I love enabling you to create great software

Jonas Jabari - Development, consulting, open source and digital product creation
Hey! I'm Jonas
I'm passionate about software development, open source and digital product creation

I love to enable or help others create great software. I help my clients find the right concept and implement applications. Additionally I create open source libraries that fight the complexity of web development.

In my spare time I create digital products and blog about technology and entrepreneurship.

450+ GitHub stars
10 years experience
Based in Germany
German and English
Ruby and JavaScript
Let's succeed together

I'm available for web development and consulting. I'm happy to enrich your existing tech team or help you to conceptualize and create your software by myself or with my partners.

Full stack web development
I'm happy to enrich your existing tech team with my expertise
As a full stack developer, I've already worked alone and in a team, as an employee and as a freelancer. During the last 10 years, I've also managed multiple agile tech teams (up to 4 developers) implementing complex web applications.
I'm available for tech freelancing (short & long term) adding value using...
Ruby
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After originally starting backend development in PHP, a friend introduced me to Ruby, it simply clicked and I've worked with it ever since and never looked back. In the past 7 years I've created, refactored and iterated various complex applications based on Ruby On Rails (versions 4,5 and 6) and created an addon Gem for Rails with >450 Github stars.
JavaScript
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I started to use JavaScript in 2013, when creating my first AngularJS apps. During my master thesis, I've learned node.js as well in order create a predictive maintenance system in an IoT context. After that I picked up Vue.js, which quickly became my go-to for client-side implementation.
HTML/CSS
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Since I learned the basics of HTML and CSS when I was 15, I've used them both in pretty much all of my projects, most often in combination with frameworks like Bootstrap or Material Design.
Postgres/MySQL
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As I'm almost always dealing with data driven applications, I'm using SQL databases a lot. Worked with MySQL as well as with Postgres. Btw: I love to create complex queries with Arel!
CI/CD
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Having worked with the GitLab CI in combination with dockerized applications for around 3 years now, I can only recommend this approach. We're talking Test, Staging and Live enviroments, of course!
Testing
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Perhaps I can't thank those senior software engineers enough for introducing 'junior me' to the concepts of unit and feature tests! These days I mostly use rspec and capybara, which have saved me from mistakes and helped keep my sanity quite often already.
Infrastructure and more
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Even though I'm not the biggest Linux nerd, I've worked with Linux and its terminal since 2013 almost every day. Same applies for server administration via SSH and GIT. Additionally I know how to handle NGINX and loadbalancing, if neccessary on a global distributed infrastructure.
Something new?
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There are just too many great tools out there, so I have to admit: I don't know them all! But I'm super happy to learn new stuff when the time and opportunity calls. Currently I'm looking at Stimulus and React regarding JavaScript technologies and Crystal as a high performance server side language.
Consulting & Product creation
I help you to conceptualize and create your software or product
One of my core strengths is to combine my tech expertise with business insights and requirements. After gaining an understanding of where your business is heading, I help you come up with a concept and map it's requirements to appropriate technical solutions. After doing that, I can either implement the software with my partners or enable your desired tech team to do so!
I'm available for ...
Initial workshop
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You have an idea for a digital product or software and need input how to build it? And probably most importantly: What price range will it be in, roughly? I support you in finding answers to these questions and structure your idea from a technical perspective in a workshop.
Requirements engineering
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Before any project can be turned into software, it's a really good idea to identify and prioritize your requirements and translate them to technical blue prints. Based on my development skills and my own experiences with product creation and entrepreneurship, I'm able to give your project a good start working on your requirments. The resulting documents can be used for a more finetuned price and effort estimation and are supposed to be used as input for the development phase.
MVP implementation
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I always recommend to filter the most important features from the processed requirements and turn them into a working minimum viable product or prototype. It's a great and often very affordable platform to test, learn and figure out what to do next. I'm happy to implement your MVP for you - either alone or with my (or your) partners.
Iteration & growth
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You're happy with the results of your MVP and want to iterate, add features and grow your application? Depending on the size of the scope, I'm able to provide the required implementation together with my partners or onboard your desired tech team. If you want to build your own inhouse tech team, I'm more than happy to onboard and support new developers!
Open source
Sustainable open source projects are a key aspect of today's tech industry
Creating open source libraries, helping others and collaborating with developers around the globe means pure fullfillment for me. After using various open source projects myself, I started to create open source projects myself at the beginning of 2018.
Highlighted open source projects
Matestack
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matestack-ui-core enables you to craft maintainable web UIs in pure Ruby, skipping ERB and HTML. UI code becomes a native and fun part of your Rails app. Thanks to reactive core components, reactivity can be optionally added on top without writing JavaScript, just using a simple Ruby DSL.
Talks & Podcasts
I love to share thoughts and ideas with an audience
When I started out in software engineering, I never imagined myself to be on a big stage. But then my former cofounder and good friend Pascal pushed me to talk on the Ruby Unconf 2019, and I have to admit: I was super nervous, but in the end I really enjoyed the experience! Looking forward to participating in quite some more events once we've beaten Covid!
Highlighted talks and podcasts
Remote Ruby 11/2020
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Andrew, Chris and Jason from the Remote Ruby podcast invited me to talk about my open source project, matestack-ui-core. I was super happy about the invitation and grateful for the opportunity to chat with these guys about open source, business models and technology - thanks again!
RUG::B 10/2020
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In this Rug::B meetup, I demonstrated how to build a reactive Dropbox-like web UI in pure Ruby. Some cute puppies may have helped me to enrich the talk ;)
RubyC 09/2020
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I was super excited when I received an invitation to be a speaker on the RubyC conference. Due to Covid, the conference unfortunately had to be canceled. A series of meetups were held as a substitute. On this one, I've talked about my open source project and discussed various questions with the audience. Looking forward to participate on the real conference next time!
Ruby Unconf Hamburg 06/2019
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Shortly after the first public release of matestack-ui-core, I proposed a talk on the 2019 Ruby Unconf in Hamburg. In front of an audience of around 150 people, I demonstrated my ideas of rapid UI development on a pretty big stage. It was a blast - for me and the audience, who voted the talk into the top 5 of the whole conference!