Mattias Björklund
Verified Expert in Engineering
Full-stack Developer
Stockholm, Sweden
Toptal member since October 3, 2022
Mattias is an accomplished professional with nearly a decade of experience working as a full-stack developer on diverse projects. His background includes freelancing and working for large companies, such as Spotify, providing impactful contributions as a valued team member. Mattias is eager to take on new challenges and deliver results by combining his skills and enthusiasm.
Portfolio
Experience
- Software Development - 10 years
- Python - 8 years
- Django - 8 years
- Python Asyncio - 6 years
- TypeScript - 5 years
- React - 5 years
- Google Cloud Platform (GCP) - 5 years
- Next.js - 3 years
Availability
Preferred Environment
OS X, PyCharm, WebStorm, Git, Docker, Vim Text Editor, Amazon Web Services (AWS), Google Cloud Platform (GCP), Full-stack, Front-end Development, Front-end, Architecture
The most amazing...
...tool I've developed is Fanbase, the Spotify user administration tool used by 2,000+ customer service agents to get the power of 50+ APIs.
Work Experience
Freelance Software Developer
Efuel
- Built a full-fledged eCommerce site for buying charging stations and accessories with installation for electric vehicles. It's a Next.js site with a NestJS back end built on top of Shopify APIs and Strapi CMS.
- Built a data pipeline based on webhooks, PubSub, and NestJS for getting all incoming eCom Shopify orders into a Fortnox accounting and invoicing system—shuffling several million dollars per month.
- Joined the team to help them complete the long overdue migration of a wholesale eCommerce site from a Shopify template site to an entirely custom Next.js site.
- Evolved the team I joined from green to mature by successfully promoting a new WoW with an entire scrum board restructure, PRs with reviews, walk-the-board stand-ups, and more.
Acting Staff Engineer
Spotify
- Managed the tech needs for the customer support tooling for the pilot that Spotify payments did with Google to enable in-app payments through the Google Play billing system.
- Integrated a fully-fledged, Spotify proprietary user behavior tracking system into Spotify's support site to enable user tracking across all apps and sites, allowing a much-improved support experience for end users.
- Closed down and migrated the last and most tedious features of Spotify's 9-year-old previous user administration tool.
Senior Full-stack Developer
Spotify
- Developed a user administration tool used by thousands of customer service advisors to investigate and solve any customer issue, replacing a seven-year-old tool with a new modern and fully fledged web app.
- Built the integration between the new CMS system and Smartling to efficiently export support articles for translation and import them into over 20 languages.
- Ensured a successful conversion from a non-GDPR-compliant user administration tool into a fully encrypted and compliant one, rewriting thousands of lines of code and migrating billions of rows of SQL data.
Full-stack Developer
Bambora AB
- Built a loan administration tool for a successful pilot to be brought to the next level, allowing many more customers (merchants) to cash out a loan with their future card income as security and downpayment.
- Iterated on the loan administration tool, closely collaborating with internal users to optimize the tool for their workflows and to enable merchants to monitor the status of the loan and their daily downpayment.
- Oversaw and managed microservices with databases with multi-billion rows of essentially card transaction data, enabling merchant customers to smoothly browse their transaction data while still maintaining system scalability.
Senior Back-end Developer
Bumbee Labs
- Drove the back-end system from a proof of concept (POC) to a scalable microservice system that could handle thousands of nodes, sniffing WiFi signals from millions of devices daily.
- Triangulated positions and stored paths in PostGIS, enabling querying by a polygon to get statistics on paths crossing the polygon.
- Built a Django web app to assist the data scientists with calibrating the measurements and building reports for customers.
Experience
Housing Associations Info Screen
It is built with Vue.js and Django Channels and uses a WebSocket to keep data transfers at a minimum and instant orchestration. It is deployed on DigitalOcean using Docker, version-controlled using Git, tested using CircleCI, and monitored using Sentry and a custom alerting service.
The project is live but available to authorized users only: https://homescreens.se/.
Spotify User Administration Tool
The scale of the tech infrastructure of the company and the enormous amounts of accounts put heavy requirements on the application's architecture. For this reason, the web client was communicating with the back end using a long-lasting WebSocket, enabling an efficient caching strategy and tiny request-response cycles.
The project was a spin-off from my hack week project, where I made a POC to show how major problems with the existing solution could be avoided.
Education
Master's Degree in Mechatronics
KTH Royal Institute of Technology - Stockholm, Sweden
Skills
Libraries/APIs
MobX, Python Asyncio, React, REST APIs, Spotify API, Vue, Protobuf, jQuery, Node.js, D3.js, Carbon, Pandas
Tools
PyCharm, WebStorm, Git, MATLAB, NGINX, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), Celery, Vim Text Editor, BigQuery, RabbitMQ, Pytest, Terraform
Languages
Python, TypeScript, CSS, JavaScript, HTML, SQL, ECMAScript (ES6), C++, C, Lua, GraphQL
Frameworks
Django, Next.js, Jest, Flask, Django Channels, Django REST Framework, gRPC, Starlette, NestJS, Swagger, Tailwind CSS
Paradigms
REST, Unit Testing, Microservices
Storage
PostgreSQL, Redis, PostGIS, MongoDB, NoSQL, MySQL, BigTable
Platforms
OS X, Docker, Google Cloud Platform (GCP), Amazon Web Services (AWS), Shopify, Heroku, Algolia, Kubernetes, DigitalOcean, Firebase
Other
Software Development, Mathematics, Numerical Analysis, WebSockets, Back-end, APIs, Full-stack, Front-end Development, Front-end, Architecture, Electronics, Physics, Product Development, Pub/Sub, User Experience (UX), User Interface (UI), Technical Leadership, Data Analysis, Data Scraping, FastAPI, WiFi, Statistics, Strapi, Argo CD, Platforms, User Behavior, Quantitative User Research, Online Payments, Business Loans, Web Scraping, Scraping, Fintech, Single Sign-on (SSO)
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