onboarding.

✅ Onboarded early sellers and collected buyer feedback to calibrate core features.

✅ Used research-backed prototypes and data to secure investor alignment for further development.

✅ Activated retention strategies and UX improvements with engineering to reduce churn.

Seller Archetype Analysis and Desktop Research.

Process

01/

The challenge

I kicked off with qualitative interviews and contextual observations to understand both sides of the marketplace — motivations, fears, and unmet expectations.

We surfaced insights about trust, quality, and user psychology that shaped feature hypotheses.

02/

The Research

Synthesis & Ideation

Using affinity clustering and user archetyping, I distilled patterns and mapped buyer + seller journeys.
Key friction points guided ideation sessions, where design proposals were sketched and prioritized.

Prototyping & Validation

I built wireframes and prototypes, ran usability tests, iterated on flows, and refined based on real feedback.
Before full build, I ran validation checks with mock data and test users to reduce risk.

03/

MVP and launch

We built the MVP on Shopify to get to market quickly. I led seller onboarding, collected behavioral data, and tracked retention.
Weekly decks updated stakeholders on learnings, challenges, and roadmap adjustments.
Collaboration with engineering ensured UX refinements post-launch.

"I dropped off because I felt lost in the process".

7/20 users said they lost tracking mid-bootcamp.”

Learnings for next time

My journey maps weren't the prettiest. But perfect journey maps aren’t what drives impact. Turning journey maps into living assets was more impactful than perfecting every detail.