Consultant / Software Developer
(500-1000 Mitarbeiter)
Schlagwörter
Javascript
Web Entwicklung
Python
Ruby
C++
Software Quality
Soziale Kompetenz
Softwareentwicklung
SQL
Teamarbeit
Skills
I have over 20 years experience of professional software development and various roles within it. For more than a decade, I have focused on developing web applications, mostly working on the back-ends but I have experience of implementing front-ends as well.
In recent years, my most used programming languages and frameworks have been Ruby and Ruby on Rails, Python and Django, JavaScript both in the back-end and front-end, also with React.js and Vue.js. I have used Go (Golang) and TypeScript, too, and did C++ and C for several years, previously.
I have used SQL databases for over 20 years, recently mostly PostgreSQL and MySQL but also MS SQL Server and Oracle in the past, and some experience of NoSQL, mostly Redis and MongoDB.
In the cloud, I have over a decade of experience of using AWS and Heroku.
Please see my CV for longer lists of my skills.
I mostly help my clients by implementing software but I have also helped them become more agile, elevate their team skills, move software into the cloud, plan projects, recruit new developers, and adopt good and transparent communication practices, to name a few of my other contributions.
I value:
Code and software quality.
Learning.
Helping others learn and succeed.
Teamwork.
Transparency and openness.
In recent years, my most used programming languages and frameworks have been Ruby and Ruby on Rails, Python and Django, JavaScript both in the back-end and front-end, also with React.js and Vue.js. I have used Go (Golang) and TypeScript, too, and did C++ and C for several years, previously.
I have used SQL databases for over 20 years, recently mostly PostgreSQL and MySQL but also MS SQL Server and Oracle in the past, and some experience of NoSQL, mostly Redis and MongoDB.
In the cloud, I have over a decade of experience of using AWS and Heroku.
Please see my CV for longer lists of my skills.
I mostly help my clients by implementing software but I have also helped them become more agile, elevate their team skills, move software into the cloud, plan projects, recruit new developers, and adopt good and transparent communication practices, to name a few of my other contributions.
I value:
Code and software quality.
Learning.
Helping others learn and succeed.
Teamwork.
Transparency and openness.
Projekthistorie
09/2022
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01/2023
Language learning platform
I joined a client’s payment team to help them implement the transition from an old software architecture into a new one. Among other things, I made a proof-of-concept on how to get sales reports from Apple for purchases made through an iOS app, and integrated Shopify to their existing system, both of which would help increase the accuracy of their accounting and reporting. Integrating with Shopify decreased their customer feedback work by about 80 %.
Technologies: Ruby on Rails, RSpec, MySQL, AWS, integrations, microservices, event-driven, background processing, iOS in-app purchases, Scrum, Docker, Shopify webhooks
I joined a client’s payment team to help them implement the transition from an old software architecture into a new one. Among other things, I made a proof-of-concept on how to get sales reports from Apple for purchases made through an iOS app, and integrated Shopify to their existing system, both of which would help increase the accuracy of their accounting and reporting. Integrating with Shopify decreased their customer feedback work by about 80 %.
Technologies: Ruby on Rails, RSpec, MySQL, AWS, integrations, microservices, event-driven, background processing, iOS in-app purchases, Scrum, Docker, Shopify webhooks
11/2021
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08/2022
Consultant / Software Developer / Interim CTO / Tech Lead
Platform for finding venues for private and corporate events
I substituted the CTO and tech lead. I was to focus on developing the back-end, maintaining the infrastructure, and facilitating parts of their process. In practice, I also worked on the front-end, helped plan their upcoming recruitment, introduced Typescript as a proof-of-concept, implemented integrations to Pipedrive CRM, and coached and mentored another developer.
Technologies: Ruby on Rails, RSpec, MySQL, Redis, React.js, JavaScript, Flow, Cypress, Jest, Storybook, Chromatic, Typescript, ElasticSearch, Docker, background processing, integrations, Mandrill (Mailchimp), Pipedrive API, AWS, Heroku, Depfu, pair programming, Scrumban
I substituted the CTO and tech lead. I was to focus on developing the back-end, maintaining the infrastructure, and facilitating parts of their process. In practice, I also worked on the front-end, helped plan their upcoming recruitment, introduced Typescript as a proof-of-concept, implemented integrations to Pipedrive CRM, and coached and mentored another developer.
Technologies: Ruby on Rails, RSpec, MySQL, Redis, React.js, JavaScript, Flow, Cypress, Jest, Storybook, Chromatic, Typescript, ElasticSearch, Docker, background processing, integrations, Mandrill (Mailchimp), Pipedrive API, AWS, Heroku, Depfu, pair programming, Scrumban
11/2021
-
07/2022
Software Developer
(50-250 Mitarbeiter)
International consulting company
I contributed to this website both as a developer implementing features and fixing bugs, but also as a coach helping to define and improve the process we used to develop it with irregular resources.
Technologies: Gatsby, Contentful, React.js, JavaScript, GraphQL, Cypress
06/2021
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08/2021
Consultant
Education platform
My task was to identify the causes of degrading performance and increased memory consumption of an old application running in Heroku, and to present suggestions on how to improve the situation.
Technologies: Ruby on Rails, PostgreSQL, JavaScript, React.js
My task was to identify the causes of degrading performance and increased memory consumption of an old application running in Heroku, and to present suggestions on how to improve the situation.
Technologies: Ruby on Rails, PostgreSQL, JavaScript, React.js
02/2021
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05/2021
Consultant / Software Developer / Interim CTO / Tech Lead
Company providing career trend reports
A client wanted to allow their customers access to more and new reports with Tableau data through their existing application, so that they only had access to the studies they had subscribed to and to the dashboards that they had permissions to.
I had a lot of issues connecting to Tableau, and I had to debug them for a remote server that I did not have access to, because of a third party Tableau provider.
I implemented subscriptions and permissions management, and a simple API for another team. I was joined by a colleague to help me with some front-end work for 2-3 weeks towards the end of the project due to the designs coming so late and because solving the Tableau problems took so much of my time. I helped my colleague learn Ruby on Rails before he joined the project, so that he was also able to write some simpler back-end code.
I had monthly calls with the new CTO before he started so that he was better prepared for what to expect.
Technologies: Ruby on Rails, RSpec, PostgreSQL, JavaScript, Tableau, Heroku
A client wanted to allow their customers access to more and new reports with Tableau data through their existing application, so that they only had access to the studies they had subscribed to and to the dashboards that they had permissions to.
I had a lot of issues connecting to Tableau, and I had to debug them for a remote server that I did not have access to, because of a third party Tableau provider.
I implemented subscriptions and permissions management, and a simple API for another team. I was joined by a colleague to help me with some front-end work for 2-3 weeks towards the end of the project due to the designs coming so late and because solving the Tableau problems took so much of my time. I helped my colleague learn Ruby on Rails before he joined the project, so that he was also able to write some simpler back-end code.
I had monthly calls with the new CTO before he started so that he was better prepared for what to expect.
Technologies: Ruby on Rails, RSpec, PostgreSQL, JavaScript, Tableau, Heroku
01/2021
-
02/2021
Consultant / Software Developer
Company providing career trend reports
A client wanted to allow their customers access to some reports and Tableau data through their existing application based on permissions.
I implemented the embedding of Tableau data and handling of the permissions so that customers had access to only the editions they had subscribed to.
Technologies: Ruby on Rails, RSpec, PostgreSQL, JavaScript, Tableau, Heroku
A client wanted to allow their customers access to some reports and Tableau data through their existing application based on permissions.
I implemented the embedding of Tableau data and handling of the permissions so that customers had access to only the editions they had subscribed to.
Technologies: Ruby on Rails, RSpec, PostgreSQL, JavaScript, Tableau, Heroku
11/2020
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01/2021
Consultant / Software Developer / Project Manager
Company providing career trend reports
A client had an application that integrated with Tableau but they were missing how to navigate the Tableau data. We needed to fix bugs before getting to implement the Tableau navigation.
I was mostly involved in specifying the work expected of us with their CIO and supervising the work of our freelancer, but also did code reviews and pair programming.
Technologies: Ruby on Rails, RSpec, PostgreSQL, JavaScript, Tableau, Heroku
A client had an application that integrated with Tableau but they were missing how to navigate the Tableau data. We needed to fix bugs before getting to implement the Tableau navigation.
I was mostly involved in specifying the work expected of us with their CIO and supervising the work of our freelancer, but also did code reviews and pair programming.
Technologies: Ruby on Rails, RSpec, PostgreSQL, JavaScript, Tableau, Heroku
07/2020
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01/2021
Consultant / Software Developer / Mentor
Search engine web application
My task was to join their Engagement team to elevate their skills and help them perform better.
My responsibilities were to bring in some generic software development experience, improve their software architecture, write back-end and front-end code, help them use Scrum and agile processes, in general, and to coach and mentor our team's interim lead developer, and others, to become better developers. I was also reviewing and commenting on other back-end developers' code to help them improve code quality and code readability.
A colleague of mine was in the same team as a front-end developer, and together we managed to establish some improvements on how to better leverage GitHub and pull requests.
Technologies: Go, gRPC, Gorilla, Python, JavaScript, Backbone.js, PostgreSQL, Jsonnet, Docker, Kubernetes, pair programming, code reviews, Scrum
My task was to join their Engagement team to elevate their skills and help them perform better.
My responsibilities were to bring in some generic software development experience, improve their software architecture, write back-end and front-end code, help them use Scrum and agile processes, in general, and to coach and mentor our team's interim lead developer, and others, to become better developers. I was also reviewing and commenting on other back-end developers' code to help them improve code quality and code readability.
A colleague of mine was in the same team as a front-end developer, and together we managed to establish some improvements on how to better leverage GitHub and pull requests.
Technologies: Go, gRPC, Gorilla, Python, JavaScript, Backbone.js, PostgreSQL, Jsonnet, Docker, Kubernetes, pair programming, code reviews, Scrum
05/2019
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06/2020
Consultant / Software Developer
Car-sharing company
I joined their payment team that was responsible for handling the payment back-end that provided an API for the other parts in the system and heavily used background processing.
My responsibilities included helping out the team in their development work. I rewrote an old component as a proof of concept, replaced the use of test fixtures with test factories, and gave more comments in code reviews to maintain high code quality. I also implemented features to allow users to pay their outstanding invoices on their own, to block and unblock a user based on their payments, to create credit card pre-authorizations before rentals and to collect data about them for later use in order to save potentially over 1 mEUR per year.
I substituted our team's QA for three weeks during their holidays. This was mostly about writing end-to-end tests but I also improved the overall level of test code by showing how to use the tools better, showing good practices for code and logging, and refactoring some of the test code.
Technologies: Ruby on Rails, Minitest, Cucumber, PostgreSQL, MongoDB, integrations, background processing, microservices, event-driven, Kaa, RabbitMQ, Docker, Kubernetes, JavaScript, Vue.js, Stripe, pair programming, code reviews, Scrum
I joined their payment team that was responsible for handling the payment back-end that provided an API for the other parts in the system and heavily used background processing.
My responsibilities included helping out the team in their development work. I rewrote an old component as a proof of concept, replaced the use of test fixtures with test factories, and gave more comments in code reviews to maintain high code quality. I also implemented features to allow users to pay their outstanding invoices on their own, to block and unblock a user based on their payments, to create credit card pre-authorizations before rentals and to collect data about them for later use in order to save potentially over 1 mEUR per year.
I substituted our team's QA for three weeks during their holidays. This was mostly about writing end-to-end tests but I also improved the overall level of test code by showing how to use the tools better, showing good practices for code and logging, and refactoring some of the test code.
Technologies: Ruby on Rails, Minitest, Cucumber, PostgreSQL, MongoDB, integrations, background processing, microservices, event-driven, Kaa, RabbitMQ, Docker, Kubernetes, JavaScript, Vue.js, Stripe, pair programming, code reviews, Scrum
01/2019
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01/2019
Consultant / Software Developer
Platform for post-flight passenger feedback, phase 2
The client wanted me to update some libraries that had security vulnerability notifications on GitHub. I updated the Docker definitions so that there was a working setup to use Docker locally. We agreed that I write some tests because in the first development phase none were written. I wrote RSpec tests for the back-end API, and Cypress tests for end-to-end testing.
Technologies: Ruby on Rails, RSpec, PostgreSQL, React.js, JavaScript, Cypress, Docker, AWS
The client wanted me to update some libraries that had security vulnerability notifications on GitHub. I updated the Docker definitions so that there was a working setup to use Docker locally. We agreed that I write some tests because in the first development phase none were written. I wrote RSpec tests for the back-end API, and Cypress tests for end-to-end testing.
Technologies: Ruby on Rails, RSpec, PostgreSQL, React.js, JavaScript, Cypress, Docker, AWS
08/2018
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10/2018
Consultant / Software Developer
Platform for post-flight passenger feedback
The goal of this project was to develop an app to collect post-flight user feedback about airlines and airports. The target audience was the registered users of our client’s app and website.
My tasks involved setting up the infrastructure in AWS, developing the front-end according to the wireframes the client had, developing the back-end, and deploying it all to production. It was like an MVP or a proof-of-concept without authentication or any security features nor tests (client's decision).
Our customer integrated this app to their React Native app, and synchronized some of the data from their other app’s database to this one on a daily basis so that we had up-to-date users and flights data.
Technologies: Ruby on Rails, PostgreSQL, React.js, JavaScript, Docker, AWS
The goal of this project was to develop an app to collect post-flight user feedback about airlines and airports. The target audience was the registered users of our client’s app and website.
My tasks involved setting up the infrastructure in AWS, developing the front-end according to the wireframes the client had, developing the back-end, and deploying it all to production. It was like an MVP or a proof-of-concept without authentication or any security features nor tests (client's decision).
Our customer integrated this app to their React Native app, and synchronized some of the data from their other app’s database to this one on a daily basis so that we had up-to-date users and flights data.
Technologies: Ruby on Rails, PostgreSQL, React.js, JavaScript, Docker, AWS
06/2018
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07/2018
Consultant / Software Developer
Company offering services for non-profits
I joined the team to help develop further a platform used to help non-profit organizations find temporary help for various tasks.
Technologies: Ruby on Rails, MySQL, e-mail integration
I joined the team to help develop further a platform used to help non-profit organizations find temporary help for various tasks.
Technologies: Ruby on Rails, MySQL, e-mail integration
05/2018
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06/2018
Consultant
Career and job seeker platform
My task was to assess the quality of the code of a career and job seeker platform used in Africa as our client wanted to integrate it in their existing systems.
Technologies: Ruby on Rails, PostgreSQL
My task was to assess the quality of the code of a career and job seeker platform used in Africa as our client wanted to integrate it in their existing systems.
Technologies: Ruby on Rails, PostgreSQL
02/2018
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04/2018
Consultant / Software Developer
Fintech wealth management company
I was tasked with improving the performance of their admin panel pages by optimizing their database queries and code so that their operations people could do their job without the pages timing out or crashing.
Technologies: Ruby on Rails, PostgreSQL, ActiveAdmin
I was tasked with improving the performance of their admin panel pages by optimizing their database queries and code so that their operations people could do their job without the pages timing out or crashing.
Technologies: Ruby on Rails, PostgreSQL, ActiveAdmin
10/2017
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03/2018
Consultant / Software Developer
Large shipyard
My main responsibility was to add an admin panel section to an already implemented shipyard worker overtime reporting system. Additionally, I fixed some bugs in the previous code.
The project turned out to be quite challenging as I had to learn both the back-end and front-end technologies while making the changes.
Technologies: Scala, Play, Elm, PostgreSQL, Heroku
My main responsibility was to add an admin panel section to an already implemented shipyard worker overtime reporting system. Additionally, I fixed some bugs in the previous code.
The project turned out to be quite challenging as I had to learn both the back-end and front-end technologies while making the changes.
Technologies: Scala, Play, Elm, PostgreSQL, Heroku
04/2017
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10/2017
Consultant / Software Developer
Facebook ads platform product
I helped our client develop their back-end services for their product on the Facebook Ads platform. I also made some minor changes to the front-end.
Technologies: Ruby on Rails, PostgreSQL, PHP, MongoDB, Cassandra, Angular, Scrum
I helped our client develop their back-end services for their product on the Facebook Ads platform. I also made some minor changes to the front-end.
Technologies: Ruby on Rails, PostgreSQL, PHP, MongoDB, Cassandra, Angular, Scrum
01/2016
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04/2017
Consultant / Software Developer
Platform for short-term accommodation
A client bought an AirBnB-type app codebase that I helped maintain and develop further.
Together with a colleague, we first specified what we needed as a handover from the seller’s team to help us take ownership of the codebase and app.
To run the app for our client, I set up a similar infrastructure as what the existing team had used in DigitalOcean and AWS.
Among many of the smaller changes and fixes, I re-wrote parts of the integration that was used to fetch and import properties from an external service.
Technologies: Ruby on Rails, RSpec, JavaScript, MySQL, Redis, background processing, Kigo API, Adyen, PayPal, payment integration
A client bought an AirBnB-type app codebase that I helped maintain and develop further.
Together with a colleague, we first specified what we needed as a handover from the seller’s team to help us take ownership of the codebase and app.
To run the app for our client, I set up a similar infrastructure as what the existing team had used in DigitalOcean and AWS.
Among many of the smaller changes and fixes, I re-wrote parts of the integration that was used to fetch and import properties from an external service.
Technologies: Ruby on Rails, RSpec, JavaScript, MySQL, Redis, background processing, Kigo API, Adyen, PayPal, payment integration
07/2015
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01/2016
Consultant / Software Developer
Marketplace for artists and venues
I helped develop the initial marketplace for venue owners to book artists.
Technologies: Ruby on Rails, JavaScript, PostgreSQL, Cucumber, background processing, Heroku, Stripe, payment integration
I helped develop the initial marketplace for venue owners to book artists.
Technologies: Ruby on Rails, JavaScript, PostgreSQL, Cucumber, background processing, Heroku, Stripe, payment integration
10/2015
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10/2015
Consultant
Platform for short-term accommodation
My task was to help a client decide whether or not to buy an AirBnB-type web app and its source code by performing a quick technical audit for it.
I interviewed the old team, took a look at their documentation and the code, and presented my findings and recommendations to our client.
Technologies: Ruby on Rails, JavaScript, MySQL, Kigo
My task was to help a client decide whether or not to buy an AirBnB-type web app and its source code by performing a quick technical audit for it.
I interviewed the old team, took a look at their documentation and the code, and presented my findings and recommendations to our client.
Technologies: Ruby on Rails, JavaScript, MySQL, Kigo
01/2015
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07/2015
Consultant / Software Developer
Private employment agency
Development of a web application to keep track of daily sales tally of services and devices for mobile operator sales personnel. A client had previously built an MVP with PHP and Google Sheets for tracking sales activities that didn't scale anymore.
Technologies: Node.js, Express.js, JavaScript, MySQL, Jade (Pug), AWS
Development of a web application to keep track of daily sales tally of services and devices for mobile operator sales personnel. A client had previously built an MVP with PHP and Google Sheets for tracking sales activities that didn't scale anymore.
Technologies: Node.js, Express.js, JavaScript, MySQL, Jade (Pug), AWS
12/2014
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01/2015
Consultant / Software Developer
Implemented an integration module for a university to connect a new application with
an old database.
Technologies: Ruby, Oracle
an old database.
Technologies: Ruby, Oracle
08/2011
-
01/2015
Software Architect and Consultant
Joined a small software consultancy.
Projects:
Implemented an integration module for a university to connect a new application with
an old database.
Experimented with a couple of iOS proof-of-concept apps about navigation.
Developed an image processing service for real estate agents.
Developed a real-time publishing application for an energy market.
Helped develop a router management interface for an information security company.
Projects:
Implemented an integration module for a university to connect a new application with
an old database.
- Role: Consultant / Software Developer
- Technologies: Ruby, Oracle
Experimented with a couple of iOS proof-of-concept apps about navigation.
- Role: Software Developer
- Technologies: iOS, Objective-C
Developed an image processing service for real estate agents.
- Role: Consultant / Software Developer
- Technologies: Python, Django, CoffeeScript, MySQL, AWS
Developed a real-time publishing application for an energy market.
- Roles: Consultant / Software Developer / Scrum Master / Project Manager
- Technologies: Python, Django, CoffeeScript, Batman.js, PostgreSQL, AWS, Selenium, pair programming, Scrum, project management
Helped develop a router management interface for an information security company.
- Role: Consultant / Software Developer
- Technologies: Linux, Java, Wicket, JavaScript, Python, PostgreSQL, Node.js
02/2011
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07/2011
Technical Project Manager and Senior Software Developer
Joined a software consultancy.
Projects:
Prepared a public tender for public transport ticket management web application.
Worked on an internal web project for project and allocation management.
Projects:
Prepared a public tender for public transport ticket management web application.
- Role: Project Manager
Worked on an internal web project for project and allocation management.
- Role: Lead Software Developer / Scrum Master
- Technologies: Ruby on Rails, RSpec, JavaScript, Backbone.js, PostgreSQL, Linux, pair programming
08/2005
-
01/2011
Software Engineer / Team Manager / Technical Product Manager / Senior Software Engineer
Worked in many roles, such as Software Engineer, Team Manager, Configuration Management Engineer, Technical Product Manager, Scrum Master, Product Owner, and Agile coach.
As a team manager, in addition to my software development responsibilities, took care of anything related to my team members' work and career-related topics for first a 5-person team, and later for a 10-person team. I also substituted our Site Manager on their summer holiday.
Projects:
Developed the first version of an innovative workforce management product.
Helped start up a new web project
Helped develop further a couple of mobile products.
Helped develop further an innovative mobile browser.
Helped develop various mobile platforms applications for a big mobile phone company over several years.
As a team manager, in addition to my software development responsibilities, took care of anything related to my team members' work and career-related topics for first a 5-person team, and later for a 10-person team. I also substituted our Site Manager on their summer holiday.
Projects:
Developed the first version of an innovative workforce management product.
- Role: Software Developer / Scrum Master / Product Owner / Project Manager
- Technologies: Ruby on Rails, JavaScript, MySQL, background processing, SMS, integrations, pair programming, code reviews, Scrum, project management, product management
Helped start up a new web project
- Role: Scrum Master / Agile coach
- Technologies: Ruby on Rails, MySQL, SMS
Helped develop further a couple of mobile products.
- Role: Software Developer
- Technologies: C++, Symbian, S60
Helped develop further an innovative mobile browser.
- Role: Software Developer / Scrum Master
- Technologies: C++, Qt, Maemo, Meego
Helped develop various mobile platforms applications for a big mobile phone company over several years.
- Role: Software Developer / Configuration Management Engineer / Build Manager / Agile coach
- Technologies: C++, Symbian, S60, unit testing, Perl, Python, C, Maemo (Meego), code reviews
06/2005
-
07/2005
Software Developer
Large insurance company in San Francisco, California
Joined an internal service request management project that was eventually canceled.
Joined an internal service request management project that was eventually canceled.
- Technologies: JavaScript, SQL, visualizing and “debugging” processes
08/1999
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10/2004
Software Developer
I joined a small product development company.
I worked mainly on a modern library management system and its web interface.
Technologies: C++, Delphi, Microsoft COM, MS SQL Server, SMS, integrations, Classic ASP, JScript, JavaScript, pair programming, code reviews
I also worked on an internal project and task management system on the side of the main product.
Technologies: Classic ASP, JScript, JavaScript, pair programming
I worked mainly on a modern library management system and its web interface.
Technologies: C++, Delphi, Microsoft COM, MS SQL Server, SMS, integrations, Classic ASP, JScript, JavaScript, pair programming, code reviews
I also worked on an internal project and task management system on the side of the main product.
Technologies: Classic ASP, JScript, JavaScript, pair programming
Zertifikate
Reisebereitschaft
Weltweit verfügbar
Traveling is negotiable.
