Phone:+420 603 563 516
E-mail:hanz.krnavek@gmail.com

Your technology partner for software development and digital products

Specialist in the Python programming language, the Django web framework and the Django REST framework.

I design and build complex web applications that meet demanding requirements for performance, software security and a good user experience.

Visit me at my Brno office for a free consultation, call me or send an e-mail.
Software engineer, developer and freelancer Ing. Jan Krňávek.

Software solutions in Python and the Django web framework

  • I consult your requirements, design the software architecture, write the project documentation and build the application under the agreed terms.
  • I build websites and complex web applications in the Python programming language and the Django framework.
  • I integrate your Python or Django application with your information system or a third-party backend.
  • I design and implement REST API backends built on the Django REST Framework, suitable for example for the Android and iOS mobile platforms.
  • I implement and configure the Django CMS content management system for your website, including SEO, training, operation and support.
  • I carry out security and technology audits of Django applications, including a report on the current state and recommendations for improvement.
  • I upgrade the code of your Django application to the current versions of Python 3 and Django (including the LTS releases) and update its packages.
  • Based on your requirements I extend your Python and Django application with new features or improve its user interface.
  • I analyse performance problems of Python and Django applications and propose solutions.
  • I modify, complete or fix Django applications built by a third party.
  • I develop Python and Django applications as a subcontractor according to a digital agency's specification.

Design, development and programming of software in Python, the Django web framework and the Django REST Framework.

Design, development, growth and maintenance of Python and Django applications

    I write custom software. I turn your idea or business needs into a working, maintainable Python and Django application. Once it is finished I do not leave you on your own: I take care of further development, bug fixing, maintenance and user support.

    First we identify the key requirements together, analyse the users' needs and define the software architecture. The findings go into the project documentation.

    The specification describes the features the customer expects, clearly defines the final product and is essential for the quotation and the schedule.

    Do you need a Python and Django application designed or built? Contact me for a free consultation or simply drop by my office in Brno.

Solving operational and performance problems of Python and Django applications

    During the life cycle of a Python and Django application, various kinds of problems can appear that require expert intervention.

    For example code changes, new data integrations and interfaces, updates of software components and packages, reconfiguration of the runtime environment, a new backup strategy, or new security keys, passwords and user roles.

    Performance problems are a chapter of their own. Their causes range from a poorly designed application architecture or an unsuitable user interface to unexpected data growth, undersized hardware or a badly designed network infrastructure.

    Are you facing one of these problems and do not know where to start? Get in touch, I will be glad to help.

Software audit of Python and Django applications

    I audit the source code of your Python and Django application built by a third party. In plain language I map and describe its current state, including suggestions for improving functionality, the user interface and security.

    The service includes a report assessing the quality of the code and documentation and describing the software architecture and runtime infrastructure, plus a list of the Python and Django components, modules and libraries used. A separate section analyses the risks worth your attention.

    The audit report gives you a basic overview of the technological and security state of your application. You can use it to discuss further development or as a supporting, independent document when negotiating with your current software supplier.

Design and implementation of websites with Django CMS

    Django CMS is an advanced web content management system built on the Django framework. It is the counterpart of WordPress in the Python world and suits complex web presences as well as simple websites.

    Key features include a user-friendly interface, responsive design, multilingual publishing, a permission system for managers and editors, extensibility through existing plugins and built-in SEO support.

    I design, build and launch a website on Django CMS that works well on desktops, tablets and mobile devices, and I take care of its operation, development, maintenance, user support and basic SEO.

How much does it cost?

    I prefer a fixed price per task or project. It keeps the collaboration simpler and clearly defined for both the customer and me. Any additional work is priced individually.

    For projects, the first step is a paid analysis of the customer's requirements. The requirements and the way the application works are specified in the project documentation.

    The project documentation contains the agreed assignment, the technical specification, the final price and a rough schedule. It is the necessary basis for a binding order or a contract for work. New customers are asked for an advance payment.

    I also offer collaboration at an hourly rate corresponding to the usual market level. A discounted hourly rate can be agreed for long-term cooperation.

The principles I follow

  • What I promise, I deliver.
  • I do not create technical debt.
  • I meet the agreed deadlines.
  • I do not repeat the same mistake twice.
  • I listen to my customers and like to stay in regular contact with them.
  • I recommend the solution that best fits the customer's current situation and needs.
  • What matters is the result, not the number of hours worked.
  • Good work deserves a fair reward.
  • I will take care of your application in the future as well.
  • What I cannot do yet, I will learn.
  • I do not lead my customers up the garden path.

The IT technologies I work with

    I have experience administering Linux and Windows servers and branded DELL and HP hardware, and hands-on experience with Red Hat, CentOS, AlmaLinux, Debian and Ubuntu. I manage PostgreSQL, MySQL, Redis and MongoDB databases and install and configure Apache, Nginx, PHP, mod_wsgi, uWSGI, Gunicorn, HTTPS and other services. I also have experience running Linux KVM, VMware and Docker virtualisation and the AWS cloud platform.

    The advantage for the customer: if needed, I can deploy a Python or Django project to production without an external administrator. I also debug errors and performance problems faster, because I understand what is going on under the hood.

  • Python 3
  • Django Web Framework
  • Django CMS – content management system
  • Django REST Framework (REST API)
  • HTML5, CSS, SASS, Bootstrap, Material Design, Vuetify
  • JavaScript, jQuery
  • The Vue.js JavaScript framework including Vue Router and Pinia
  • Source code is kept in Git
  • Experience operating and configuring Atlassian Jira and Confluence

Why are Python and Django a good choice for building web applications?

    Django is a mature open-source framework for building websites and web applications. It is built on the Python programming language, whose code is short and easy to read compared with other languages.

    From the very beginning Django was designed to help developers build applications efficiently and quickly. At every step – from the idea through implementation and testing to production deployment – its well-thought-out architecture naturally lowers development and maintenance costs.

    Django has many useful features that simplify development. Its rich ecosystem of thousands of packages, for example, makes it easy to find and integrate new functionality into an existing project with minimal effort. That is why it is popular with freelance developers as well as established web companies, which prefer Python and Django for their high productivity and low development costs.

Where are Python and Django used?

  • Customer relationship management (CRM) systems.
  • Content management systems (CMS) for internal and public websites.
  • Communication platforms.
  • Booking systems.
  • Data analytics systems.
  • Scientific systems for parallel computing.
  • E-mail solutions.
  • Document management systems.
  • Financial platforms (FinTech).
  • AI systems using machine learning or neural networks.
  • Backend systems for the Android and iOS mobile platforms.
  • Systems supporting real-estate transactions and mortgage credit scoring.
  • Security systems based on image or sound recognition.

    Django and Python are used by major companies and organisations worldwide, such as Instagram, NASA, Pinterest, Reddit, YouTube, Dropbox and others.

    In one sentence: Django combined with Python is simply great – it is pleasant and fast to program in, and it gently enforces good engineering practice that leads to readable, maintainable code. Django and Python simply pay off.

I look forward to working with you

    I have worked in information technology since 2005. I deliver demanding web and intranet applications built with Python and the Django framework – custom software from design and development to final deployment at the customer, including training.

    I hold university degrees in engineering and economics, so I can look at your problem from both the business and the technical IT perspective. I like to apply the principles of minimalism in my work. I speak Czech and English.