Mandinga

Communities across every continent invented savings circles independently, and for good reason: it works.
Mandinga takes that same cooperative logic and makes it structurally sound at scale.

The problem it solves
Pool contributions, rotate the full amount to one member per round, everyone gets access to meaningful capital sooner than they could alone.
The problem is structural: the member who receives the pool first can simply stop contributing and walk away. Everyone waiting loses what they put in. Institutionalising the circle, as Brazil did with the consórcio, solved this but introduced new ones. Auction mechanics that let capital purchase earlier access. Fee structures that charge the same regardless of when you're served. Scale or keep the cooperative logic. Every attempt so far has had to choose.

What it is
Mandinga is a savings primitive with two layers. A self-custodial savings account where deposits earn yield automatically. And a savings circle where the pool rotates to one member per round, selected by Chainlink VRF, verifiable and unmanipulable by anyone.

How it works
Members browse open circles defined by installment size and duration and join one that fits what they can afford. Once a circle fills, the rotation starts. Chainlink VRF selects who receives the pool first, keeping the rotation fair and equal for every member regardless of capital. A Safety Net Pool covers members who can only pay half their installment in a difficult month, keeping the circle running. When a position is activated, the pool stays locked in the protocol earning yield while remaining obligations settle.
The direction we are building toward is making that activated position a verifiable claim to acquire a real asset, a vehicle, equipment, a home. The protocol holds a stake in the underlying asset until all obligations are met. When the circle completes, ownership transfers fully to the member.

Mandinga is built with smart contracts in Solidity using Foundry, a Next.js 14 frontend, and Chainlink CRE workflows written in TypeScript running on Bun.
Chainlink is used in three ways. VRF v2.5 handles selection order — every round, executeRound() requests randomness and fulfillRandomWords() applies the result, making the rotation verifiable and uninfluenceable by anyone. CRE workflows automate the protocol's critical operations on a Decentralised Oracle Network: circle formation runs on a hourly cron checking member intents and yield viability, yield harvest routes deposits to the Spark USDC Vault daily, and two additional workflows monitor the Safety Net Pool and trigger reallocations when needed. Chainlink Data Feeds via AggregatorV3Interface are scoped to v2 for multi-source yield rate aggregation.
Yield in v1 is routed to the Spark USDC Vault on Base, using the Sky Savings Rate. Member balances and contribution history use a bytes32 shieldedId throughout state and events, keeping addresses off-chain as a foundation for the full privacy layer in v2.