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nassdaq — Kelvin Oscar Mwaijega, software engineer

Illustration — an artist at work
Illustration — code snippets

Software for founders with a vision

I build software that adds an extralayer to everyday work. Backend, web,WhatsApp commerce, dashboards, opensource: five crafts, one vision. What weship together earns a place in theworld. Let us make it useful.

I build software that adds an extra layer to everyday work. Backend, web, WhatsApp commerce, dashboards, open source: five crafts, one vision. What we ship together earns a place in the world. Let us make it useful.Start your project

From idea

Kelvin Mwaijega
Code taking shape on screen

to production

A working desk in the studio
Craft

Five crafts, one vision

Backend systems

What does your product stand on? Not the framework, but the foundation. I start there and let everything else flow from it: the data model, the API, the queues. That way your product becomes the obvious choice.

More about this
API designEvent pipelinesRust & Python

Web apps

People feel quality before they inspect a single line. In a load time, a transition, an empty state. Interface craft is not decoration you add later: it is how your product presents itself to the world. This is how you build something that can be yours alone.

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Next.js & ReactDesign systemsPerformance

WhatsApp commerce

WhatsApp is where your customers already are. Something to tap, to trust, to come back to. The work lies in details people don't always see but do feel: message timing, idempotent payments, graceful retries. This is how your brand stays in their pocket.

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Carts & checkoutPaymentsOrder flows

Data & dashboards

A dashboard is not an “oh yes, we need that too” — it must show how the business breathes. Not a template you fill in. A place where people sense whether the numbers are right or not. I build internal tools that feel familiar from the very first second.

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Admin panelsAnalyticsSession replay

Open source tooling

You ship code every day, in various repos and countless terminals. I build the scaffolds, CLIs and libraries that you reach for every day. This way your stack stays recognizable without starting from scratch every time.

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CLIsScaffoldsLibraries
Kelvin Mwaijega, software engineer, working in Dar es Salaam
about

Who I am

I am Kelvin, and I learned my trade inside real product teams, shipping for names like Neurotech Africa and Tanpanels. I now hold the same standard from my own desk in Dar es Salaam for every founder who understands that software is more than a demo: no half measures, every decision counts.

Read my story
Building alongside a client, screen shared
Approach

How I work

I don’t work for you, but with you. I ship a well-thought-out first version and take you along in the reasoning. No vague sprints here or mystery invoices there. The whole thing has to be right.

Hands on the keyboard, mid-flow
In production

I could tell you all this myself, but the products say it better.

Galacha

Session replay that installs in two lines and stays out of the way.

15KB
SDK
<50ms
overhead
2,000
free sessions / mo
Read case study

GhalaRails

AI support on the WhatsApp Cloud API, with handover the moment it matters.

500+
businesses
<3s
AI response
93%
delivery rate
Read case study

EscrowLipa

Mobile money held in trust until both sides confirm the deal is done.

5+2
payment networks
48h
dispute window
42m
open → released
Read case study

Barua

Business email on the domain a company already owns, DKIM signed.

50,000
emails / month
20
mailboxes
1 GB
per mailbox
Visit the site

Sema

One Tanzanian number, every call captured, routed and transcribed.

SW + EN
transcription
AI
call summaries
TZS
local billing
Read case study

Every figure above is published on the product’s own site.

Toolbox

Proud to run on these tools

Rust, Python, TypeScript, Next.js, React, Ruby on Rails, PostgreSQL, Redis, Docker, Tailwind CSS
WhatsApp Business API, FastAPI, Neon, Vercel, Prisma, GSAP, Framer Motion, Linux, GitHub Actions, Cloudflare
Open source

Things I build in the open

Rows of code on a dark screen

workingdb · Rust

A tiny working database, built from scratch to learn what a database actually is under the hood — pages, a B-tree, a WAL.

A terminal glowing in a dark room

monsterVM · Rust

A small stack virtual machine and bytecode interpreter — a complete little runtime, from the instruction set up.

A laptop open to source code

pasaka-api · Python

A clean, batteries-included API scaffold I reach for to ship backends fast — auth, migrations and tests already wired.