Developing X Wallet, A Privacy Focused Mobile Wallet

Justin Smith | @rusticbison

The X Wallet is a free and open source banking app. It delivers the benefits of "private Swiss banking" to anyone with an iPhone.


  • Bitcoin makes engineering tradeoffs which make privacy difficult
  • A separate, more costly technology is needed
  • XCATs, OpenDimes, etc. can be used for swaps
  • Insufficient RAM in mobile devices for ZEC shielded transactions
  • Monero can be deployed now

How can we give more people access to sound digital money?

Mobile "banking" software

We will compete directly with mobile banking as the FOSS "bank" of the future.

How will we succeed?

Through product design excellence and business concept innovation.

We provide direct access to sound-money without compromising usability, security, or privacy.

X Wallet Product Requirements

  • Delight the user without compromising our values or the benefits of the underlying technology
  • Deliver exceptional design and performance
  • Focus is on mobile banking, not card payments

X Wallet Development Requirements

  • Unix philosophy
  • Transparency

Project Execution

  • Hard mode: shoestring budget, no outside funding
  • Expected v1.0 to take about 6 weeks
  • Took about 6 months

How's it going?

  • 1000 < installs since initial release this year
  • Shipped from v1.0 to v1.5
  • No real marketing efforts
  • A few bugs and usability issues
  • Delivered all requirements: project success!
  • But will the underlying technology survive?

Lessons Learned

  • Tried to rebuild libs in swift- don't ever do this!
  • Underestimated totally the crypto behind monero
  • Worked in simulator, postponed compile for devices
  • Build for simulator was fine but for devices failed
  • Apple review process and guidelines
  • Monetization is challenging

What's next?

  • U2F support
  • Continued UI refinement
  • Donation game: vote for features
  • Zcash sapling RAM overhead 40MB...?

Core Team

Programming: J├╝rgen Lotzmann
Design: Rizvi Haider

Special Thanks

Dan O'Leary