About 4xxi

Web & mobile development company 4xxi

4xxi is a world-class web & mobile development company helping Startups, SMB and Enterprises to solve their business problems, accomplish goals, increase revenues and cut costs.

We change industries. And even people's lives.

We have a deep product expertise in FinTech, EdTech and MedTech industry. Also we can create and like products with Big Data, Artifical Intelligence and Machine Learning. There are more than 80 excellent global projects in our portfolio, most of them regularly get publications in Forbes, TechCrunch, New York Times, Yahoo, Business Insider etc.

We are a certified partner of SensioLabs.

Our concise technology stack: Symfony / PHP / PostgreSQL / MySQL / MongoDB / Redis / RabbitMQ / React / Redux / PostCSS / Ruby / Rails etc.

  • Founded : 2008
  • Strength : 51 to 250
  • Phone : 79046414387
  • Cost Per Hour : $26 - $50
  • Minimum Project Amount : Less than $5000


2-G Malaya Monetnaya St., 403, Saint Peterburg, SPE-197101, Russia

Tereshkova street, 7A, Saransk, MO-197101, Russia

4xxi Reviews

Submit a review for 4xxi

Review by David Nadezhdin

Woolmark Prize

Reviewed by David Nadezhdin , Co Founder, CEO at SIG.NUM
date_range 2017-08-09
monetization_on $10001 - $25000
important_devices Web and Software Development
check_circle completed
5.0 Reliability & Trustworthy
5.0 Quality Of Service
5.0 Creativity & Expertise
5.0 Timelines & Budget
Overall Rating

We just provided 4xxi the concept of the project and the designs. We needed: a website (backend and frontend) + server infrastructure setup & support. Due to the limited time we had a lot of calls to finalize the scope.

Services & Focus


Industry Focus

Client Focus


Key clients


Get in touch

email [email protected]

call 79046414387

Get in touch keyboard_arrow_upkeyboard_arrow_down

email [email protected]

call 79046414387