Latest tech post



  • Kotlin null safety and its performance considerations -- part 1

    Kotlin may seem like a new kid on the block – itʼs been officially released only in February. Its history however dates a few years back and itʼs mature and stable enough to be used for developing solid reliable applications. Therefore at Allegro we decided to give it a chance – we built our new shiny server-side system using Kotlin as its primary language and we do not regret it.

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  • Meet Retrofit2

    In this post I will introduce to you a recently released version of a well known library for consuming RESTful services — Retrofit2. Even though it is mainly targeted at Android platform it works very well on the “server” Java. Its lightness and low garbage generation overhead make it an interesting option if one does not like existing solutions (like Jersey Client, or Spring’s RestTemplate). I will also show how to configure it properly and fully utilize its great RxJava compatibility.

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  • Writing a very fast cache service with millions of entries in Go

    Recently our team has been tasked to write a very fast cache service. The goal was pretty clear but possible to achieve in many ways. Finally we decided to try something new and implement the service in Go. We have described how we did it and what values come from that.

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  • Managing Frontend in the Microservices Architecture

    Microservices are now the mainstream approach for scalable systems architecture. There is little controversy when we are talking about designing backend services. Well-behaved backend microservice should cover one BoundedContext and communicate over the REST API. Things get complicated when we need to use microservices as building blocks for a frontend solution. How to build a consistent website or a mobile app using tens or sometimes hundreds of microservices?

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  • Integrating Android project with Codecov

    If you always search for ways to increase code quality and would like to encourage everyone in your project to keep high test code coverage all the time, then Codecov may be another step in your journey.

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  • Books you should read: The Pragmatic Programmer

    Some books on IT topics become outdated right after they are published while others stand the test of time. One of the latter is The Pragmatic Programmer. From Journeyman to Master by Andrew Hunt and David Thomas.

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  • The great adventure of migrating Allegro infrastructure to new Data Center - DC5

    Moving Allegro’s services and infrastructure from its main Data Center (DC) was considered a huge endeavour fraught with high risk from the very start. This particular Data Center, known as DC2, was situated in Poznań, Poland. It was our first genuine Data Center and back in 2007, when we moved in there, it was the state—of—the—art DC in Poland. For a couple of years our infrastructure was growing along with the company and the number of devices grew up to 2,000 filling 90 rack cabinets in 2014. DC was used by Allegro core sites such as allegro.pl, aukro.ua and aukro.cz as well as other Naspers-owned Polish operations like: payu.pl, olx.pl, ceneo.pl, otomoto.pl, otodom.pl. To make the story simpler, Allegro synonym is used to name them all.

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allegro.tech

At Allegro, we build and maintain some of the most distributed and scalable applications in Central Europe. This poses many challenges, starting with architecture and design, through the choice of technologies, code quality and performance tuning, and ending with deployment and devops. In this blog, our engineers share their experiences and write about some of the interesting things taking place at the company.