Design Liquidity Mining - System Design | WinJob

Problem Statement: Incentivizing Liquidity with On-Chain Emissions

Uniswap/Sushi/Curve-class liquidity mining platform that stakes LP tokens into emission gauges, accrues reward tokens per block, supports boost multipliers and optional lockups, and exposes honest APR after fees and dilution. This section covers problem statement during the understanding phase.

Mechanism

LP providers deposit Uniswap V2-style LP tokens into a MasterChef-style staking contract that tracks reward debt per share
Emission schedule mints governance/reward tokens per block across weighted pools; accrual uses accumulated rewards per share (accRewardPerShare)
Boost contracts (Convex-style) can multiply effective stake without moving underlying LP until withdraw

Farm invariants

On-chain accRewardPerShare and rewardDebt settle claims; off-chain APR tiles are trailing projections tied to a block number.

Failure modes

Reward token hyperinflation when emissions outpace real liquidity utility
Double-claim if reward debt is not updated before balance changes

Interview checkpoint (sec-01)

Quote $2.5B staked LP reference, 120 active farms, and accRewardPerShare monotonicity except emergency pause when a Uniswap/Sushi/Curve interviewer probes depth—not generic Web3 hand-waving.

Staff+ talking point

Frame liquidity mining as capital allocation: emissions buy depth; APR billboards must subtract dilution when TVL spikes

javaOne Dark Pro

1 public final class FarmState { public final BigInteger accRewardPerShare; public final long lastRewardBlock; }

pythonOne Dark Pro

1 TVL_USD = 2_500_000_000
2 ACTIVE_FARMS = 120

typescriptOne Dark Pro

1 export function pendingReward(staked: bigint, debt: bigint, acc: bigint): bigint {
2   return (staked * acc) / 10n ** 12n - debt;
3 }

Why interviewers care

Liquidity Mining interviews reward crisp scope, explicit trade-offs, and failure stories—not generic microservice diagrams.

Interview checkpoint

Name one failure story for Problem Statement: Incentivizing Liquidity with On-Chain Emissions that proves you understand real outages, not happy-path diagrams.

Key Highlights

•LP providers deposit Uniswap V2-style LP tokens into a MasterChef-style staking contract that tracks reward debt per share.
•Emission schedule mints governance/reward tokens per block across weighted pools; accrual uses accumulated rewards per share (accRewardPerShare).
•Boost contracts (Convex-style) can multiply effective stake without moving underlying LP until withdraw.

1	export function pendingReward(staked: bigint, debt: bigint, acc: bigint): bigint {
2	return (staked * acc) / 10n ** 12n - debt;
3	}