Ajo
Digital savings circles with Naira wallets, a double-entry ledger, Paystack funding, and automated payout rounds.
Role
Full-Stack Developer
Year
2026
Status
Live
Stack
TypeScript · PostgreSQL
Overview
Ajo brings the familiar rotating savings circle online: members fund individual wallets, contribute on a set schedule, and receive the full pot when it is their turn. The product keeps every movement traceable without asking one member to hold the group's money.
What it does
Naira wallets with card and bank-transfer top-ups through Paystack
Double-entry ledger with balances derived from immutable entries
Scheduled contribution collection and rotating payout rounds
Shareable circle invites with membership and schedule visibility
Idempotent payment and ledger writes to prevent duplicate charges
Transparent missed-payment records for every circle member
The hard part
Money movement needs to remain correct when a payment is retried, a webhook is delivered twice, or a scheduled round runs more than once. Idempotency keys and database transactions ensure each movement is settled exactly once or not at all.
What it taught me
For a financial product, the ledger is the source of truth. Deriving balances from matching debit and credit entries makes both the system and its audit trail easier to trust.