- Smart Brazilian Fiat-to-Crypto over Zcash

Applicant background

Our privacy-needed team has multiple backgrounds, from Software Engineers to Social Scientists, Designers and Bread Bakers, all united last century on a small telegram Brazilian group for P2P cryptocurrency trades avoiding big national Exchanges.

Rafael Polo was the chosen public name for this proposal, a Msc. Computer Scientist who have being developing dozens of tools and full stack software for more than two decades. From projects with artists in Rio de Janeiro to activists in Berlin. From opening Computer Labs in Athens, to speculating with basic income in Lisbon.

Motivation and overview

A few weeks ago, Brazilian Central Bank implemented a national-wide system called PIX, a non-blockchain system and policy that pushes any inter-bank transfer to happen in just a few seconds, upgrading the previous years-old TED and DOC methods that could cost up to 5 dollars and take 48 hours. It is a big change that brings new opportunities. To invest also became less risky. PIX was well received but the distrust in the actual government and the Ministry of Economy still pushes crypto new-comers to P2P methods, far from possible unfair taxation.

For years focusing on privacy strategies to avoid the ID-and-data-suckers Exchanges like MercadoBitcoin, our community grown lots and we now have a private channel with a few core members, who organized a poll of cryptocurrency sellers and a smart contract to guarantee instant trade direct from Brazilian Real fiat currency. For years we used a ETH-XRP solution, but now we are confident that Zcash is the way to go, since we share a similar mission.

Brazil is an extraordinary case for cryptocurrency, not only because our BRL currency was one of the most devaluated this year, almost 30%, but Bitcoin is on the trend topics on most social media, where our almost-3% of world-population struggle for fair financerization in one of the higher bank taxes in the world.

For all of this we join years of in-house talks and skills into, a privacy-oriented system to allow people to access +150 cryptocurrencies direct from fiat/BRL. This proposal would allow our enthusiastic developers to fully focus on this work next months.

Technical Approach

We have a Debian VPS with a Ruby/Sinatra +Postgresql +Nginx +Sidekiq workers dealing with dozens of APIs and financial methods that defines the best price for +150 cryptos, assuming a 20m window for an ideal BRL/PIX trade to execute it and get a 0.1 ZEC per trade. We would love to make it as decentralized as possible in a future stage, beyond actual frame.

The innovation from our side is a pool of trusted crypto dealers that are the only KYC (we call know-your-dealer KYD) able to get BRL/PIX transfers and execute our crystal-lang-based smart contract and get a small %, as fiat-to-crypto miners. Over our contract, the dealer now uses a ETH-ZEC swap to our side who match the best strategy to provide the user with his requested crypto in a few seconds.

This has already being happening in a closed telegram group, and it is time to open it up.

Execution Risks

Imagined obstacles were

1) Government agencies pushing to close the domain? Move to namespace

2) Crypto-dealer has no funds for transaction? Move to next, this should be improved in the contract. Never happened.

3) Crypto-dealers becoming scarce? Incentive more.

4) Do our Nginx configurations on Scaleway hold DDOS Attacks? Well, we have lots to learn.

5) Algorithmic errors regarding the API? We have good sysadmins and we need to catch and keep an eye on it all. We have in our team knowledge enough to scale it, anyhow.


Even interested in a efficient censorship-resistant network and system, we might have to discuss and find ways to detect and moderate patterns of big trades or any money laundering activity.

Evaluation Plan

Our goals are

1) Push our poll of trades to use Zcash

2) Bring awareness to our users (10k viewers/month) to have privacy-orientated decisions while trading.

3) Use Zcash as an anonymity layer on all our atomic swaps, and have this domain “powered by Zcash” all 2021 in the footer, if this proposal is approved.

4) Enhance and test more our Smart Contract

5) Open to the public our system, after years of in-house trades.

6) Publish monthly statistics on Zcash community forum


January) 1# and 2# and 3# - Write a why-Zcash brazilian manifesto for our traders and dealers, and link on the main page, while working on #4

February) Open to the public #5 and follow statistics. Publish on Zcash community forum what we are having and what we have learnt.


Dev team $2,200/ month

UX designer. $1200/ month

External services (VPS) $150/ year

Team work (2 months): $6800

Total: $6950


Tips Received


2 years ago
Funded through  Zomg logo
New system + funded by ZCash

New system + funded by ZCash

Reward: $6,950
The team was awarded $6,950 in ZEC as an initial payout on Jan 27th, 2021, 12:24 am.
website will be fully online and all system tested and running over Zcash