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Web & Mobile development

We work on world-class projects that change industries.
And sometimes people's lives.
That's just the way it is — we make excellent products.
Our technology stack:

Expertise

Our in-depth understanding of finance, education and medicine allows customers from these industries to stand alongside our much-loved existing clients who have already been featured in leading publications around the world. For more than 9 years we have been developing the complex projects and helping our clients to achieve international success.
They write about our projects:

Our projects

Contact us

We are ready to demonstrate why we are so good from the very first day. Contact us any way that suits you best:

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About Us

We regard each project as our own. This is why our clients recommend 4xxi to their friends and business partners. We are simply incapable of not caring about what we do. We use modern development, management and testing standards.

Contacts

  • HQ Office / London
    23 Leyborne Park, Kew Gardens, Richmond, Surrey, UK, TW9 3HB
    HQ Office / London
    23 Leyborne Park, Kew Gardens, Richmond, Surrey, UK, TW9 3HB
  • Office / Serbia
    Belgrade, Kraljice Marije 39
    Office / Serbia
    Belgrade, Kraljice Marije 39
  • Office / Montenegro
    Herceg Novi, Dr. Jova Bijelica 17
    Office / Montenegro
    Herceg Novi, Dr. Jova Bijelica 17
  • Office / United States
    147 E 97th St, New York, NY 10029
    Office / United States
    147 E 97th St, New York, NY 10029