0101 / 04
Backend & architecture
NestJS and Rust services built on hexagonal architecture. REST, GraphQL, gRPC + mTLS, BullMQ queues, circuit breakers on operator calls.
NestJS · Rust / Axum · GraphQL · gRPC · PostgreSQL · MongoDB
Solid software, payments you can trust.
I'm Romario, a software engineer. I design, ship and run web, mobile and cloud platforms, with one speciality: fintech, from Mobile Money to double-entry ledgers.
- years of practice
- 0+
- products shipped to production
- 0
- countries live on Mobile Money
- 0
DEXCHANGE GROUP✦Wisourcing Agency✦LA-ZONE✦Yello Inc✦DevPhantom✦Xarala✦DEXCHANGE GROUP✦Wisourcing Agency✦LA-ZONE✦Yello Inc✦DevPhantom✦Xarala✦
01 — About
One complete chain, delivered by the same person.
Software engineer for over six years: freelance, agencies in France and Belgium, and today technical lead for DEXCHANGE GROUP's products.
I design, ship and run payment systems and internal platforms: merchant gateway, Mobile Money aggregator, double-entry accounting, centralised identity, storage.
Full-stack TypeScript (NestJS, Next.js, React Native) and Rust, comfortable across the whole chain down to Docker / Kubernetes operations. I also work remotely with clients in France and Belgium.
Scoping, architecture, back, front, mobile, prod — one person.
Domains
Payments & Mobile Money, double-entry ledgers, multi-tenant platforms, consumer mobile apps
Methods
Hexagonal architecture, Nx / Turborepo monorepos, Vitest · Jest · Playwright testing, ADRs
Languages
French (fluent) · English (professional)
Education
Master's in Software Engineering, year 1 (in progress) · BSc in Computer Science, UN-CHK
02 — Expertise
What I do best
04 areas
0202 / 04
Payments & fintech
Merchant gateway, Mobile Money aggregator, double-entry settlement ledger, reconciliation. Mandatory idempotency on anything that moves money, signed webhooks, encrypted API keys.
Wave · Orange Money · MTN · Moov · Stripe · KYC / KYB
0303 / 04
Frontend & mobile
Next.js (App Router) portals, operations back-offices and consumer React Native / Expo apps with over-the-air updates.
Next.js · React · Angular · Expo · Tailwind · shadcn/ui
0404 / 04
Infra & operations
Self-managed Kubernetes cluster in production: ArgoCD GitOps, in-house Helm charts, Vault secrets, Traefik Gateway API, Prometheus monitoring. And the incident handling that comes with it.
Kubernetes · ArgoCD · Helm · Vault · Traefik · Docker
03 — Work
Shipped to production
01 / 10Scroll →
Payment gatewayFlagship
DEXPAY
Signed webhooks · idempotency
Collections and payouts for merchants: Mobile Money and cards, in XOF, XAF and GNF. REST + GraphQL API and a Next.js portal.
NestJS · GraphQL · MongoDB · Next.js
Payment switchFlagship
Dex Payment Core
40 service codes covered
In-house aggregator in Rust: operator connectors, double-entry settlement ledger, reconciliation and treasury.
Rust · Tokio · gRPC / mTLS · PostgreSQL
Mobile appFlagship
Dexchange Transfert
4 countries · OTA updates
Money transfers and bill payments in Senegal, Côte d'Ivoire, Cameroon and Guinea.
Expo · React Native · NestJS · Redis
Financial operations
DexFlow
Transaction reconciliation, treasury and next-day close for the group's flows.
Next.js · NestJS · Prisma · BullMQ
Central identity
DIP
One Dexchange account across every product: OIDC + PKCE, realm as code, GitOps deployment.
Keycloak · Helm · Kubernetes
Storage
DexStore
Internal drive and S3-compatible gateway (SigV4 signing): multi-tenant, quotas, controlled sharing.
Rust / Axum · Next.js · S3
Online fundraising
Jappal
Crowdfunding for French-speaking Africa: Mobile Money contributions through DEXPAY, withdrawals, KYC, risk back-office.
Nx · Next.js · NestJS · PostgreSQL
Notifications
DexNotify
Multi-tenant push notification platform, designed as a sellable product.
NestJS · MongoDB · BullMQ · Keycloak
KYC / KYB
DVerify
Identity verification flows for individuals and businesses, with a B2B dashboard.
Next.js · NestJS · MongoDB
Health app
CYLA
Menstrual cycle tracking mobile app, built for the Senegalese market.
Expo · React Native · PostgreSQL
04 — Journey
Six years,
one common thread
Freelance, agencies in France and Belgium, fintech products in Dakar: always close to production.
Download the full CV (FR) ↓Download the full CV (FR) ↓Education
Master's — Software Engineering
Year 1, in progress
BSc in Computer Science — Application Development
Université numérique Cheikh Hamidou Kane · 2021 – 2024
UI Designer track
Programme Tech — Sonatel · 2022
2022 — present
Dakar, Senegal
Lead software engineer
DEXCHANGE GROUP
- Technical lead for the group's products: architecture, security, operations and team leadership.
- Designed and run DEXPAY, Dex Payment Core, Dexchange Transfert and the internal platforms.
- Self-managed Kubernetes cluster in production, incident handling and data migrations.
TypeScript · NestJS · Next.js · React Native · Rust · Kubernetes
Dec 2025 — present
Belgium · remote
Full-stack developer
Wisourcing Agency
- Business applications for the agency's clients: Angular front-ends and NestJS GraphQL APIs.
- Data and GraphQL schema modelling on PostgreSQL, in a distributed Belgium / Senegal team.
Angular · NestJS · GraphQL · PostgreSQL
Nov 2025 — Jun 2026
France · remote
Full-stack e-commerce developer
LA-ZONE
- Headless store: Medusa commerce back-end (catalogue, cart, orders), Next.js storefront and Strapi editorial content.
Medusa · Strapi · Next.js
Nov 2024 — Jun 2025
Hybrid
Back-end developer
Yello Inc
- NestJS back-end services on MongoDB, designing the REST and GraphQL APIs used by client apps.
NestJS · MongoDB · REST · GraphQL
Nov 2023 — Nov 2024
Île-de-France · remote
Front-end developer
DevPhantom
- Next.js / TypeScript interfaces, Tailwind CSS and shadcn/ui design system, server-side rendering optimisation.
Next.js · Tailwind CSS · shadcn/ui
Aug — Oct 2023
Dakar
Full-stack developer & mentor
Xarala
- Next.js / Material UI platform and Django services on PostgreSQL; mentoring junior developers.
Next.js · Django · PostgreSQL · GraphQL
05 — Stack
My toolbox
- LanguagesTypeScript · JavaScript · Rust · Python · SQL
- BackendNestJS · Express · GraphQL · Axum / Tokio · Prisma · SQLx
- Front & mobileNext.js · React · Angular · React Native / Expo · Tailwind
- DataPostgreSQL · MongoDB · MySQL · Redis · BullMQ
- Infra & cloudKubernetes · Docker · ArgoCD · Vault · AWS · Google Cloud
- SecurityOAuth2 / OIDC (Keycloak) · JWT · secrets encryption · KYC / KYB
06 — Contact
Got a projectin mind?
Payments, platform or mobile app — let's talk.