Backend developer and DevOps consultant. I write the services, and I run the Kubernetes clusters they live on.

Samuel Assemien

Abidjan05°19′N 04°01′W

Available for contracts

01Manifesto

The expensive bug doesn’t take the service down. It answers “OK” when nothing actually happened.

I spend as much time on what happens when things fail as on the path that works.

02Selected work

03Backend and architecture

Code someone can pick up in two years

NestJS
Fastify
TypeScript
Prisma
PostgreSQL
Redis
BullMQ
Keycloak

A modular monolith, internal events rather than cross-calls, one data access layer. I draw the PostgreSQL schema before writing a line. One example of what that buys you: a Prisma connection pool that kept running dry under load, fixed by putting PgBouncer in front in transaction mode instead of making the pool bigger.

03DevOps and infrastructure

I build the clusters, and I keep them

Kubernetes
k3s
Helm
ArgoCD
GitLab CI
WireGuard
Harbor
Prometheus

Twenty-five services moved off Docker and Portainer onto a kubeadm cluster in production. With everything that comes with it: multi-realm Keycloak, wildcard certificates over DNS-01, a WireGuard VPN for administration, Trivy, kube-bench and Falco scans. And the two in the morning outages, which are part of the job.

03Payments — specialty

Mobile Money: the hard part comes after the call

available_balance: Withdrawable now
pending_balance: Awaiting settlement
locked_balance: Frozen — dispute or KYC

Orange Money, MTN, Wave, Moov, Airtel. The integration takes a day; the rest of the time goes on non-final states, webhook replay, idempotency by client reference and daily reconciliation. I designed a three-balance wallet so no discrepancy stays unexplained. All of it under BCEAO requirements.

04About

I write the service, and I get the page when it falls over

I started in 2020 in Yamoussoukro, on property and hotel management applications. Since late 2023 most of my work has been payments, and since early 2026 I also look after the infrastructure of a fuel distributor, on a freelance basis.

What suits me in this job is holding both ends. I write the service, I deploy it, and it is my phone that rings when it goes down. That changes how you write logs.

Based in: Abidjan, Côte d'Ivoire
Languages: French, English
Format: Freelance, remote or on site

05A few numbers

6: years of backend development
5: packages published on npm
12: client projects since 2020
4: Kubernetes clusters in production

06Published under @samofprog

Pieces pulled out of real work, published under MIT once they are clean enough to be useful elsewhere. All TypeScript-typed.

@samofprog/corekitShared NestJS utilities — Axios error normalisation, type guards, structured logging helpers.8 /wk
@samofprog/nestjs-logstackDrop-in Winston logger — daily rotation, one file per level, compressed archives, JSON in production.14 /wk
@samofprog/nestjs-password-validatorDecorator-based password validation — composable rules, blacklist, confirmation field.11 /wk
@samofprog/nestjs-request-loggerHTTP logging middleware for NestJS — sensitive header masking, path exclusion, zero external dependencies, works with Express and Fastify.39 /wk
@samofprog/tiptap-vuetify-nuxtNuxt port of the Tiptap rich-text editor for Vuetify.6 /wk

07Let's talk about your next project

sa.assemien@gmail.com

Backend development, taking over or setting up an infrastructure, auditing an existing payment integration. Write to me and I answer the same day.

Samuel AssemienSamuelAssemien