Data classes in Kotlin: how do they impact an application size

Kotlin has numerous excellent features: null safety, smart casts, string interpolation and more. However, one of its features developers love the most, I have observed, are data classes. They are so well-loved that they are often used where no data class functionality is required. In this article, with the help…

Achieving State Of The Art Results In Natural Language Processing

Part 2: ELMo, BERT and MT-DNN In my previous article I covered some of the fundamental concepts in NLP. This time, I will introduce ELMo, BERT and MT-DNN, architectures which leverage these concepts and have recently achieved some State Of The Art (SOTA) results on NLP tasks. Embeddings from Language Models (ELMo) An introduction to ELMo can be found in this…

Mutation Testing in PHP: quality measurement for code coverage

How do you evaluate how good your tests are? Many people rely on the most popular score, the one everyone knows — code coverage. But this is a quantitative, rather than a qualitative metric. It shows how much of your code is covered by the tests, but not how well…

Features, but faster: the life of an Android developer at Badoo

Practically speaking, my colleagues and I often need to test an idea as fast and as simply as possible. There’s no point spending lots of effort on implementation because we know that if an experiment proves unsuccessful, we are going to jettison the code in question. Here I will be…

Using Hopper to investigate an IOS bug

In this article, I share how we investigated a bug in UIKit, which Apple wasn’t able to solve since the introduction of a new major iOS version until the recent release of iOS 13.4.1. The problem was first noticed in August 2019 with the first beta versions of iOS13. In…

Achieving State Of The Art Results In Natural Language Processing:

Part 1: Fundamental Concepts Badoo is the largest dating network in the world, with over millions of registered users worldwide. Users of our site are prompted to write an “About me” section in order to give any prospective love interests a little bit more information about themselves.

Application localisation:

Hello! I’m Alexey Timin, a Senior Software Engineer at Bumble, in charge of localisation system development. Let me tell you more about our localisation system. We work on two products: Badoo and Bumble and operate more than 150,000 phrases and texts, translated into more than 50 languages. Each project has…

How to move large-scale React UI-components codebase to TypeScript

Hi, my name is Ivan Grekov and I am a frontend developer at Bumble — the parent company operating Badoo and Bumble apps Our frontend team’s main responsibilities are to deliver new user interfaces and support existing ones across our different applications, mostly within Badoo and Bumble websites. At a…

Part 1: Dynamic Delivery in multi-module projects at Bumble

Dynamic Delivery is a technology which allows you to install and delete parts of an application while the application is working, in order to reduce the space it occupied. If there are functions not being used, what is the point of a user having them on their device? In part…

#1 — Swift and iOS Ninjas Meetup: videos, slides and questions!

London isn’t just the capital of England — it’s also the capital of many other things. Including avoiding eye contact with people on the tube or trying to give you a free magazine. And it’s the capital of paying £12 for a cocktail because the barman has a beard. But…

How we achieved a 6x reduction of ANRs. Part 2: Fixing ANRs

In the first part, we discussed what ANR is and what are the ways of tracking it. In this article, you will find information on what problems we found in our application, how we fixed them, and the results we achieved. Application Startup The first thing to do if you want to…

Working with a cache: problems and solutions

Hello all! My name is Victor Pryazhnikov and I’m part of the server team at Badoo. Our team is developing and supporting internal API for our customers server-side, caching data is something we deal with every day. Here’s an interesting opinion when it comes to programming: “There are only two…

Mistakes Unity novices make, based on first-hand experience

Hi, all. It’s me again, Ilya Kudinov, QA engineer at Badoo. Today I am not going to talk about testing but about gamedev. No, this isn’t something we do at Badoo; developing computer games is a hobby of mine. Industry professionals, don’t be harsh in your judgement. All the advice…

Reaktive — a multiplatform library for reactive Kotlin

Reactive programming is really popular today not least because it has loads of plus points: the absence of what is called ‘callback hell’; a built-in mechanism for processing errors; and a functional programming style that reduces the likelihood of bugs occurring. It makes it much easier to write multi-threaded code…

Overview of KotlinConf 2019

I’ve been developing with Kotlin for the past two years, and when I was asked if I’d like to attend KotlinConf 2019 with some of my colleagues, my answer was a great, big Y-E-S! Having the chance to attend what is one of the best conferences for mobile devs, I…

Burnt-out workers: is there a way out?

You work at a good company. You are surrounded by great professionals, you earn a decent salary and every day you carry out important and needful tasks. Elon Musk is launching satellites, Boston Dynamics’ robots are getting better and better. The weather is great, the sun is shining, nature is…

Xcode 10.2, macOS Mojave 10.14.4, iOS 12.1 and other betas

New betas are here and these are some of the most important things that I have learned about them. Swift 5 for Xcode 10.2 beta Swift Firstly, the latest Xcode beta is bundled with the following Swift version: Apple Swift version 5.0 (swiftlang-1001.0.45.7 clang-1001.0.37.7) Target: x86_64-apple-darwin18.2.0 ABI version: 0.6 Let’s start with the most exciting news: Swift…

Optical alignment for frontend developers:

How to align elements in user interfaces. Hi, my name is Ivan Grekov and I work in the front-end team at Badoo. My primary responsibilities entail looking after the user interfaces for a variety of projects. More specifically, this involves working with optical alignment of user interfaces. In this article, I’d like to share with you why…

Swift 4.1 introduction of compactMap

In functional programming, we have a clear definition for what a flatMap function is supposed to be. The flatMap method takes a list and a transformative function (which expects zero or more values for each transformation), applies the transformative function to each member of the provided list, and produces a…

Part 1: Deep Learning for Engineers

Introduction Deep learning has become one of the most discussed topics in the Data Science community. It has long made sense for the Bumble team — the parent company operating Badoo and Bumble apps — to use deep learning on a multitude of tasks. With over millions of users around the…

Server-provided animations in iOS apps

Hi everyone! About six months ago we launched one of Badoo’s most exciting features: Live Streaming. One of its main functionalities is that viewers can send gifts to their favourite streamers to express their appreciation. We wanted to make the gifts as fancy and as engaging as possible, so it…

How we tested iOS 12 Beta

I want to share why it’s important to test betas, how we do it in Badoo and what interesting cases we found during our testing of iOS 12 Beta. Why do we test betas?

Singleton, Service Locator and tests in iOS

In this article, I want to review the usage of Singleton and Service Locator patterns in iOS and the reasons why they are often called anti-patterns. We’ll learn when and how to use them, while keeping our code testable. Singleton Singleton is a class which has only one instance existing at…

Guide to mobile app autotesting tools

… for though it has many omissions and contains much that is apocryphal, or at least wildly inaccurate, it scores over the older, more pedestrian work in two important respects. First, it’s slightly cheaper; and secondly it has the words DON’T PANIC printed in large friendly letters on its cover. —…

Aspiring team lead?

Six tips on how to meet deadlines and develop your team When I became a team lead for the first time, I started going to lots of conferences and reading deep books on team management. I was reading all about what I should be and how I should develop, but it was still not clear to me what exactly I should…