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Engineering Notes
from Production

Fintech, security, and systems written from real launches

Field-Level Encryption in Nigerian Fintech: How I Protect BVN and NIN Data with AES-256-GCM

Fintech · 7 min read

Field-Level Encryption in Nigerian Fintech: How I Protect BVN and NIN Data with AES-256-GCM

Olatunde Success explains the field-level encryption architecture he uses in production Nigerian fintech systems: why AES-256-GCM, how key rotation works with JWT auth, and what NDPA 2023 actually demands from engineers.

Building Podus AI: Lessons from Shipping an AI Legal Assistant on Web, Mobile, and WhatsApp

AI · 8 min read

Building Podus AI: Lessons from Shipping an AI Legal Assistant on Web, Mobile, and WhatsApp

How Olatunde Success and the Citizens’ Gavel team shipped Podus AI, an AI legal assistant trained on Nigerian and UK law, across three channels, and what real legal interventions taught the team about AI in high-stakes domains.

Escrow Engines in Practice: What Building Dbrij Projects and Resikonet Taught Me About Trust

Fintech · 6 min read

Escrow Engines in Practice: What Building Dbrij Projects and Resikonet Taught Me About Trust

Olatunde Success on designing escrow-backed transactions twice, for Dbrij’s milestone-funded project management and Resikonet’s rental platform, and the engineering patterns that make escrow trustworthy.

Idempotency Keys: The Cheapest Insurance in Money-Movement APIs

NestJS · 5 min read

Idempotency Keys: The Cheapest Insurance in Money-Movement APIs

A practical guide by Olatunde Success to implementing idempotency keys in NestJS payment APIs: request hashing, response replay, race handling, and the failure modes that make them mandatory in fintech.

From Ajo to API: Digitizing Nigerian Thrift Savings with Cirva

Fintech · 6 min read

From Ajo to API: Digitizing Nigerian Thrift Savings with Cirva

Olatunde Success on building Cirva, a cooperative savings (ajo/esusu) platform on NestJS with SafeHaven MFB virtual accounts, Paystack direct debit, and tiered KYC, without breaking the social trust that makes ajo work.

One NestJS Monorepo, Three Fintech Products: How I Structure Dbrij, Cirva, and Resikonet

NestJS · 8 min read

One NestJS Monorepo, Three Fintech Products: How I Structure Dbrij, Cirva, and Resikonet

Olatunde Success walks through the NestJS monorepo architecture powering three production fintech products at SAW Technologies: module boundaries, shared domain libraries, per-product deployments, and the rules that keep one codebase from becoming one big ball of mud.

Integrating Nigerian Payment Rails: NUBAN Virtual Accounts, Direct Debit Mandates, and Card Issuing in Practice

Payments · 9 min read

Integrating Nigerian Payment Rails: NUBAN Virtual Accounts, Direct Debit Mandates, and Card Issuing in Practice

A field guide by Olatunde Success to integrating SafeHaven MFB virtual accounts, Paystack direct-debit mandates, and Sudo Africa card issuing into a production NestJS backend, with the failure modes the documentation does not mention.

Shipping React Native Apps That Work on a ₦40,000 Android Phone

React Native · 7 min read

Shipping React Native Apps That Work on a ₦40,000 Android Phone

Olatunde Success on the performance playbook behind Cirva and PODUS mobile: budgeting for low-end Android devices, cutting startup time, taming bundle size, and designing for expensive data in the Nigerian market.

API Contracts and Schema Validation: How to Stop Shipping Breaking Changes

API Design · 6 min read

API Contracts and Schema Validation: How to Stop Shipping Breaking Changes

Olatunde Success explains the API contract discipline he introduced at Jobfactor and uses across SAW Technologies: schema validation at the boundary, contract checks in CI, and versioning rules that let frontend and backend teams ship independently.

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