Stacking CityCoins
An overview of the stacking component of the CityCoins protocol.
CityCoins require the Stacks Web Wallet to interact with the smart contracts on the Stacks blockchain. (see How do I get started?)
Overview
Anyone can Stack CityCoins by locking them in a CityCoins smart contract for selected reward cycles and receive a portion of the remaining 70% of the STX sent by CityCoins miners.
Reward cycles are 2,100 Stacks blocks in length (~ 2 weeks), similar to Stacking STX.
When Stacking, you must select:
the amount of CityCoins you want to Stack, which will be transferred to the smart contract
the number of reward cycles you want to participate in, maximum 32 (~16 months)
You cannot Stack in the currently active reward cycle, only for the next reward cycle.
e.g. if you select to Stack in a block height in reward cycle 1 then Stacking will begin in reward cycle 2.
There are also code examples, Node.js scripts, and community resources built around Stacking.
For a more technical explanation, please see the contract functions for Stacking and Stacking claims.
Stacking Claims
While Stacking CityCoins is similar to Stacking STX, there are a few key differences.
Instead of rewards being delivered automatically during the cycle, Stackers must wait for the reward cycles to pass before claiming their Stacking rewards, which consist of:
the Stacks (STX) sent by miners
the amount of CityCoins they Stacked, if unlocked
For example, if you Stacked CityCoins for three cycles starting in Cycle 1, then you would be able to claim:
your portion of the 70% Stacks (STX) sent by miners for Cycle 1, after Cycle 1 ends
your portion of the 70% Stacks (STX) sent by miners for Cycle 2, after Cycle 2 ends
your portion of the 70% Stacks (STX) sent by miners for Cycle 3, in addition to the Stacked CityCoins, after Cycle 3 ends
Each Stacker receives rewards proportionate to what they stacked against the total amount of Stacked CityCoins for the given reward cycle.
Common Questions
Do the Stacked CityCoins stay in my wallet?
No, they are transferred to the contract and can be reclaimed once the selected cycles are complete. Some examples are below.
if you Stack 50,000 CityCoins for 1 cycle, then after the cycle ends you can claim the STX rewards for that cycle in addition to the 50,000 CityCoins
if you Stack 50,000 CityCoins for 3 cycles, then after cycle 1 and 2 you can claim the STX rewards for each, and after cycle 3 you can claim the STX rewards in addition to the 50,000 CityCoins
See the table under Can I stack additional tokens for a cycle? for another example.
Is there a minimum amount for Stacking?
No, however the STX rewards for a given cycle are proportionate to the amount you Stack versus the total Stacked in that cycle.
If the amount you Stack in CityCoins entitles you to less than 1 uSTX (0.000001 STX) then no reward will be received.
Can I change the duration of CityCoins I've already Stacked?
No, once stack-tokens is called the CityCoins are transferred to the smart contract and the values are set. There is no way to update it.
Is there a cooldown between cycles?
Yes, when you are finished Stacking and reclaim your CityCoins, you can then stack for the next cycle. An example with MiamiCoin (MIA):
A user submits a Stacking transaction at block height #26386 for one cycle
Since block #26386 is part of Cycle 0, the MIA are Stacked for Cycle 1
After Cycle 1 finishes at #28696, the user can reclaim their STX rewards and their Stacked MIA
The user submits a Stacking transaction at block height #28697 for one cycle
Since block #28697 is part of Cycle 2, the MIA are Stacked for Cycle 3
After Cycle 3 finishes at #32896, the user can reclaim their STX rewards and their Stacked MIA
Can I Stack additional tokens for a cycle?
A: Yes, if you call the stack-tokens function before the next cycle starts, you can add to the amount Stacked as well as choose different amounts for a different number of cycles.
In a more complex example:
the user has 1,000,000 CityCoins to Stack
the user calls
stack-tokensduring cycle 3 with 250,000 for 1 cyclethe user calls
stack-tokensduring cycle 3 with 250,000 for 2 cyclesthe user calls
stack-tokensduring cycle 3 with 500,000 for 3 cycles
The payouts would then be based on the amount Stacked by the user R, the total STX reward that cycle S, and the total of all Stackers Tusing the formula: STX Rewards = (R * S) / T
Reward Cycle
Amount Stacked
Claimable Amount
STX Rewards
3
none
none
none
4
1,000,000 CityCoins
none
(R * 1,000,000) / T
5
750,000 CityCoins
250,000 CityCoins
(R * 500,000) / T
6
500,000 CityCoins
250,000 CityCoins
(R * 500,000) / T
7
none
500,000 CityCoins
none
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