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Senior iOS Developer (Hanoi)



Software Engineering
Hanoi, Vietnam
Posted on Friday, May 12, 2023

Krystal is the simplest self-custodial wallet for Web3. On a single application, access cutting-edge portfolio management & market insights tools, swap & bridge tokens, earn passive income and participate in token sales via its IDO launchpad, KrystalGO. Additionally, users earn points and rewards from in-app activities as part of its loyalty program.

Krystal currently supports DeFi services on 11 blockchain networks, including Ethereum, BNB Smart Chain, Polygon, Avalanche, Fantom, Cronos, Arbitrum, Aurora, Klaytn, Solana, and Optimism. Krystal is available on both mobile app (iOS and Android) and web app. Our offices are located in Vietnam and Singapore.

Job Introduction:

We are looking for a senior iOS engineer to join our team to build a cryptocurrency wallet application. The successful candidate will be responsible for developing a secure, user-friendly, and high-performance iOS application that allows users to manage their cryptocurrencies and comfortably use Web3. You will be working closely with a team of developers, designers, and product managers to deliver a high-quality product, as well as researching and evaluating new technologies to continuously improve our products.


  • Collaborate with cross-functional teams to develop, test, and deploy a user-friendly mobile wallet app
  • Ensure that the app is performant and responsive on a variety of devices
  • Build secure, reliable, and high-performance iOS applications
  • Write clean, scalable, and maintainable code that adheres to best practices and coding standards
  • Stay up-to-date with the latest iOS technologies, cryptocurrency, and Web3 developments and apply them to your work
  • Ensure the app meets industry standards for security and encryption, including adherence to best practices for key management and secure storage of private keys
  • Integrate with different blockchain networks to enable the management of multiple cryptocurrencies
  • Research and evaluate various web3 protocols and technologies to determine their suitability for adoption in our products and services
  • Design and implement web3 adoption solutions to enable secure and efficient transaction processing and management
  • Work closely with other teams to ensure seamless integration of web3 adoption solutions into existing systems


  • Bachelor's degree in Computer Science or a related field.
  • At least 5 years of experience in developing iOS applications using Swift and Objective-C programming languages.
  • Strong understanding of iOS performance optimization techniques and best practices.
  • Strong experience in developing user-friendly interfaces for iOS applications.
  • Experience in developing secure mobile applications with a focus on mobile security best practices and encryption techniques.
  • Excellent communication and collaboration skills to work with a team of developers, designers, and product managers.
  • Experience in leading a team of iOS developers and delivering high-quality code in a timely manner.
  • Comfortable working in an agile development environment and using version control tools like Git

Nice to have:

  • Familiarity with blockchain and crypto currency technologies, including web3, smart contract implementation, and interaction
  • Familiarity with cryptographic algorithms and protocols used in the crypto currency industry


  • Flexible working hours, standard leave policy of 14 days/year.
  • Hybrid working time with 1 remote day/week.
  • Opportunity to be offered token package in Early Stage.
  • Equipment Support Package up to $3000.
  • Holidays bonus, working anniversary bonus.
  • Gifts for other celebrations: Lunar New Year, Mid-Autumn Festival, March 8th, June 1st, wedding day, childbirth, etc.
  • Opportunity to be supported by the 5-million-USD Kyber Alumni Fund when starting own blockchain startup project.
  • Internal training activities, extracurricular activities, and team-building.
  • Birthday leave, Childcare leave.
  • Annual health check-up at a reputable hospital. Additional Premium Health Insurance package for accident, inpatient, outpatient, and dentist expense.
  • First-class facilities and working conditions, and an open, dynamic and friendly working environment, prioritizing the employee development and innovation.
  • Other policies: compliant with Vietnam Labor Law and Company’s Labor Regulations.