Skip to content
Comandos
All projects
Karta

FinTech — SaaS

Karta App Case Study: Premium Credit Card UX

Product design for Karta's premium credit card app. WhatsApp concierge integration, investment-backed payments, and 85% lower fees.

Impact
1k customers in 12 months
Timeline
90 days
Karta premium credit card app hero on iPhone — live account balance, recent card charges, Karta Points rewards counter and quick-send money actions, rendered on the warm Karta brand backdrop the LATAM high-net-worth launch campaign used in Mexico and Brazil

The premium segment remains with traditional banks, using cards that have fallen behind.

Although several fintech companies are approaching this segment, adoption remains low due to recurring questions.

  • Pay with investments.
  • Operate without commission.
  • Exclusive benefits like F1 or Insurances.
  • Backed by Artificial Intelligence but with human sense.
Challenge

Be Widely Accepted Among an Exclusive Audience

WhatsApp surpasses banking apps in usage. What mix of flows and functions in each channel will drive adoption?

I want to grow as Karta

Results

  • +1k customers in 12 months.
  • 94% Net Promoter Score.
  • 85% saving on transaction fees compared to competitors.

The team

  • 4 developers
  • 1 product designer by Comandos
  • 2 Founders at Karta
Karta premium lifestyle collage — the Karta metal card at Disney, a close-up on black, stacked with other world-class cards, and in its welcome box
Adventure

Defining top 2 challenges identified.

Karta Priority Pass Select benefit in a premium airport lounge
Karta exclusive perks — additional cards, Karta Points, and Exclusive Events
Karta user research session — 20+ interview sessions with users across 5 countries

We Optimize Our Value Proposition

Karta is a US-issued card, secured by the applicant's funds held in the US. Most primary users live in Latin America.

  1. 1

    Business

    A card optimized for travel

    We will not compete for everyday use. We will be the best option when travelling, where users are willing to pay a little more for unforgettable memories when paying with Karta.

  2. 2

    User Research

    An assistant that can do almost anything on WhatsApp

    80% of users have had an unpleasant experience when calling a call center and waiting for hours. Karta automates everything from transaction reviews to VAT refunds in Europe and more.

  3. 3

    Product

    Ease of paying off credit card debt

    92% of users have liquidity in investment accounts (e.g. Webull or Interaudi), not just at their bank.

  • A Card Optimized for Travel : We will not compete for everyday use. We will be the best option when travelling, where users are willing to pay a little more for unforgettable memories when paying with Karta.
  • An Assistant that can do almost anything on WhatsApp : 80% of users have had an unpleasant experience when calling a call center and waiting for hours. Karta automates everything from transaction reviews to VAT refunds in Europe and more.
  • Ease of paying off credit card debt : 92% of users have liquidity in investment accounts (e.g. Webull or Interaudi), not just at their bank.

Advantage

The Lowest Commission Rate in The Brazilian Market

Brazilian credit card market fees comparison Q1 2025 — Karta offers the lowest total commission rate
Seeing the mountain

Aha! moment in Less Than 1 Hour.

To resolve the dilemma, we prioritized Apple Pay / Google Pay, as the card took ~1 week to be delivered.

Karta digital card — Apple Pay activation in the iOS wallet
Karta digital card — copy the virtual card number directly from the Karta app
Karta digital card — ready for Apple Pay with balance and transactions visible

We optimize to deliver value in the shortest possible time.

We made it easier to make your first purchase, either online or using contactless payment.

100% of users use their digital card within 45 minutes

Karta digital credit card used for a contactless tap-to-pay at a LATAM retail point-of-sale terminal — new customer completing their first NFC purchase within minutes of activating the virtual card in the Karta app, before the physical metal card ships

Users are using Karta beyond our expectations.

4 transactions during the first 12 hours

Karta card used online for a food delivery order within the first 12 hours

Both contactless payment in restaurants and online purchases.

Making top

A Bank App For People Without Borders

For high-net-worth clients, we raise the standard. The past is history; the future is Karta.

Facilitate Payments

Up To 5 Ways to Pay your Credit Card Bill

Payment methods: US bank account, Brazilian bank account, Pix, investments, and cryptocurrencies.

Paying the Karta credit card bill — US bank account deposit details and routing
Paying the Karta credit card bill — choose between bank transfer, Pix, investments, or cryptocurrencies

Our concierge can also process the card payment. We just need to ask them to do so.

Facilitate Fast Adoption

Additional Cards For Family Members Or Collaborators

The user can enable a metal or plastic card. All additional cards have digital cards.

Additional Karta metal and plastic cards for family members or collaborators, shown on a mustard sofa

Facilitate Fast Adoption

We Automate Travel Tax Refunds to Europe

Karta automatically detects transactions in Europe and guides users through the requirements necessary to obtain an automatic tax refund.

Karta trip to Europe — transactions detected and grouped by country for VAT refund
Karta Europe VAT refund — airport barcode ready to scan at the refund desk

Purchase invoices can also be uploaded via WhatsApp.

An AI Concierge That Feels Like a Human

Help Buying a Flight or With Your Transactions.

The Karta app is key, but WhatsApp support is essential for an exceptional experience.

Karta AI Concierge over WhatsApp — assisting with a hotel reservation
Karta AI Concierge over WhatsApp — explaining a charge and confirming a payment

Karta Concierge helps you with:

  • Transaction disputes.
  • Your Priority Pass code.
  • Sending money to another Karta user.
  • Cut-off date and outstanding balance.
  • Among others.

Designed For People Who Don't Stop At Limits Or Borders.

Karta black metal credit card photographed at a world-class travel destination — the premium card LATAM high-net-worth customers carry across Europe, the US and Asia for Priority Pass lounge access and no-FX-fee spending
Karta premium metal credit card in hand during a travel moment abroad — the weighty black card the LATAM premium tier ships to every Karta customer as a status signal on trips, hotels and restaurants outside Mexico
Karta welcome kit — card box unboxing with accessories
Karta black metal credit card close-up on a neutral surface

Amazing results in 12 months

+1k Customers in 12 months
A HUGE success. Better than we expected.
$900 USD Average transaction
Average transactions during that period.
85% Savings
Saving on transaction fees compared to competitors.

Keep exploring

Cases that might interest you