Feirajá - UX Case Study

The Problem

How do you digitize the experience of a traditional street market without destroying what makes it special?

I grew up around one of the biggest open-air markets in Amargosa, Bahia. My grandfather was a farmer with his own stall — every weekend was a ritual of fresh produce, familiar faces, and the kind of trust you only build over years. When I moved to a city, I kept asking myself: why can't I have that freshness delivered to my door?

That question became Feirajá.

Street markets are one of Brazil's most deeply rooted food systems — yet they remain almost entirely untouched by digital products at scale. The opportunity wasn't just a business one. It was cultural, social, and deeply human.

Starting with desk research and a CSD Matrix, I quickly realized the challenge ran deeper than building an app. I was designing for a population with low digital literacy, complex logistics, and a worldview built on personal relationships — not transactions.

Who I Talked To

3 market vendors
1 cooperative manager
1 association owner

What I Found

63% of farmers can read, but have very low digital literacy
Vendors resist complex technology — they prefer WhatsApp over any app
Consumers trust the vendor's expertise in ways that supermarket self-selection can never replicate
Seasonality is a feature, not a flaw — and any solution that ignores it will fail

"Every day is a challenge because delivery requires a wide variety. If you have little product, customers don't order." — Matheus, Orgânicos do Quintal

Research & Synthesis

Meet Manoel dos Anjos

Cooperative Manager, 48 years old

Manoel uses his phone for everything — but relies on his son for anything beyond calls and WhatsApp. He prioritizes relationships over transactions, sells by pre-order to avoid waste, and has spent decades building trust through quality, not marketing.

He's not the exception. He's the rule.

Behaviors That Shaped Everything

Inventory management is visual and tactile — field notebooks, not spreadsheets
Prices vary by relationship — cooperative members pay less, and that's intentional
Quality is backed by reputation, not certification labels
Logistics are communal — shared trucks, buses, and postal services

Building the Experience

Understanding the user's journey was critical before touching any screen. I mapped out wireflows and user flows for both sides of the marketplace — vendors and customers — to uncover friction points before they became design problems.

Vendor flow

Starting with a wireflow helped align the challenges surfaced in research with real interface decisions. From there, a full user flow outlined every touchpoint in the vendor experience.

Screenshot from 2025-07-17 13-53-06.png

Customer flow

Screenshot from 2025-07-17 13-54-48.png

With the user flows defined, I moved into wireframes to understand what each screen needed to carry — and what it could leave out.

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The Solution

Web Marketplace + WhatsApp Commerce

Web Marketplace (Discovery) ➜ WhatsApp (Purchase) ➜ Delivery

The insight was simple but powerful: don't fight behavior, design with it.

Everyone already uses WhatsApp. Vendors are already selling through it informally. Customers are already comfortable placing orders through messages. The solution wasn't to replace that — it was to give it structure.

Zero friction — browse on web, buy on WhatsApp
Familiar — no new apps to download or learn
Conversational — "I'd like 2kg of bananas" beats any form field
Accessible — works on any phone, any connection

Experience Architecture

For Customers

1. Browse the web catalog (products, vendors, prices)
2. Send a list via WhatsApp: "2kg bananas, 1kg tomatoes"
3. Bot replies with a link for payment
4. Confirmation sent after payment
5. Scheduled delivery

For Vendors Managing the Dashboard

WhatsApp Bot Commands:
/stock banana 50kg 8.90      (product, quantity, price)
/out tomato                  (mark as unavailable)
/price banana 9.50           (update price)
/accept #456                 (approve order)

Usability Testing

The Scenario

Task: "Find and order 2kg of bananas, 1kg of tomatoes, and cilantro through Feirajá."

Participants: 8 users, ages 25–45, familiar with delivery apps

Setup

Duration: 15 minutes per session
Method: Moderated remote testing
Success criteria: Order confirmed by the bot

What We Learned

What Worked

87% task completion — users successfully placed orders
Natural language felt intuitive — "2kg prata bananas" needed no explanation
Vendor credibility landed — years of experience translated into trust
WhatsApp required zero onboarding — people just knew what to do

Pain Points

Vendor selection caused confusion — 3 out of 8 users weren't sure which vendor would fulfill their order
Site-to-WhatsApp transition — 2 out of 8 hesitated at the handoff moment
Price transparency — users wanted to see the total before confirming

In Their Own Words

"I love being able to see the options first and then just send a message."

"Wait — which vendor is going to take my order? João or Maria?"

Design Iterations

Before Testing

Generic "Order via WhatsApp" button
Vendor selection happened inside the bot
No price preview

After Testing

Per-vendor buttons — clear attribution before the order is placed
Price calculator — estimated total visible on the site
Onboarding tooltip — guidance for first-time users

Results

Task completion: 87% → 95%
Higher confidence in vendor selection
Fewer drop-offs at the site-to-WhatsApp transition

Design Decisions

1. Radical Simplicity

One command, one action — /stock not /update_product_inventory
Natural language — "out of tomatoes" over alphanumeric codes
Visual familiarity — a dashboard that feels like a digital field notebook

2. Cultural Preservation

Vendor profiles surface expertise and personal history, not just product listings
Seasonal products are celebrated as a feature, not hidden as a limitation
Fair pricing is maintained — this is not a race to the bottom