Loading...
Open SourceDouble-Entry Payments LedgerNigeria
payments-ledger
payments-ledger is our open-source double-entry payments ledger written in Rust with Axum, SQLx and Postgres. It holds customer wallets, moves money between them and credits deposits from Paystack, the way a fintech app's back end has to.
RustAxumSQLxPostgreSQLPaystackOpen Source
Headline
Open source, CI green
01 The brief
What they needed.
Fintech back ends fail in quiet ways: an entry that does not balance, a balance that goes negative under concurrent transfers, a retried request that moves money twice, or a forged webhook. We wanted a small, readable reference that gets each of those right.
02 Our approach
How we built it.
Every journal entry balances: the database refuses an entry whose postings do not sum to zero.
Concurrent transfers lock the accounts involved, and a Postgres constraint keeps balances from going negative.
Every write takes an Idempotency-Key, so a retried request returns the original response and moves no money.
Paystack charge.success webhooks are accepted only with a valid HMAC-SHA512 signature, and mismatches are held for review.
03 Outcomes
What shipped.
Concrete results, not promises. Each line is something that exists and works today.
Open source on GitHub with CI green
Balanced entries and non-negative balances enforced in the database
Idempotent writes and verified Paystack webhooks
04 Stack
RustAxumSQLxPostgreSQLPaystackOpen Source
Like what you see?
We build every project
like it's our own.
Same process, same attention to detail, applied to your idea. Tell us what you need and we will show you what is possible.