MiamiCoin How-To Guide

What is MiamiCoin?

MiamiCoin (MIA) is the first CityCoin to market, going live soon. MiamiCoin is a cryptocurrency powered by the Stacks Protocol, which enables smart contracts on Bitcoin.

MiamiCoin provides an ongoing crypto revenue stream for the city, while also generating STX for MIA holders. MiamiCoin can be mined or bought by individuals who want to support the Magic City and benefit from the Stacks protocol.

Mining MiamiCoin directly benefits the city of Miami by automatically directing STX to a wallet reserved for the city. MiamiCoin benefits holders by allowing them to Stack and earn through the Stacks protocol.

The city of Miami can elect to use its growing crypto treasury to benefit the city and its constituents — think new public spaces, improvements to infrastructure, hosting city events, recruiting startups, and more.

Stacks Web Wallet

The Stacks Web Wallet is required to interact with the MiamiCoin smart contract on the Stacks blockchain.

It is a browser extension available for both Chrome and Firefox, and at this time the actions below are intended to be performed from a desktop or laptop.

In addition, each of the actions below requires sending a transaction to the smart contract, with transaction fees paid in Stacks (STX).

How to Acquire Stacks (STX)

As mentioned above, all transactions with CityCoins require Stacks (STX) as fuel.

To acquire Stacks, please see the market list on CoinMarketCap for supported exchanges.

How to Hold MIA

MiamiCoins are a fungible token on the Stacks blockchain, meaning they are stored, displayed, and used in the Stacks Web Wallet in the same way as STX tokens.

Activation of Mining

MiamiCoins can only be mined, and there are no MiamiCoins issued or distributed prior to the start of mining.

In order for mining to begin, 20 unique wallets are required to signal activation, after which a 150 block (~24 hour) countdown begins then anyone is eligible to mine the MiamiCoins within a given Stacks block.

Mining MiamiCoin

Mining MiamiCoins is performed by transferring Stacks (STX) tokens into the smart contract in a given block, and is a one-way process. Miners can only participate once per block.

Once the STX tokens are sent into the contract, they are distributed in one of two ways:

- if there are people Stacking MiamiCoins, then 70% of the bid is sent to Stackers and 30% of the bid is sent to the custodied wallet for the city
- if nobody is Stacking MiamiCoins, then 100% of the bid is sent to the custodied wallet for the city

‍Please note: Right after mining is activated and during the first reward cycle (reward cycle #0), 100% of all STX sent by miners is transferred to the city. During this time, MiamiCoins can be stacked for the next reward cycle, and following this initialization Stacking will be available indefinitely.

Winner Selection

After miners send their STX bid, a winner is selected by a Verifiable Random Function (VRF) weighted by the individual miners' bid compared to the total miners' bids sent in that block.

e.g. if Alice sends 10 STX into the contract and Bob sends 30 STX, then Alice has a 25% chance and Bob has a 75% chance to win in that block.

Mining Strategy

You can only submit a mining bid once per block. Once that transaction confirms then the bid is locked in - it is a one-way transfer.

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Claiming Mining Rewards

Miners must wait for a maturity window of 100 blocks (~16 hours) before they can claim their tokens in order to protect the VRF seed. After this window passes miners can claim their rewards at any time.

‍Please note: MiamiCoins are not minted until miners claim them, and therefore the total supply will only increase when miners claim their MiamiCoins.

Stacking MiamiCoin

Stacking MiamiCoins is performed by transferring MiamiCoins into the smart contract for a selected number of reward cycles. Reward cycles are 2,100 Stacks blocks in length, or about 2 weeks, similar to Stacking STX.

When Stacking, you must select:

- the amount of MiamiCoins you want to Stack, which will be sent to the smart contract
- the number of reward cycles you want to participate in, maximum 32

‍Please note: the block height chosen for Stacking will automatically select the next reward cycle to start Stacking MiamiCoins. e.g. if you submit during a block height in reward cycle 1 then Stacking will begin in reward cycle 2.

You cannot Stack in the currently active reward cycle.

Claiming Stacking Rewards

While Stacking MiamiCoin is similar to Stacking STX, however there are a few key differences.

Instead of rewards being delivered automatically during the cycle, Stackers must wait for the number of chosen reward cycles to pass before claiming their Stacking rewards, which consist of:

- the amount of MiamiCoins they Stacked
- the Stacks (STX) sent by miners

Each Stacker receives rewards proportionate to what they stacked against the total amount of Stacked MiamiCoins for the given reward cycle.

Issuance Schedule

Please see the Issuance Schedule for more information on how MiamiCoins will be distributed over time.

Block Time

Stacks blocks are 1:1 with Bitcoin blocks, and a new one is created every 10 minutes on average. All times referenced in this document operate off the the number of blocks, and any other times are estimated by this average.

Additional Information

Below are some key links from the CityCoins GitHub project for more information:

- CityCoins organization on GitHub, which contains all repos and more information
- CityCoins Product Requirements Document, which contains the project goals in more detail
- CityCoins Documentation Website, which contains the same information listed above and more