Zcash is Unstoppable [AMA]

Hi Zcashers.

It’s my pleasure to introduce you to @iBek, the founder of Horizontal Systems. Today, they announced that Unstoppable Wallet has added support for shielded Zcash on mobile (Android, with iOS to follow later this week). You can view ECC’s blog post here.

I personally love using this app and hope you find it has a great user experience. Let’s give them a warm welcome and feel free to read more about their history and why they decided to focus on Zcash below.

Can you give the history of Unstoppable?

In 2018, we embarked to engineer a cryptocurrency wallet. Most wallets around back then were either desktop based apps or pseudo wallets working in a centralized manner.

We wanted a wallet that’s to large extent decentralized, doesn’t depend on centrally managed servers and gives users unconditional control over the assets and privacy.

What is the background of the team and how did you get started?

Our team came together around 2013-2014. Back then we were building native mobile messaging apps for small and midsized organizations. The messengers were just getting started back then and we thought community focused messenger apps may just very well replace the traditional forums :slight_smile:

We spent about 3 years on the project and have had several high profile clients at some point. As there were a number of competing products such as Slack which dominated desktop platforms our focus was on the mobile ecosystem.

While working on the project we have gained significant experience in developing high performing mobile applications.

What is your vision for the Unstoppable wallet?

Unstoppable is a wallet built specifically for cryptocurrency investors with a heavy focus on decentralization and privacy. We expect the wallet to become a one-stop shop for buying, selling and storing pretty much any cryptocurrency, from anywhere, and without relying on any intermediary services.

Investors that are currently coming to cryptocurrency space are in dire need of well designed instruments ranging from monitoring to trading. Most cryptocurrency wallets offering this capabilities currently do that via some regulated centralized service provider. This results in fairly low privacy, pseudo control over the funds and regulatory hassle.

Unlike alternative products we only explore solutions which are built on top of the blockchain and are not centralized. As a result our users get to enjoy an unmatched level of privacy and control over the funds.

Moreover, Unstoppable is designed for non-techies with emphasis to guide users through all intricacies of using cryptocurrency in a seamless manner. A lot of currently popular wallets are way too complicated, even for those working in the field :slight_smile:

Why was privacy important for you when designing the app?

Concepts like independence, security and data privacy are closely related to ideals of cryptocurrency. It’s hard to find a believer in cryptocurrency who takes these notions lightly.

So, in case of the wallet app, making it as private as possible was more of a fundamental necessity rather than a choice. Wallets failing to provide privacy mechanisms or features ensuring unconditional control over the funds are likely to fade away as the industry grows simply because there is an ideological conflict.

It should further be noted that information privacy is a multi-faceted concept when it comes to internet enabled software products. As a result, when it comes to mobile apps a privacy sensitive user may have fairly steep requirements. In case of Unstoppable, it scores relatively high on many privacy aspects and while leaving place for improvement in some areas which we will try to address in the coming months.

What was your motivation to add support for shielded Zcash?

There is a growing demand for privacy enabled cryptocurrency. The major blockchains like Bitcoin and Ethereum come with minimal privacy leaving privacy conscious users without options. While the Unstoppable app anonymizes users’ interaction with the blockchain, the actual transactions on Bitcoin blockchain leak a lot of information which may expose user’s balance and past transactions with a minimal effort.

Zcash is one of the few cryptocurrencies out there that goes with privacy out of the box and a strong community. The availability of Zcash on major cryptocurrency exchanges was an added incentive for us to integrate Zcash. In combination, these two features allow any individual to seamlessly purchase Zcash on regulated exchanges but after that continue to transact anonymously.

How was the experience of adding shielded Zcash into the app?

Actually it was an easy task. The lite client SDKs that you provide already had pretty much everything we needed for integration. Your mobile client development team did a good job. In fact it was the easiest integration we had so far :slight_smile:

The team was responsive and promptly addressed all the concerns we had. Typically, we have been struggling with this on some other blockchains where teams were slow to address/reply to our concerns.

Is there anything you would like to see from Zcash in the future?

There are some minor points but nothing substantial. From a perspective of the wallet app the availability of network nodes adopted to serve light clients would help. This would enable users to choose a trusted public node rather than relying on some node client managed by some centralized entity.

The issue isn’t critical as we plan to allow users to use their own network node for any supported blockchain including Zcash. For non technical users we are contemplating a simple mechanism to setup private network nodes (using crypto on balance) via some trusted third party such as Ankr network.

You submitted a Gitcoin Grant request. Could you describe what features you intend to build with the grant?

After Zcash support in Unstoppable goes live mid November we then wanted to further expand feature set for Zcash users by integrating following features:

  1. ability to trade ZEC for ETH/ERC20 in a non-custodial and decentralized manner. We are planning to achieve this by integrating support for REN blockchain protocol. In combination with the support for Ethereum’s Uniswap protocol (which we already support) we will be able to provide a seamless private and non-custodial trading between Zcash and ETH (including any other ERC20 token).

  2. ability to configure client to communicate with a Zcash blockchain over a personal Zcash node as well as ability to connect over VPN. That would be a huge incentive for ultra privacy conscious Zcash users.


@iBek congratulations on the release! It has been great working with you and your team. I’ve downloaded the Android wallet from the play store and I’m syncing it as we speak! The integration is so smooth. You’ve done a great job!

Since this is an AMA, here are some questions:

  1. Your team is doing a great job supporting both Native platforms. What tips do you have for keeping iOS and Android codebases in sync?
  2. In general, how has Tor integration gone for the Android and iOS wallets?
  3. What’s the approximate level of difficulty to add Tor support for Zcash in Unstoppable Wallet (related discussion on using Tor with gRPC via HTTPTunnelPort)?

Your team and your wallet are fantastic. Congrats again!


By the way, the iOS wallet is available. I have downloaded it a few days ago.

EDIT: I downloaded it but didn’t actually have time to even test it. I just tested it and Zcash is not available yet. I guess it will be in the next update.


Nice!! Received & sent funds, very slick.

I can’t get tor to work, perhaps that involves more than just checking a box? Does it handle ZIP321 qr codes…mmm…new toy!!

EDIT: Yep, tor works, problem was me being impatient.


Yep, they’re stuck in the Apple review process but it sounds like a misunderstanding on Apple’s end so that should clear up, hopefully, soon.

Hi Kevin,

Thanks, it was a pleasure for us as well! Your team did a great job with SDKs and were prompt to address our concerns :slight_smile:

  1. re: keeping platform in sync.

On our end we achieve this by working on the same tasks in parallel. Typically it would be two devs from different platforms would sit together and work either on iOS/Android first. When we are happy with everything on one platform we quickly migrate it to the other one. It doesn’t work in all cases but for the most part that approach enabled us to move quickly although it may seem slow at first. Most of the larger tasks are done this way.

  1. re: TOR

On Android it was quick and through but on iOS it’s incomplete and currently disabled. Our experience with using client over TOR been pleasant. There was no good library we could use for TOR on iOS so we had to choose whether to put a couple of months on the task and write it ourselves or postpone it. We decided to postpone as there were a number of other pressing features we wanted to integrate.

At this point we prioritized integrating VPN support. It’s a simpler task for us and would enable private communication (with all external services while using the app) for those that have such requirements. There are some smart contract Ethereum-based projects offering VPN services that we would like to explore.

  1. re: TOR for Zcash

At some point few months back we created a Lightning wallet app. It’s in dev stage and haven’t been released to the public. So, within that context we explored getting TOR to work over GRPC as the Lightning nodes provide GRPC API. Back then we had fully working Android client so I suspect we didn’t have any issues but I will double check to make sure and followup.


The iOS version 0.17 of Unstoppable is pending approval from the App Store. Hopefully it will be available within a couple of days.

awesome, let us know your thoughts once you have played around with it

@iBek Regarding Tor on iOS, there are absolutely no issues with it. I use OnionBrowser that bundles latest Tor and it works fine.

Update: Unstoppable has released a guide for iOS users to take advantage of improvements in the beta version while they wait for a response from the App Store. More soon…


Unstoppable’s shielded Zcash wallet is now live on iOS! Thanks @iBek for working through Apple’s app store requirements to get this launched.


Thanks Andre)
Sorry it took longer than expected :pray:t2:


This feature is super exciting!

If someone starts with Zcash only, will they be able to complete the transaction? Or will they need some ETH to cover the exchange fee?

good question!
yep, some amount of ETH would still be required to complete the exchange