Hello! Im Matheus Mendes and im a software engineer

Things I've worked on

Midjourney

Making images look good

Work

Dema

Analytics platform for E-commerce

Work

vercel-ui

Design library inspired by Vercels design system

TypeScript
24
91

Sideproject

css-only-rubiks-cube

A spinning Rubik's Cube with functionality all made with CSS only

CSS
10
21

Sideproject

lucio

TLDR; Leetcode and CSS Battles into one platform

TypeScript
16
341

Sideproject

Acasting.se

Modern casting platform

Work

About me

I am a full-stack developer with experience in web applications and apps.

Currently I work as a software engineer at @Midjourney

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headshot

First line of code

First software engineering job

Total prod crashes

1 oops :(

Rank #1000 on CSS Battles

I really like CSS (I don't really get the hate), and one of my favorite sites is CSS Battles where you can compete with CSS. I used to play it a lot and at one point I got to rank 800, but now im sitting at around 1000. There is about 350k total users on the platform.

headshot

Matheus Mendes

53700.24 points
(84 Targets)
#1146
Tetris css battles

Rank #36 in the world

Tetris css battles

Rank #74 in the world

Tetris css battles

Rank #36 in the world

Tetris css battles

Rank #38 in the world

Tetris css battles

Rank #52 in the world

Tetris css battles

Rank #62 in the world

Tetris css battles

Rank #86 in the world

Tetris css battles

Rank #74 in the world

3413 total github contributions in the last year

Midjourney

Midjourney

Software engineer, February 2025 - Now

Company update polaroid

Dema.ai

Software engineer, April 2023 - February 2025

  • Full-stack ownership of the web-app (core product).
    • Owned internal state management with Jotai
    • Led and developed a Product Segmentation feature on my own that single-handedly secured multiple clients. This featured handles and labels tens-of-thousands of products per day. See it here
    • Developed our Marketing Mix Model feature on the application side. See it here
    • Migrated legacy SASS components to custom Chakra UI (moral of the story, chakra is a mistake, just use tailwind)
    • Worked on dashboards
    • Worked on teams and role-based access control
  • Owned and wrote almost all of the changelogs, See it here
  • Built our Shopify integration handling all order and inventory data for our Shopify customers. Later, I created a monorepo for all our other e-commerce integrations, saving multiple hours of dev-time for our engineers. Used Turborepo and deployed it to K8s
  • Bought a Polaroid camera on my very first day, which has taken well over 300 pictures and has been a core part of the internal employee branding. I also took it one step further on my 1-year anniversary and created a custom page with all Polaroids. See it here

Live site

Dema (the company I work at) is an analytis platform for e-commerce that help companies understand there profitably. Its a very cool platform and down below is a small replica I made to showcase sort of how it looks but also some things you can do. Of course there is A LOT more to the platform than what is down below:)

Dashboard
Reports

Starting view

Show compare

Channel
Channel group
Visits
Sales
Instagram
Meta

7,645

17.62%

567

18.37%

Facebook
Meta

5,123

6.73%

423

5.49%

Google Ads
Google

3,137

8.17%

289

17.96%

YouTube
Google

2,123

17.94%

178

14.10%

TikTok
ByteDance

4,567

42.72%

345

20.21%

LinkedIn
Microsoft

1,567

11.93%

134

19.64%

Twitter
Twitter

2,567

11.61%

201

6.35%

Pinterest
Pinterest

1,267

15.18%

98

15.29%

Snapchat
Snap Inc.

3,567

15.06%

267

14.10%

Email
Direct

4,567

8.74%

389

9.27%

Organic Search
SEO

6,567

13.22%

512

7.11%

WhatsApp
Meta

2,345

11.67%

187

13.33%

Bing Ads
Microsoft

987

16.12%

76

22.58%

Reddit
Reddit

1,876

17.25%

143

11.72%

Quora
Quora

765

9.29%

54

12.50%

Display Ads
Google

3,456

8.00%

278

9.45%

Affiliate
Partners

2,345

17.25%

198

12.50%

Referral
Partnerships

1,234

12.18%

98

12.64%

Direct
Direct

5,678

9.19%

467

10.40%

Podcast Ads
Audio

876

16.80%

65

20.37%

SMS
Direct

1,543

10.21%

132

11.86%

Push Notifications
Mobile

2,109

11.00%

176

10.69%

Webinars
Events

987

16.12%

87

19.18%

Lovable

Part-time consultant, November 2024


Built their landing page over a couple days while i was solo traveling in Thailand. This was part of their rebrand for their third launch, which happened to make them the fastest growing company in Europe ever.

Matheus profile image

Lovable

@lovable_dev

Building products takes too long. We started Lovable to fix this.

Today, we`'re officially launching the world`'s first AI Full Stack Engineer

Lovable reliably replicates the capabilities of a full stack engineer and handles everything from design to database operations by integrating with Supabase.

So what`'s new exactly? 🧵
73
142
642
759

CSS only Rubiks cube

October 2022

The project below was made with a total of ZERO lines of Javascript, its all just CSS. Every animation, hover effect and button click is just a combination of some clever CSS code.

I made this because a friend told me it was not possible to do, so out of spite, I had to prove him wrong. Thats also why if you look very closely in the bakgrund of the real website there is a lot "L"s in the bakgrund

Repository
Live site

Vercel UI

Creator and sole maintainer, 2024

Design library inspired by Vercels design system. It's the same concept as ShadcnUI but does tackle some issue I felt ShadcnUI skips over, like handling multi-part components with multiple different sizes for example.

Repository Live site
graygray-subtlebluepink-subtlegreengreen-subtletealteal-subtleblue-subtlepurplepurple-subtlegraygray-subtleblueblue-subtlepurplepurple-subtleamberamber-subtleredred-subtlepinkamberamber-subtleredred-subtlepinkpink-subtlegreengreen-subtletealteal-subtle
npm init next-app
Blue
Matheus
Is this red?
Vaaarning
npm init next-app
npm init next-app
Blue
Matheus
Is this red?
Vaaarning
npm init next-app
npm init next-app
Blue
Matheus
Is this red?
Vaaarning
npm init next-app

Professional Overwatch Player Overwatch

2017 - 2020

  • I was consistently in the top #500 rankings for europe on playstation with multiple different accounts, peking at top #30 at points.
  • Competed for the scandinavian team in the world cups for Playstation
  • For certain heroes I was in the top #100 for and peaked #7 for Winston at a certain point.
  • I was 13-16 years old btw

Acasting.se

First software engineer, part-time consultant, November 2023 - March 2024

  • Built out the entire app, end to end, together with another engineer, and launched the first version in a single month
  • Scaled from 0 to 20k users
  • Was involved in all technical decisions
  • Handled billions of row reads, and millions of row writes
  • Developed a custom in-house chat to reduce our monthly costs by over $500/month
  • Worked on our recommendation engine
  • Implemented mobile design and responsiveness
  • Introduced our location feature, helping 100s of casters find amongst 1000+ locations (very similar to Airbnb)

Live site

LucioCode

April - Mars 2021

TLDR; It's Leetcode and CSS battles combined into one that I made in early 2021 for fun. This project also landed me my first job as a software engineer, so it holds a special place in my heart.

Repository
Live site

Simple addition

Easy

Given two integers, a and b, return the sum of a + b

Sample Input

a = 5 
b = 7

Sample Output

12

Explanation

The sum of of 5 + 7 is 12

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