Haven Launches xUSD Stagenet Utilizing Chainlink Oracle

Haven Protocol
4 min readMar 10, 2020


The Haven Vault has been updated for xUSD stagenet

Today Haven is launching a stagenet for its first private stablecoin, xUSD. The stagenet deploys a new daemon and utilizes a Chainlink pricing oracle. Below are some additional details and instructions for participating.

Testnet vs. stagenet

We’ve built out a more complete testing suite to accommodate different tiers of testing. This is in keeping with standard software production processes. The network inherited by the current Haven team (early 2019) used an incomplete testnet (e.g. no wallet address for governance, code lacking the proper logic, etc).

Moving forward, our development environments will look like this:

Mainnet = live production environment.

Stagenet = staging area for (typically public) testing of code for next release.

Testnet = (normally private) area for testing of internal-only code/new features.

We spent several days trying to reboot the existing testnet to implement the new daemon and Chainlink oracle, but this resulted in a large number of legacy transactions. So the decision was made to prepare a clean stagenet for public launch and for protocol upgrades going forward.

Stagenet is technically a step closer to mainnet launch, both in terms of features and consensus rules.

Participate in the xUSD stagenet

We would like to invite anyone interested in trying out the xUSD exchange process to join the stagenet. Below are some important instructions for participating. Please read them carefully.

You can download the stagenet Haven Vault here:

MacOS: https://github.com/haven-protocol-org/haven-web-app/releases/download/v1.1.0/Haven-macos-x64-1.1.0.zip

Windows: https://github.com/haven-protocol-org/haven-web-app/releases/download/v1.1.0/Haven-win-1.1.0.Setup.exe

Please note: this is only a stagenet using test addresses and test XHV. Do not send any real XHV to a stagenet address. All Haven stagenet addresses begin with “hvs…”.

To receive test funds, you can either enable background mining of XHV (under the “Settings” tab) or you can join the testing channel in Haven’s Discord and post your Vault address. There are many active team and community members in this channel who would be happy to send you test funds.

Please try out all the features included in the Vault. The most important are the exchange functions: XHV to xUSD and xUSD to XHV. The stagenet explorer can be found here. The decentralized pricing oracle, utilizing values provided by Chainlink, can be found here.

Chainlink oracle

We have successfully deployed a custom XHV/USD oracle with the Chainlink team. We are using this oracle for today’s stagenet testing and will use it for the mainnet launch of xUSD. More details about our collaboration with Chainlink will be available shortly.

Supply transparency

Providing a public and transparent way to calculate the circulating supply of xUSD (and future xAssets) has been a key development priority for the Haven team over the last few months. It also proved to be a significant technical challenge. The circulating supply solution is now fully coded and RPC calls are working as planned in stagenet testing.

This was accomplished by adding a publicly verifiable supply amount to each xUSD exchange transaction. By adding a second amount (which, prior to masking is identical to the first amount), any wallet or interested party can sum up the unspent outs for xAsset exchange transactions to audit circulating supply for both.

Once on mainnet, this can be done via the Haven explorer and be made available publicly. We believe this solution offers the minimal possible amount of visible data points while staying true to the principle of auditability for private cryptocurrencies. Importantly, this does not compromise the privacy of user addresses, balances, or transactions.

xUSD exchange fees

xUSD exchange fees were implemented to punish manipulation attempts, not to tax network usage. These fees were proven to be very low in the previous xUSD testnet. For most exchange transactions, fees are zero or very close to zero. We will handle these fees transparently and discuss their current future use with the community.

In the new daemon, XHV to xUSD exchange fees are now being successfully directed to the Haven governance wallet. The inputs and outputs from wallets are all matching up as we hoped and we’re seeing xUSD in the governance wallet as planned.

The correct implementation of fees has been complicated but is complete. For example, the team discovered xUSD to XHV fees were being paid for in xUSD, but then landing (as the same number not the same value) in the miner_tx as XHV. This has been corrected.

Governance wallet funds are used to support our full-time developers and costs associated with project infrastructure, legal, and marketing activities. We plan to continue consulting with the Haven community about the use of these funds moving forward.

Timing for mainnet launch of xUSD

Today’s stagenet launch of xUSD, utilizing a new daemon and the Chainlink oracle, is a critical step forward in our preparations for mainnet launch.

There is more testing to do over the coming days, but we expect to be able to announce a xUSD mainnet launch date soon, barring any unforeseen delays.



Haven Protocol

Ecosystem of private stable assets. Based on Monero. The world's first private stablecoin xUSD is now live.