Rafael Dionísio Toledo, Developer in São Paulo - State of São Paulo, Brazil
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Rafael Dionísio Toledo

Verified Expert  in Engineering

Mobile Developer

São Paulo - State of São Paulo, Brazil
Toptal Member Since
November 23, 2022

Rafael is a mobile developer with a bachelor's degree in information systems. He specializes in native Android development and has experience writing multiplatform Flutter apps. Rafael has worked for companies in various industries, including finance, media, commerce, and education.


Android, Kotlin, Java, Mobile App Testing, Mobile Analytics
Android, Android Studio, Kotlin, Proguard, DexGuard, Native Mobile Apps...
Concrete Solutions (now part of Accenture)
Android, Java, Kotlin, Flutter, Google Play Store, Gradle




Preferred Environment

Android, Kotlin, Flutter

The most amazing...

...thing I've developed is a banking app from scratch, with the 2-person development team scaling to around 20 mobile developers and shipping the app in one year.

Work Experience

Senior Android Engineer

2019 - PRESENT
  • Built the Share My Trip feature for passengers and drivers. It enabled users to share their location with contacts or generate a link showing their real-time location that could be accessed through the Uber app or a browser.
  • Developed the Trusted Contacts feature, enabling users to add emergency contacts in case of incidents during a trip.
  • Contributed to a feature that allowed users to request a trip for someone else using their account.
Technologies: Android, Kotlin, Java, Mobile App Testing, Mobile Analytics

Lead Developer Consultant

2018 - 2019
  • Became a part of the founding team of a new bank, C6 Bank.
  • Implemented the MVP, allowing the client to ship high-quality native mobile apps for their launching, including all main features, like account creation, checking account, payments, and credit card.
  • Defined and implemented the design system and app modularization, allowing the mobile team to scale to more than 20 developers working in parallel on different features.
  • Implemented the new onboarding experience in the form of a chat, allowing users to have a more pleasant experience on their onboarding, and increasing the conversion of new clients.
  • Worked on several security features, like HTTP pinning, app obfuscation, and anti-tampering, and integrated several third-party SDKs during the development.
Technologies: Android, Android Studio, Kotlin, Proguard, DexGuard, Native Mobile Apps, Mobile Applications, Mobile Apps

Senior Android Developer | Engineering Manager

2015 - 2018
Concrete Solutions (now part of Accenture)
  • Contributed to the Android implementation of a couple of apps for every major soccer team in the Brazilian league for a cable TV channel (SporTV), which included videos, news, and real-time scores.
  • Worked on the first version of the mobile app of one of the biggest stores of sportswear, shoes, and fitness equipment (Centauro). We could push a native app built from the ground up in less than four months.
  • Developed the internal network and security SDK from a major Brazilian bank (Itaú), allowing different teams to ship their apps and integrate with the bank's internal APIs. The features of the SDK included networking, authentication, etc.
  • Acted as the engineering manager of the Android team. I paired with another manager to grow the team to about fifth developers working on different projects. We took care of technical improvements, individual 1:1s, and team allocation.
Technologies: Android, Java, Kotlin, Flutter, Google Play Store, Gradle

Android Developer

2014 - 2015
MakeYou Inc.
  • Implemented the native Android app from the ground up, integrating with the internal REST APIs to deliver real-time social interactions between fitness group members.
  • Enabled real-time notifications to track progress between group members and implemented a native implementation of their design system, including dynamic app theming based on challenge statuses.
  • Added several observability mechanisms, including analytics and crash reporting. Automated several version deploys, including distributions using internal tracks and integrations with Google Play console.
Technologies: Android, Java, Eclipse, Android Studio, Gradle, Mixpanel, Firebase

Zuby – Android App

Implemented the new native Android app from the ground up, integrating it with the existing REST APIs and utilizing Plaid to support tenants in paying their rent. I worked on the app's architecture, converted it to Kotlin, and integrated Firebase libraries, which now include analytics, crash reporting, and internal distribution.

CNA Go – Flutter App

Assisted the team in implementing their design system library, allowing them to iterate on new features quickly. I implemented several parts of the app, including the signup, home screen, and progress tracker.

Knowe – Android App

Built Knowe, a native Android app from the ground up, integrating it with REST APIs. The app included a social login integrated with Facebook SDKs, payments through MercadoLibre and Stripe, and real-time video chats using OpenTok.
2008 - 2011

Bachelor's Degree in Information Systems

FAI – Center for Higher Education in Management, Technology and Education - Santa Rita do Sapucaí, MG, Brazil


Stripe, Proguard


Gradle, Android Studio, Plaid


App Development


Kotlin, Java, Dart, GraphQL


Android, Firebase, OpenTok, Eclipse, Mixpanel




Mobile App Testing, Mobile Analytics, Google Play Store, DexGuard, Native Mobile Apps, Mobile Applications, Mobile Apps

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