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…

Modularising an iOS app

At Bumble — the parent company operating Badoo and Bumble apps — the iOS development team have been involved in creating modules for several years now. A large part of the new code is also being developed outside the apps’ code base. As a result of this work, we now…

MVI in Kotlin Multiplatform — part 1 (1 of 3)

About a year ago I became interested in some new technology: Kotlin Multiplatform. Since then I have been actively experimenting in this area and promoting this technology within our company. One outcome, for example, is our Reaktive library — Reactive extensions for Kotlin Multiplatform. The story continues here: MVI in Kotlin…

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…

Deep Neural Networks & Image Captioning

Part 2: Using attention networks to improve the quality of image captions In my previous blog, I introduced the concept of combining a CNN with an LSTM to generate a caption of an image, and talked about how we are using this at Badoo to help our users find love. This time, we will explore how the incorporation of attention networks can…

A Custom LayoutManager Case: Bumble Beeline

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High-Precision Time: how to use fractional seconds in MySQL and PHP

Once I caught myself thinking about time in databases and realised that I nearly always used time with one-second precision just because it was a common way to it, as well as because that was exactly what was written in manuals in lots of examples. Today, however, this level of…

Fixing serialization of Kotlin objects once and for all

Some time ago, I read an article describing a problem experienced with Kotlin objects and serialization using built-in Java methods. The author suggests an amazing solution involving adding the readResolve method to each object implementing java.io.Serializable rather than using instance checks. Despite this approach seemingly being the most correct one…

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…

From zero to Cosmos — Part #1

This is the story of how a small style guide that was first introduced under the radar, became so appreciated by both developers and designers that it eventually became a complex unification project — a design system called Cosmos. As some of you may know, every good story follows a…

Informal relationships

Many years ago I joined a company as a developer and soon witnessed something odd. Another department’s teamlead called up one of his subordinates in the middle of the day and told him: ‘Here, come and get this money and go to a store and grab me some drinks and…

How we achieved a 6x reduction of ANRs. Part 1: Collecting Data

One of the worst things that can happen to your app’s responsiveness is an Application Not Responding (ANR) dialogue. A high ANR rate may affect user experience and, potentially, Google Play search positions and featuring. At the beginning of the year, we had ANR rate above the Google Play threshold…

Cron in Linux: history, use and structure

There is an age-old classical saying that happy people don’t watch the clock. There weren’t any programmers or Unix operating systems in those pre-civilisation times, but in our day programmers know for sure that cron is watching the clock for them. For me, command-line utilities are both a passion and…

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…

#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…

Scalable Jetpack Compose Navigation

Introduction For one of my recent personal projects, I decided to make Jetpack Compose a first-class citizen. For me, this meant that my app would use a single activity, and all the navigation would be performed using Compose. When I originally started investigating the feasibility of this, Jetpack Compose Navigation did…

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. —…

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…

Top 5 Bumble Android AMA

A few weeks ago, our Bumble — the parent company operating Badoo and Bumble apps — Android team hosted their first Ask Me Anything (AMA) session on Reddit. It was great! Our Android apps are huge: they have over 1.3 million lines of code, over 210 million downloads on the…

System under control — how to automate integration tests

Nobody wants to discover a production service laying down and not working, or even failing to behave as expected, with errors and incorrect data processing. On one occasion, we — Bumble, the parent company operating Badoo and Bumble apps — decided to greatly reduce such inappropriate behaviour through the use…

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…

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?

How many people does it take to change a light bulb?

aka API-Centric Development in Non-API Company (Based on a talk by Konstantin Yakushev @ Nordics APIs) The answer is 24, one to hold the light bulb and … Okay, it’s a bad joke, but the number is right and I’ll explain it why later. Today’s topic is how we ended up developing an API-Centric Development environment…

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…

Checking your app’s paid services without losing money

Checking paid services is crucial in Badoo and Bumble apps testing process. Our applications are integrated with 70 payment providers in 250 countries. This means that bugs at any integration can seriously affect revenues, and in unpredictable ways. In this article, you will learn about methods that we employ in…