René Weteling

CV - René Weteling
Freelance | Tech lead | Fractional CTO | Problem solver | Full-Stack development
Naam René Weteling
Adres Johannes Geradtsweg 47, 1222PM Hilversum
Telefoonnummer +316 (0) 55 128 199
Portfolio www.weteling.com
E-mailadres rene@weteling.com
Geboortedatum 04-12-1986
Geboorteplaats Capelle a/d IJssel
Nationaliteit Nederlands
## Over mij
Van jongs af aan ben ik altijd geïnteresseerd geweest in computers, scripting en automatiseren. Dit begon toen ik klein
was met het maken van menu's in MS-Dos, gevolgd door zakgeldberekeningen in Works Sheets, en later het bouwen van
een digitaal roostersysteem voor de pizzeria waar ik werkte toen ik 16 was. Logischerwijs heb ik dit pad voortgezet en ben
informatica gaan studeren, waarna ik bij een design agency terechtkwam.
Het leuke aan het werken bij een design agency is dat je projectmatig werkt en met veel verschillende aspecten van IT in
aanraking komt. Dit voedt mijn brede interesse: van teamdynamiek en programmeren tot devops en advies; ik doe het
allemaal graag.
Maar de echte sprong in mijn ontwikkeling kwam toen ik ben gaan freelancen. De verantwoordelijkheid die je voelt voor
een project zorgt ervoor dat je scherp bent en wilt presteren. En deze mindset is uniform voor freelancers, je pusht elkaar
echt naar een hoger niveau.
## Vaardigheden & Kennis
Hier heb ik mijn meest prominente vaardigheden uitgeschreven.
## Talen & Frameworks
De Nederlandse taal
De Engelse taal
Elixir (Phoenix)
Ruby (Ruby on Rails, Sinatra)
Javascript (ES6, Typescript)
Python (vooral nog hobby, maar zou er graag meer mee doen)
Front-end frameworks (NextJs, Swagger, Oas, VueJs, Pinia, Ionic, React, Turbo, Stimulus)
Databases (MySQL, PostgreSQL PgVector, SQLite, MSSql)
Message queues (Kafka, RabbitMQ, Redis)
NoSQL databases (MongoDB, PouchDb, DynamoDB, Redis, ElasticSearch)
Styling (Sass, Scss, Less, Css)
Git flavors (Github, Bitbucket, Gitlab, Azure DevOps)
Projectmanagement (Scrum, Agile, Clubhouse, Flow, Asana, ClickUp, Jira, Azure DevOps, etc.)
DevOps

Terraform (AWS-flavor)
Hosting platforms (Heroku, Dokku, Docker, AWS, K8s, GCloud, Azure)
AWS (Fargate, S3, Route53, Beanstalk, EC2, RDS, ECR, etc.)
CI/CD (Github Actions, Gitlab, CircleCi, Travis)
Architectuur en ontwerpprincipes
C4 model architectuurontwerp
Reactive programming
Gedistribueerde high-load applicaties
Ai
Agent teams inrichten
## Skills ontwerpen
Prompt engineering
Integratie met systemen
Educatie
The Coding Gnome 2019 Elixir for programmers
Bureau Spraakwater 2018 Cursus spreken in het openbaar
Hogeschool Rotterdam 2004 - 2010 Bsc, ICT
IJsselcollege 1999 - 2004 Havo, Natuur en Techniek

## Werk, projecten en ervaringen
Lektor B.V.
Technical lead
01-02-2026 - Heden
Leading the (re)build of Lektor.nl, taking the strongest elements of the current platform
and re-architecting them into a future-proof, scalable system. The focus is on creating a
flexible foundation that enables new product ambitions while remaining robust under
growing demand.
Responsible for technical direction, architecture decisions, and implementation using
Next.js, Zenstack, Zod, and shadcn/ui — building a modern, maintainable SaaS platform
designed for long-term evolution.
Bravoure B.V.
Interim Technical director
## 01-08-2025 - 30-11-2025
Bravoure is a digital agency focused on crafting pixel-perfect, impactful digital
experiences for well-known clients.
More about Bravoure
When the team ran into capacity challenges and decided to separate development from
strategy and design, I stepped in to help drive that transition. I managed the process,
help solve acute delivery challenges, set up practical processes that stick, and provide
hands-on technical direction for new and existing projects.
WAT.WORKS - Beschikbaarheidswijzer.nl
Principal Developer
01-02-2025 - Heden
I support Wat Works as a part-time technical coach, helping their internal team design
and set up a production-ready SaaS platform. Drawing on 20 years of experience, I guide
the initial architecture, coach developers on modern practices, and provide hands-on
feedback — focusing on building a team that can sustainably develop and evolve the
product themselves.
Truely Travel eSim
Sr. Elixir developer
## 01-10-2025 - 20-02-2026
Truely is a quickly growing e-SIM company, providing connectivity for people on the go.
The backend is written in Phoenix, and this is where I come in. Helping out with
fortifying the code-base, building new features, optimizing flows etc etc.
TommyTomato
Delivering healthy hot school lunches
## 12-04-2024 - 17-08-2024
TommyTomato has a mission to turn all children into lifelong vegetable eaters. Plant a
seed, harvest a healthy generation. They achieve this by bringing healthy, hot, and above
all tasty lunches to schools. This involves a considerable amount of logistics; all lunches
must be delivered hot and on time.
TommyTomato is growing rapidly, so much so that the current IT landscape cannot
handle this demand. That's where I come in.
From a Ruby monolith with performance issues, we are transitioning to a monolith
prepared for a reactive event-based services structure, with the ultimate goal of
rewriting everything into Python microservices driven by a queue (Kafka).
My tasks include making the Rails app future-proof, rewriting it into a services
architecture, setting up CI/CD, deploying pipelines, and setting up AWS infrastructure
with Terraform. And many more things.
Beam
Integrating gaming with blockchain
## 01-08-2024 - 31-07-2025
Beam is a blockchain platform focused on supporting a diverse ecosystem of projects
spanning gaming, AI, and decentralized finance (DeFi). The platform features a Layer 1
blockchain secured by Beam Nodes, and incentivizes participation through staking and
validation rewards, resulting in a thriving community of developers, users, and projects.
As Head of Engineering, I led a team encompassing engineers, DevOps, QA, and support,
prioritizing rapid iteration on new concepts driven by emerging market and community
opportunities. This involved periods of intense activity followed by periods of rest. While
the team was comprised of both senior and junior engineers, already possessing strong
best practices, my role focused on providing guidance where necessary, removing
unnecessary constraints, coordinating with stakeholders on design and rollout plans,
and maintaining team morale and motivation. This was an exceptionally rewarding and
enjoyable assignment.
Semmie.nl
Asset management simplified
## 02-10-2023 - 11-04-2024
Semmie is an asset manager where clients can easily open an account. Through a smart
questionnaire, the associated risk profile is determined, and Semmie actively manages
the investments. Clients can control everything through the app or online portal.
Semmie also offers the option for advisors to set up all of this through the advisor
portal.
In the vast landscape of Semmie's tech infrastructure, I find my focus within the
intricate layers of the CRM backend, API, (Mobile) App, and Advisor portal – essentially,
the tech heartbeat of our operation. My current playground is the backend, where I'm
actively shaping and enhancing features for the Rails API and App. Simultaneously, I'm
deeply immersed in setting up DevOps resources, collaborating seamlessly with Azure.
Addressing the historical separation between the frontend and backend teams, my goal
is to close the gap, encouraging cross-functional collaboration, and ultimately forging a
cohesive, unified team. Let's seamlessly merge these tech realms into a singular,
synergistic force.
Odido / T-Mobile
TSC - Business router gui's
## 01-11-2021 - 28-09-2023
Odido, formerly known as T-Mobile, has a digital realm that extends beyond what meets
the eye. As a developer in the company, I have the opportunity to think like an architect,
considering responsibilities, data storage, and optimal placement. It's an engaging and
enriching experience.
I am currently a member of the Red team in the Operational Support Services
department, consisting of three RGB teams. Our primary focus is to create, manage, and
support operational services to ensure the seamless functioning of our entire service
portfolio. With over 18 applications to oversee, ranging from Node.js and Ruby on Rails
to Elixir and Bash scripting, my team plays a critical role in maintaining their
uninterrupted operation.

## DPG
Media backbone for media outlets
## 01-11-2019 - 29-10-2021
MyChannels is a division within DPG Media group that is responsible for all digital
content on all digital outlets of DPG. Ad.nl, Volkskrant.nl, Hln.be, Trouw.nl, Parool.nl and
so on. The team is compact, senior and knowledgeable. We are responsible for more
than 5 million video plays each day. Creating services to supply the media outlets with
videos, games and entertainment. Providing the mobile API for the apps of the papers.
And so on.
More about DPG and MyChannels
As a full-stack developer I've worked on the backend, mainly in Phoenix and Ruby on
Rails, created new interfaces inside of the videoplayer using React, Svelte and
Typescript. Changed styling for new brands. Added schema changes. In the last 6
months my focus was on infrastructure, moving from manually created infra to
Terraform, implementing security best practices and making the whole infra more
robust and flexible.
Re:turnista
Parcel return software
## 01-02-2019 - 28-02-2019
Re:turnista is an app where clients of webshops can return items they bought. Using a
mobile first app, the user is guided through a couple of questions and the package is
ready for pickup.
The actual app is available here
As a full-stack dev, I was tasked to give the current architecture some love to make it
more performant. We removed all the custom form logic and implemented a package
called Formik, changed the event structure to work more with reducers. Overall cleanup
and modularizing of the system.
Zwitserleven
Client portal for pensions
## 01-03-2019 - 31-03-2019
Vivat is the mother company of Zwitserleven. Vivat has a "My" environment where
clients can log in and see information about their products. My team was responsible for
the Pension funnel.
More about zwitserleven and The Main Ingredient
As a front-end developer, I changed the loading system (basically the system contained
multiple systems so a dynamic loader was needed, especially with varying backend
services). Created small updates, and fixed some tickets.
DigiB
Chemical e-trading system
## 01-04-2019 - 31-10-2019
DigiB is a division of Brenntag. Brenntag is market leader in the supply of raw chemicals.
DigiB is tasked with the digital transformation of Brenntag by bringing an e-commerce
system, internal trading and couplings between all offices.
More about DigiB
As a front-end developer I've worked with the front-end team to expand the ecommerce system built in React, with Next.js and a Node.js middleware. I've also been
working on the "target architecture", an overcoupling system that is able to connect
multiple ERP systems like Oracle, SAP, Salesforce etc. This design was Reactive using a
message bus.
Ace & Tate
Backend ecommerce system
## 28-05-2018 - 31-01-2019
Ace & Tate sells glasses online and offline, they have "currently" over 30 stores world
wide and they use an e-commerce platform (Solidus) to process all orders. Since the
company continues to change, the backend also needs to be quite versatile.
More info about Ace & Tate
As a full-stack dev, I was tasked to optimize and add features to the Solidus powered
Ruby on Rails backend. For the consumer and POS facing this was mostly an API. For the
internals there was an Admin section and for the internal Friends and Family there was
a complete suite with admin panel implemented. I helped maintain over 30 gems, used
Elastic Beanstalk for running the app, and increased the test coverage overall.
Tankey
Admin interface including API for gasoline loyalty program
## 22-01-2018 - 27-04-2018
Tankey is a loyalty platform (LP) created by Essent for their other brand EnergieDirect.
The first version of the LP was built within Essent. Meaning that linking other companies
proved to be difficult, that's why they split up Tankey from Essent and started building a
new and better version of the app.
More info about Tankey
As a backend developer I was tasked to build an API for the Tankey Android app, build an
admin interface where the business can see KPIs, create exports and get the correct
insights in what the app is doing. Build a stable and auditable system concerning the
new GDPR ruling. Create API couplings between Firebase for in-app notifications. Create
a discount calculator module. And integrate loyalty partners through our API.
Abn Amro
Cybersecurity awareness app
## 04-12-2017 - 25-01-2018
The Main Ingredient was tasked to help out the CyberSecurity department of ABN Amro
with creating more awareness for cyber threats for small companies. Think of phishing
emails, certain new techniques that they have spotted or even social engineering. TMI
came up with Veiligzondermoeite.nl, an initiative to inform the general public.
More about Veiligzondermoeite and TMI
As a full-stack developer, I was asked to lead a team of highly skilled developers and
designers to create in just 6 weeks a working POC of the app. The app was built in
ReactNative, the backend in Node.js using Express as server layer and deployed on
BeanStalk using a CloudFormation template. We also hooked up an RDS instance for our
persistence. My main focus was in creating the backend and helping out with the
ReactNative app. The team was excellent in styling / creating components, my
assistance was most needed in hooking up the APIs.
BotSquad
React - Webpack - Jekyll
## 16-10-2017 - 17-11-2017
With the BotSquad bot, you can create bots for the web, mobile and chat interfaces like
facebook, slack, twitter etc. There is a beautiful studio where you can create bots using a
friendly and semantic DSL. And preview the bot in real time.
React coding on the Chat client
Creating the API
RnD on the bot itself
Adding features

HalloRoos - SNS experiment
Rails - Roos API - Heroku
## 11-10-2017 - 08-11-2017
HalloRoos is a contract alarm platform where users can set alarms for contracts that
will expire in the future so that they can switch providers on time. HalloRoos was
looking to extend their functionality and needed a developer to help them reach their
goals. The subject itself is somewhat sensitive, but it comes down to a pretty selection
then order flow with alot of validations and constraints. Each step is communicated to
an API provided to store and manage the data.
Build the pages as described in Rails using Slim, Sass, and CoffeeScript
Connect the pages to virtual models so that we can apply validations
Persist the validated models to the provided API
Van Ons B.V. - Carpet App
React - LibVips - OpenVc - DeepZoom
## 02-06-2017 - 13-09-2017
Van Ons is a really cool WP design agency based in Amsterdam. For some projects, they
contract out for special features and this was quite special. They wanted to create a web
interface were clients can cut out a portion of a really big image (30 by 30 meters at 76
dpi approx 46GB per image). So I've developed a React frontend where the users can
walk through the image using DeepZoom. And cut out a shape and then sending the
coordinates to a worker server, cutting out the piece and mailing it to a carpet printer.
Pretty heavy stuff.
Everything was new, everything was exciting, it was an awesome project. The final
version is visible here at Skonne
Build a react app to define the area that needs to be sliced
Create a slice worker server that slices the image according to the dimensions provided
by the react app
Figuring out how to slice images as big as 46GB each
Revolve Music
CTO - Rails - AWS - CI - rSpec
## 03-04-2016 - 15-09-2017
Revolve Music is a SAAS platform where users (Artists mostly) can create a website, a
digital presence in just a few minutes. Connecting to filled content providers like
SoundCloud, BandsInTown, LinkedIn, Twitter etc your site is filled with content and you
are ready to go.
Clean up and rebuild existing code (the overall quality was very poor and not very robust)
Create a Continuous integration environment using CircleCi and AWS container service
Creating a global scaling web server setup using: Route53, AWS EC2, AWS EC2 container
service, Cloudfront, RDS, S3 and Docker
Being responsible for the Technical day2day, building team culture, applying standards,
laying out technical roadmaps etc. CTO stuff.
Leaplines
Onboarding software for large companies
## 01-05-2015 - 01-02-2016
Leaplines is a SaaS that helps companies with their on-boarding process. Providing a
curriculum based on the employee's role within the company, with a clear hierarchical
method of stimulating the users through there managers.
We made use of the following: Rails, PostgresSQL, CircleCI, Github, Rspec with Capybara
( TDD ), jQuery, React, Rails UJS
Going to clients, getting feedback from the source
Building new features, mainly onboarding exercises in for form of a game
Scrum plannings etc
Horyon innovaties B.V.
Android process app, Rails backend
## 15-10-2015 - 01-09-2022
Horyon innovaties B.V. is an asbestos removal company. Asbestos has a bad reputation
and that's why there is a lot of legislation. They are required to have all data on premise
at all times. This is just not possible on paper, so we have created a Rails backend with a
Restful api connecting an Cordova Android app. The app started out as a simple hour
measuring platform, but now it has over 18 main functions and one of them is drawing
on a photographed map.
Design the product matching the needs of the business
Creating a Rails backend, with role based authorisation
Ops: it runs on my own High availability cluster powered by Flynn.io
Creating the React Cordova android app
Click.nl - employed
iOS, cordova and react development
## 01-07-2012 - 01-04-2015
Coming back to click felt really good. They had so much faith in me that they wanted to
set up a new office in Amsterdam with the main focus on Mobile. We had some really
great clients. We have build an app for KPN where users can view the last goals in a
soccer league. Build an app for a recruitment agency and many more.
Overstappen.nl - employed
Symphony - Php - Less
## 01-08-2011 - 01-07-2012
This is the first time i got in contact with a proper framework. Symphony. It's mature, it
has a rich plugin ecosystem, its consistent. I liked it allot. Learned a lot here, the main
issue was that i was the only dev in the company so i got a bit bored and moved on.
Great experience though.
Click.nl - internship then employed
Perl - CaretCMS - Scripting - Discovering
## 01-12-2008 - 01-08-2011
My internship at Click.nl was great, a young team, cool founders, nice environment and
Dirk the dog. I've learned so much here, multiple languages, dynamics in the company's
themselves. Learned about budgets, stakeholders, planning etc. It was a great
## experience.