SEUN ADESINA/full-stack

Seun AdesinaHi, I'm Seun.

I build fast, accessible web apps for startups and small teams.

I've worked on both the front end and the back end since 2018: React, Next.js and TypeScript, plus Node.js, databases and AWS. Most recently that's the new helloaltra.com (opens in new tab) and League of Building, my own product, live at lobb.dev (opens in new tab). I hand over clean, tested code your team can pick up the next day.

Available for new projects

Around 20–25 hours a week · Remote, from Nottingham, UK

Good fit for

  • A first version of a product, from database to UI
  • APIs and admin tools behind an existing front end
  • Adding features to an existing React, Next.js or Node.js codebase
  • Making a slow or hard-to-use web app fast and accessible
  • Marketing sites that need to load quickly

Replies within two working days

Email me

What I work with

The tools I reach for on most projects.

Front end
  • React
  • Next.js
  • TypeScript
  • Tailwind CSS
  • Zustand
  • TanStack Query
Back end
  • Node.js
  • REST APIs
  • PostgreSQL
  • DynamoDB
  • Auth
  • AWS
Quality
  • Accessibility
  • Performance
  • Jest
  • React Testing Library
  • Playwright
Ship & tools
  • CI
  • Git
  • Figma
  • Claude Code

What people say

1 of 4

“Always available to help, incredibly proficient, hits deadlines without fail, hard working and trustworthy. … I can recommend his services without hesitation.”

Max Jeffrey, CEO
Read it all

“Always available to help, incredibly proficient, hits deadlines without fail, hard working and trustworthy. In my experience, no project is too much trouble, and with Seun you really get a rare entity – someone that can simplify what can be a very complex industry. I can recommend his services without hesitation.”

“… I have had so much positive feedback from friends and family on how great the site looks, and have also sold four books already this week direct from the website. …”

Yemi Adesina, CEO, yemiadesina.com (opens in new tab)
Read it all

“Just thought I'd share something with you about my website. I have had so much positive feedback from friends and family on how great the site looks, and have also sold four books already this week direct from the website. Thanks for making it look so professional!”

“… Seun developed and definitely delivered what I was looking for. It's always a pleasure to work with him. …”

Marcello Di Pierro, Marketing Director
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“I was looking for a Web professional who could create and evolve our companies website. Seun developed and definitely delivered what I was looking for. It's always a pleasure to work with him. I look forward to a great working relationship and friendship with him.”

“… His speed of learning and comprehension of complicated topics is fascinating to observe. …”

Danyil Minenko, Mobile Developer, studied with Seun (LinkedIn recommendation)
Read it all

“I once saw Seun complete a 40 hour assignment in fraction of the time and securing an impressive grade. His speed of learning and comprehension of complicated topics is fascinating to observe. This immense intelligence is accompanied by excellent people skills, the combination of the two makes Seun very special. If Seun was to be applied to a meaningful cause which truly resonates with him then the feats he could achieve have no boundaries.”

100% Job Success · 4.9★ from 4 Upwork reviews · 125 hours (opens in new tab)

Tools I've made

read-back

A skill for Claude Code that reads your request back to you, like a pilot reading back a clearance, before any work starts.

View on GitHub (opens in new tab)

What I've built

Recent work, front end and back end. Three are live, and two are my own products.

League of Building's home page: 'Know your damage before you lock in', with the combo simulator below it showing a damage total.The champions list on a phone: all 173 champions as cards, two to a row.

My own product, live

League of Building

League of Legends players guess at builds, because the numbers are scattered across patch notes and item pages. My own product does the maths for them: pick a champion, put a build together and see the whole combo's damage on the current patch.

Read how I built it

The problem

Players guess at builds. The numbers they need are spread across patch notes and item pages, and they change every patch.

What I built

A workshop with the current patch's champions, items and runes. You put a build together and it runs the whole combo. Where an effect isn't modelled yet, it says so rather than guessing. Behind it sits an API on AWS with its own database, Google sign-in so players can save and share builds, and a job that picks up each new patch and checks its data before it goes live.

What it means for players

The damage maths is tested against numbers I worked out by hand, so the damage you see is right. Over 800 automated tests run before each release, and each new patch's data goes through the same checks before it goes live.

What I did

  • Designed and built the whole product, from the database to the screens
  • Built the API and database behind it, running on AWS
  • Added Google sign-in, so players can save and share their builds
  • Each new patch's data is picked up and checked before it goes live

Role & stack

Full-stack developer (my own product)

  • Next.js
  • TypeScript
  • PostgreSQL
  • AWS

Outcome

Live, on patch 16.20

Over 800 automated tests run before each release.

Try it at lobb.devhttps://lobb.dev (opens in new tab)
Altra's home page: 'Altra is the all-in-one experience and engagement platform designed for modern care services', a Book Demo button and a row of care-group client logos.The same page on a phone, the headline over five lines above the client logos.

Marketing site, social care

Hello Altra

Altra makes a platform for care services, and needed a website that explains it to care groups, families and staff. I built that site, in English and French, with a clear path to book a demo.

Read how I built it

The problem

Altra sells to care groups, but families and care staff read the site too, often on a phone. The site had to make the case to buyers in English and French and stay easy for everyone else to read.

What I built

The current helloaltra.com, the website that presents Altra's platform. It has pages for each group Altra serves, each product area, testimonials, data security and the team's mission, all in English and French, with a link to book a demo. The platform itself is Altra's own.

How I made sure it worked

Accessibility checks on every page, and a mobile layout for each section, so a relative on a phone gets as much from the site as a buyer at a desk.

More screens

What I did

  • Built the current helloaltra.com, the site that presents Altra's platform
  • Pages for each group Altra serves, each product area and data security
  • Every page in English and French, with a link to book a demo
  • Accessibility checks on every page, and a mobile layout for each section

Role & stack

Front-end developer

  • Next.js
  • React

Outcome

English and French, 50+ pages

Buyers and families read it in their own language.

Visit helloaltra.comhttps://helloaltra.com (opens in new tab)
Gumbo's About page: 'Helping people cook more and waste less', beside a tray of roasted pears with a chat bubble asking for ideas for pears and walnuts.The same page on a phone, with the search box in the header.

No longer live, screenshots only

Gumbo

Food goes to waste when people can't think what to cook with it. Gumbo let them type in what's already in the cupboard and find recipes that use it. I built the ingredient search and saved collections.

Read how I built it

The problem

Most recipe sites start with the dish. Gumbo started with the fridge, so the search had to be quick to fill in and forgiving about what you typed.

What I built

As a contract React developer on Gumbo's team, I built the ingredient search, saved collections and the screens around them. I fitted them into the existing codebase rather than rewriting it.

How I made sure it worked

Component tests, TypeScript throughout, and testing on real phones. The product has since closed; these screens are rendered from its code with the back end switched off.

More screens

What I did

  • Built the ingredient search: type what's in the cupboard, get recipes that use it
  • Built saved collections and the screens around them
  • Fitted both into the team's existing codebase rather than rewriting it
  • Component tests, TypeScript throughout, and testing on real phones

Role & stack

Contract React developer

  • Next.js
  • React
  • TypeScript

Outcome

Shipped to production in October 2024

People could search by ingredient and save recipes.

No longer liveThe product has closed; these are screenshots.
Yemi Adesina's author site: his name set large on dark green, 'Author portfolio, 34 books', with buttons to browse on Amazon or explore the books, and an email sign-up.The same page on a phone, with the buttons stacked and a full-width Subscribe button.

Author site, 2026

Yemi Adesina — author site

Yemi Adesina writes on African history, geopolitics and farming, and his 34 books were spread across different stores. I built him one home for all of them, on a small budget, that he runs himself.

Read how I built it

The problem

34 books spread across stores, and no home of his own. Whatever I built, he had to be able to run it.

What I built

A library of every book, from African history to his pig-farming guide, grouped into three themes with links to buy. Readers also get answers to the questions they ask. I built the front end and the back end behind it: the book data, a mailing list readers confirm by email, and a simple admin area so he can add books himself.

How I handed it over

Short written notes and one session showing him how to add a book.

More screens

What I did

  • Designed and built one home for all 34 books, with links to buy each one
  • Grouped the books into three themes, from African history to farming
  • Built the back end: the book data and a mailing list, hosted on AWS
  • Added a simple admin area, and showed him how to add a book

Role & stack

Full-stack developer

  • Next.js
  • TypeScript
  • AWS

Outcome

One home for 34 books

Readers buy direct, and he adds new books without me.

See it at yemiadesina.comhttps://yemiadesina.com (opens in new tab)
OmniStats' Today screen in design: the day's four matches across the top, graded lines as cards, and an open read of 'Match under 9.5 corners' with the verdict, the reasons it could land and the main reason against.Explore on a phone: player cards with shots, fouls and booking lines for Torino v Udinese.

Pre-launch

OmniStats

Football stats are easy to find and hard to read. OmniStats, my own product, grades each line on the day's card against the evidence behind it and sets out the case for and against in plain words.

Read what's planned

Where it's at

It runs every day for me on real fixtures, and I'm checking its picks against results before anything goes public. Behind the screens, a daily data pipeline pulls in fixtures and stats, builds the day's card, refreshes it before kick-off and settles each line against the result the next morning. There's no launch date yet. The screens here are the signed-off designs, not the version running today. I'll write it up properly once it's public, with real results rather than promises.

More screens

What I did

  • Designed and built it end to end, as my own product
  • Built the daily data pipeline that feeds it, with its own database
  • Grades each line on the day's card and settles it against the result
  • Sets out the case for and against in plain words

Role & stack

Full-stack developer (my own product)

  • Next.js
  • TypeScript
  • PostgreSQL

Outcome

Pre-launch

It runs every day on real fixtures while I check its picks against results.

Not public yetAsk me for a preview.

Tell me what you're building.

A few lines is plenty: what you have, what you need and when. I'll reply within two working days.

New build or existing codebase, front end, back end or both. You get tests and short handover notes either way.

Rather email? I'm at seun@omnixenon.com.

CV and references on request.

A few lines is fine. Mention your timeline and any data rules.

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